Idle: improve stack viewer

[terryjreedy]

BPO	24790
Nosy	@terryjreedy, @roseman, @JimJJewett
Files	issue24790.1.patch: Patch for the first item in the list

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/terryjreedy'
closed_at = None
created_at = <Date 2015-08-05.00:29:22.378>
labels = ['expert-IDLE', 'type-bug', '3.10']
title = 'Idle: improve stack viewer'
updated_at = <Date 2021-01-28.14:12:14.683>
user = 'https://github.com/terryjreedy'

bugs.python.org fields:

activity = <Date 2021-01-28.14:12:14.683>
actor = 'terry.reedy'
assignee = 'terry.reedy'
closed = False
closed_date = None
closer = None
components = ['IDLE']
creation = <Date 2015-08-05.00:29:22.378>
creator = 'terry.reedy'
dependencies = []
files = ['40213']
hgrepos = []
issue_num = 24790
keywords = ['patch']
message_count = 25.0
messages = ['248010', '248011', '248012', '248741', '248743', '248746', '248771', '248777', '248780', '248781', '248791', '248810', '248844', '248848', '248849', '248850', '248854', '248933', '248934', '249115', '249173', '249223', '249242', '267501', '385864']
nosy_count = 5.0
nosy_names = ['terry.reedy', 'markroseman', 'python-dev', 'Jim.Jewett', 'can.ibanoglu']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue24790'
versions = ['Python 3.10']

[terryjreedy]

Debug => Stack Viewer (no hot key) could become more useful, aside from bpo-23544, freezing Idle when Debugger active.

1. Don't include idlelib.run.runcode.
2. Don't duplicate globals under each function. Once for the module is enough.
3. Remove +Locals under each function and instead display locals when expanding Clicking a function should display locals without having to click anything else.
4. Add a button to expand all locals?

[terryjreedy]

5. Change title to something better than 'Idle'. Perhaps 'Idle Shell Traceback'?

[terryjreedy]

5b. Add Python version to end of , as with Shell window.

This will be more than one patch. Some should be easy.

[canibanoglu]

Hello,

I'm very interested in tackling this issue but this will be my first contribution to Python and I'm quite nervous. I have gone over the developer guide and FAQ but I would appreciate if you could let me know if I should approach this in a certain way.

[terryjreedy]

Welcome. I was hoping a new contributor would see the 'easy' tag. Nervous is okay as long as it leads to heighten carefulness without paralysis. I am still nervous hitting the [Commit] button.

1. Important. Sign the contributor agreement.
   https://www.python.org/psf/contrib/
   https://www.python.org/psf/contrib/contrib-form/
   I will not look at a patch until you say you have signed. I will not commit until the '*' appears on your name (perhaps a week).

2. Once you sign, I will give you at least a week to produce something before I work on this by myself. Patch needs to apply to 3.4, but StackViewer.py should be identical for 3.4/5/6.

3. Post a patch as soon as you do a complete chunk (any of the numbered items). Start with either 1. or 2. and switch if you get stuck.

Does above answer your question?

[canibanoglu]

It does indeed, thank you very much! I have signed the Contributor Agreement and will start working on this right away.

[canibanoglu]

Hello again,

I have spent some time going over the code and how the PyShell brings all of this together and have formed some loose opinions on how to solve these issues but I wanted to get a much more informed opinion.

I will provide a patch for the first one first, so right now, all my questions are related to that one.

Basically, I have come up with three different places I could patch in StackViewer.py to remove "idlelib.run.runcode" from the stack viewer.

First option is to patch the constructor of "StackTreeItem" so that if "idlelib.run.runcode" is in the traceback, it never gets pushed to the stack list. I don't like this approach very much because I would essentially be removing data from the stack.

Second option is to patch the "GetSubList" method so that the iterated variable "info" is checked before constructing a new "FrameTreeItem". If "idlelib.run.runcode" is matched, we would just continue to the next value in the list. I think this would lead to repetitive code though. We would rewrite some of the "GetText" method of "FrameTreeItem" and then make a string comparison to identify the entry to be removed.

Third option is to call the "GetText" method after each created "FrameTreeItem" and make the string comparison then. This would add a lot of method calls if the stack is long. On the other hand, this approach doesn't repeat any code.

It is highly possible that I have missed something very simple and elegant :) I would very much appreciate your input. I can make upload a patch once I get your approval. Which approach would be better here?

Something else that I would like to ask is the preparation of the patch file. Should switch to the 3.4 branch and then create the patch or can I do it at the dev branch? How would I check if the patch applies to 3.4/3.5/3.6 (apart from applying them manually and testing if it has the desired outcome)?

I'm sorry for the wall of text, I'm nervous and I don't want to mess something up. :)

Thanks a lot for your assistance.

[terryjreedy]

StackViewer.py seem to be identical in 3.4, 3.5, and 3.6, so a patch against any applies to all. The diff with 2.7 is

F:\Python\dev\36>hg diff -r 4884af6d3e30 f:/python/dev/36/Lib/idlelib/StackViewer.py
@@ -2,7 +2,7 @@
 import sys
 import linecache
 import re
-import Tkinter as tk
+import tkinter as tk

 from idlelib.TreeWidget import TreeNode, TreeItem, ScrolledCanvas
 from idlelib.ObjectBrowser import ObjectTreeItem, make_objecttreeitem
@@ -10,7 +10,7 @@

 def StackBrowser(root, flist=None, tb=None, top=None):
 if top is None:
- from Tkinter import Toplevel
+ from tkinter import Toplevel
 top = Toplevel(root)
 sc = ScrolledCanvas(top, bg="white", highlightthickness=0)
 sc.frame.pack(expand=1, fill="both")
@@ -109,7 +109,7 @@
 return len(self.object) > 0

 def keys(self):
- return self.object.keys()
+ return list(self.object.keys())

 def GetSubList(self):
 sublist = []

The second and third differences are due to unneeded code; I will remove them after I submit this message, so update your repository after I do that and then patch.

---
Your research is very helpful. The purpose of 1. *is* to remove data ;-) -- data that is only present because of Idle. The purpose of StackTreeItem.get_stack is to removed unneeded data while converting a linked list to a regular list. Note that the loop drops 2 of 4 fields. I do not know if
if tb and tb.tb_frame is None:
tb = tb.tb_next
actually removes anything, but after this, I believe that the idlelib.run.runcode node (or idlelib.PyShell.runcode node, when Idle is started with -n) is at the top of the linked list. So I believe adding
tb = tb.tb_next
after the above will do what we want. Try it, and if it works, move on.

---
6 (modeled after 3). Modules only have +Globals. Remove +Globals under each module and instead display globals when expanding. (There will only be a module other than __main__ when there is an error in another module being imported. We should then improve the lines to read
+ Globals for module __main__ ...
+ Locals for function xyz...

[python-dev]

New changeset 9ad330a9d785 by Terry Jan Reedy in branch '2.7':
Issue bpo-24790: Remove extraneous code (which also create 2 & 3 conflicts).
https://hg.python.org/cpython/rev/9ad330a9d785

New changeset 010264c9ceae by Terry Jan Reedy in branch '3.4':
Issue bpo-24790: Remove extraneous code (which also create 2 & 3 conflicts).
https://hg.python.org/cpython/rev/010264c9ceae

[terryjreedy]

7. Sorts global and local names (as with dir()).

8. Don't expand values with their class attributes, at least not for builtins. Example

+ <dir icon> __doc__ = None

Clicking + gives all the attributes of type(None), each with its own +. It does not do this for ints and strings.

[jimjjewett]

Terry: Was removing the public attribute keys OK?