Fix TypeError: 'NoneType' object is not iterable during deserialization

[Jiashuo Li (jiasli)]

msrest can't handle attribute map >= 3 layers during deserialization.

For example, for LongTermEnvironmentCreateOrUpdateParameters

'data_retention': {'key': 'properties.warmStoreConfiguration.dataRetention', 'type': 'duration'},

properties.warmStoreConfiguration.dataRetention has 3 layers. The regex matching this pattern is

'properties\..+?\..+?'

The CLI code I use to construct the body is

body= {}
body['kind'] ='LongTerm'body['location'] =location# strbody['tags'] =tags# dictionarybody.setdefault('sku', {})['name'] =sku_name# strbody.setdefault('sku', {})['capacity'] =sku_capacity# numberbody['time_series_id_properties'] = [{"name": "deviceId", "type": "String"}, {"name": "deviceId2", "type": "String"}] # [TimeSeriesIdProperty]body['storage_configuration'] = {"account_name": storage_account_name, "management_key": storage_management_key} # LongTermStorageConfigurationInputbody['data_retention'] =data_retentionreturnclient.create_or_update(resource_group_name=resource_group, environment_name=name, parameters=body)

Got error:

cli.azure.cli.core.util : Unable to build a model: Unable to deserialize to object: type, TypeError: 'NoneType' object is not iterable, DeserializationError: Unable to deserialize to object: type, TypeError: 'NoneType' object is not iterable
Traceback (most recent call last):
File "d:\cli\msrest-for-python\msrest\serialization.py", line 1328, in _deserialize
found_value = key_extractor(attr, attr_desc, data)
File "d:\cli\msrest-for-python\msrest\serialization.py", line 1110, in rest_key_case_insensitive_extractor
working_data = attribute_key_case_insensitive_extractor(working_key, None, working_data)
File "d:\cli\msrest-for-python\msrest\serialization.py", line 1132, in attribute_key_case_insensitive_extractor
for key in data:
TypeError: 'NoneType' object is not iterable

This is because it first tries to extract properties from the body and gets None, but it doesn’t stop there because warmStoreConfiguration.dataRetention still has . and it continues to extract warmStoreConfiguration from None which results in an error.

This PR makes the loop continue only if working_data evaluates to True.

[Laurent Mazuel (lmazuel)]

Jiashuo Li (@jiasli) I'm still not sure, but right now my inclination is more to add a new extractor:

defrest_key_extractor_fail_safe(*args, **kwargs):
try:
returnrest_key_extractor(*args, **kwargs):
exceptException:
returnNone

and then plug this one in the case of the serializer. Making the whole extractor robust, will impact error on regular deserialization from server (this is used in both context).

[Laurent Mazuel (lmazuel)]

That's not enough, when it's None you will end the loop and still fail line 1098

[Jiashuo Li (jiasli)]

Nice catch. I only looked at the code at L1113~L1114, but didn't notice L1098. I thought they were the same. :P

[Laurent Mazuel (lmazuel)]

Jiashuo Li (@jiasli) see my comment, I can't merge it as is, and Rodge Fu (@RodgeFu) also found #197 as related issue, so I'm fixing it in #198
That being said, to be sure you're credited in solving this issue I cherry-picked your commit (even if I didn't fix it like you proposed exactly)

[Jiashuo Li (jiasli)]

Thanks for looking at this issue Laurent Mazuel (@lmazuel). I am fine with it as long as the issue is properly addressed. Meanwhile, I switched my code to use the Model directly, therefore bypassing this issue.