Validate component properties #264 - March 1

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.

[rmarren1]

Note: This PR is a continuation of #340. That PR had ~80 comments (most were outdated and no longer relevant), and 96 commits. This PR is the same code, just more readable.

---

PR for #264

Current Prerelease

pip install dash==0.35.0rc1
pip install dash-renderer==0.15.0rc1
pip install dash-core-components==0.42.0rc1
pip install dash-html-components==0.14.0rc6

Validation is on by default. To turn it off, you can set app.config.suppress_validation_exceptions = True

Test Cases to run for demo

import dash
import dash_html_components as html
import dash_core_components as dcc
import plotly.graph_objs as go
from dash.dependencies import Input, Output
app = dash.Dash()
app.scripts.config.serve_locally=True
app.layout = html.Div([
html.Button(id='click1', children='click to return bad Div children'),
html.Div(id='output1', **{'data-cb': 'foo'}),
html.Button(id='click2', children='click to return a bad figure'),
dcc.Graph(id='output2', figure={'data': [], 'layout': {}}),
html.Button(id='click3', children='click to return a bad radio'),
dcc.RadioItems(id='output3', options=[{'value': 'okay', 'label': 'okay'}]),
html.Button(id='click4', children='click to make a figure with no id'),
html.Div(id='output4'),
])
@app.callback(Output('output1', 'children'),
[Input('click1', 'n_clicks')])
def crash_it1(clicks):
if clicks:
return [[]]
return clicks
@app.callback(Output('output2', 'figure'),
[Input('click2', 'n_clicks')])
def crash_it2(clicks):
if clicks:
return {'data': {'x': [1, 2, 3], 'y': [1, 2, 3], 'type': 'scatter'}, 'layout': {}}
return go.Figure(data=[go.Scatter(x=[1,2,3], y=[1,2,3])], layout=go.Layout()) @app.callback(Output('output3', 'options'),
[Input('click3', 'n_clicks')])
def crash_it3(clicks):
if clicks:
return [{'value': {'not okay': True}, 'labl': 'not okay'}]
return [{'value': 'okay', 'label': 'okay'}]
@app.callback(Output('output4', 'children'),
[Input('click4', 'n_clicks')])
def crash_it4(clicks):
if clicks:
return dcc.Graph()
return dcc.Graph(id='hi')
app.run_server(debug=True, port=8050)

Example Error Messages

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(1)` as arguments.
This function call returned `{'layout': {}, 'data': {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}}`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'validator': 'plotly_figure'}
***************************************************************
The errors in validation are as follows:
* figure	<- Invalid Plotly Figure:
Invalid value of type '__builtin__.dict' received for the 'data' property of Received value: {'y': [1, 2, 3], 'x': [1, 2, 3], 'type': 'scatter'}
The 'data' property is a tuple of trace instances
that may be specified as:
- A list or tuple of trace instances
(e.g. [Scatter(...), Bar(...)])
- A list or tuple of dicts of string/value properties where:
- The 'type' property specifies the trace type
One of: ['mesh3d', 'splom', 'scattercarpet',
'scattergl', 'scatterternary', 'pie',
'surface', 'histogram', 'ohlc', 'heatmapgl',
'cone', 'scatterpolar', 'table',
'scatterpolargl', 'histogram2d', 'contour',
'carpet', 'box', 'violin', 'bar',
'contourcarpet', 'area', 'choropleth',
'candlestick', 'streamtube', 'parcoords',
'heatmap', 'barpolar', 'scattermapbox',
'scatter3d', 'pointcloud',
'histogram2dcontour', 'scatter', 'scattergeo',
'sankey']
- All remaining properties are passed to the constructor of
the specified trace type
(e.g. [{'type': 'scatter', ...}, {'type': 'bar, ...}])

CallbackOutputValidationError: A Dash Callback produced an invalid value!
Dash tried to update the `options` prop of the
`RadioItems` with id `output3` by calling the
`crash_it3` function with `(1)` as arguments.
This function call returned `[{'value': {'not okay': True}, 'labl': 'not okay'}]`, which did not pass
validation tests for the `RadioItems` component.
The expected schema for the `options` prop of the
`RadioItems` component is:
***************************************************************
{'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type
* labl	<- unknown field

ComponentInitializationValidationError: A Dash Component was initialized with invalid properties!
Dash tried to create a `RadioItems` component with the
following arguments, which caused a validation failure:
***************************************************************
{'id': 'output3', 'options': [{'label': 'okay', 'value': {}}]}
***************************************************************
The expected schema for the `RadioItems` component is:
***************************************************************
{'className': {'type': 'string'},
'dashEvents': {'allowed': ['change'], 'type': ('string', 'number')},
'fireEvent': {},
'id': {'type': 'string'},
'inputClassName': {'type': 'string'},
'inputStyle': {'type': 'dict'},
'labelClassName': {'type': 'string'},
'labelStyle': {'type': 'dict'},
'options': {'schema': {'allow_unknown': False,
'nullable': False,
'schema': {'disabled': {'type': 'boolean'},
'label': {'type': 'string'},
'value': {'type': 'string'}},
'type': 'dict'},
'type': 'list'},
'setProps': {},
'style': {'type': 'dict'},
'value': {'type': 'string'}}
***************************************************************
The errors in validation are as follows:
* options
* 0
* value	<- must be of string type

PropTypes to Cerberus reference

PropType	Cerberus Schema Validated Against	Known Current Limitations
array	{'type': 'list'}
bool	{'type': 'boolean'}
func	{}	No validation occurs.
object	{'type': 'dict'}	Validates that input is explicitly a dict object. We cannot be more general (e.g. collections.abc.Mapping) since the core Component is an instance of that.
string	{'type': 'string'}
symbol	{}	No validation occurs
node	{'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}, {'type': 'list', 'schema': {'anyof': [{'type': 'component'}, {'type': 'boolean'}, {'type': 'number'}, {'type': 'string'}]}}]}
instanceOf(Object)	{}	No validation occurs
oneOf(['val1', 2])	{'allowed': [None, 'val1', 2]}	Strings will have ' characters stripped off each end. This is because metadata.json generation serializes the literal values as json, so for example PropTypes.oneOf(['News', 'Photos']) serializes to ["'News'", "'Photos'"]. reactjs/react-docgen#57
oneOfType( [ PropTypes.string, PropTypes.bool ] )	{'anyof': [{'type': 'string', 'type': 'boolean'}]}	If one of the types is a PropType that cannot be validated individually (e.g. PropType.func), no validation will occur and the schema will effectively be {}
arrayOf( PropTypes.number )	{'type': 'list', 'schema': {'type': 'number'}}
objectOf( PropTypes.number )	{'type': 'dict', 'valueschema': {'type': 'number'}}
shape( { k1: PropTypes.string, k2: PropTypes.number } )	{'type': 'dict', 'allow_unknown': False, 'schema': {'k1': {'type': 'string}, 'k2': {'type': 'number'}}}
any	{'type': ('boolean', 'number', 'string', 'dict', 'list')}

[rmarren1]

@T4rk1n I made the commit history more readable, hopefully this is easier to review. This includes fixes to address the review you made in #340

[T4rk1n]

Thanks, I'll have a good look on friday review party.

[T4rk1n]

Why do that in two difference part ? Couldn't your additions in dispatch be in add_context ?

[rmarren1]

We would have to pass namespace, component_id, component_property, to this since that info is available in dispatch. I originally thought this might clash with the other arguments (e.g. if you had a property called namespace) although I now think this would be fine, but it might make it difficult if we want to support passing props with keyword arguments in the future.

[rmarren1]

• - Fix app.layout = html.Div({'hello'}) -> TypeError: set(['hello']) is not JSON serializable
  Had to change the list validation logic to exclude set, it was being included since it is castable to a list but erroring since it is not serializable as a list
• - AttributeError: MyOtherType instance has no attribute '__trunc__'
  Had to adjust number validation logic, normally things throw a ValueError if they are not castable to an int, but this was an exception

For the dash-html-components I am currently only validating children since all dash-html-components proptypes are strings, as discussed in plotly/dash-html-components#71. I think this should be re-visited. I do not think we should manually type each component since there are too many props, but I think it would be reasonable for now to ensure that all non-children props are scalars (e.g. str, int, bool, or None).

[rmarren1]

Updates:

• Discovered and fixed an issue where required falsy values were not detected (e.g. on dcc.Checklist, if values=[] it would not properly detect it and say values is required during validation).
• Removed old method of required component validation (e.g. a check in the __init__ function of a component). This is now handled by validation done in this PR.
• [ X] Discovered a small issue in figure validation. The plan was to run a figure value for go.Figure for validation, but there is one issue in dash-docs where go.Figure will error when a proper plot would have been produced. (Pass figure through go.Figure for validation? dash-core-components#257 (comment)) Edit: looks like this was actually a bug in plotly.py, so we should be fine.

Bumped all release candidates.

[rmarren1]

Tested the RCs with dash-docs, and a few Dash apps I have built.
@plotly/dash if you have a large dash app and some time, please try to run it with these RCs and let me know how it goes!

[rmarren1]

• rebased dash, dash-html-components and dash-core-components
• bumped versions in top level comment
• sanity check on dash-docs: https://github.com/plotly/dash-docs/pull/314
  @T4rk1n please take another look, hopefully we are getting close!

[T4rk1n]

Testing the demo with the rc version I got a figure validation error and the message:

You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Validation is on by default. To turn it off, you can set app.config.disable_component_validation = True

Is it app.config.disable_component_validation or app.config.suppress_validation_exceptions ?

[T4rk1n]

Dash tried to update the `figure` prop of the
`Graph` with id `output2` by calling the
`crash_it2` function with `(None)` as arguments.
This function call returned `Figure({
'data': [{'type': 'scatter', 'uid': '91f6c03c-17bb-42a3-a502-4d9441696413', 'x': [1, 2, 3], 'y': [1, 2, 3]}],
'layout': {}
})`, which did not pass
validation tests for the `Graph` component.
The expected schema for the `figure` prop of the
`Graph` component is:
***************************************************************
{'nullable': False, 'required': False, 'type': 'dict'}
***************************************************************
The errors in validation are as follows:
* figure	<- must be of dict type
You can turn off these validation exceptions by setting
`app.config.suppress_validation_exceptions=True`

Shouldn't Figure be valid ?

[T4rk1n]

html.Button(id='click4', children='click to make a figure with no id'),

I think the graph now put a random id if there's none.

[chubukov]

Wanted to note that the issue I raised in the other thread still exists. Numerical types in checklist values and dropdown values (and probably other components too) still raise errors with the latest release.

[rmarren1]

Updated top level comment, the correct way to turn off validation is by setting app.config.suppress_validation_exceptions, not app.config.disable_component_validation. This was changed to have a parallel config to the current app.config.suppress_callback_exceptions

[chriddyp]

This was a really great effort and was in line to be a PR of the Year 🏆 . In the end, with the addition of alternative language backends for Dash (DashR), we decided to double down on the Dash Dev Tools UI and invest & maintain the validation code in the front-end.