Enable mypy attr defined

[m-vdb]

Proposed changes:

• Fix Enable mypy attr-defined error code #9098

Status (please check what you already did):

• added some tests for the functionality
• updated the documentation
• updated the changelog (please check changelog for instructions)
• reformat files using black (please check Readme for instructions)

[m-vdb]

@joejuzl I'm almost done on this PR and I need your help to figure the last type issue:

• mypy doesn't like this code, here is the CI issue
• here we define self._policy_schema_nodes as a List[SchemaNode] but really it is a "list of SchemaNode that represent a Policy"
• I don't want to modify the code more than necessary here. One way to go about it would be to have a PolicySchemaNode that inherits SchemaNode but modifies uses to be Policy instead.

Do you have another idea?

[joejuzl]

Can you cast policy_node.uses to Policy? Or maybe even adding a isinstance or issubtype check in the generator comprehension would make mypy happy?
Also if there's no easy workaround, we always consider disabling a rule for one line, it's explicit at least.

[m-vdb]

will give a try to those 👍🏻

[m-vdb]

I went with the cast(Policy, ...), it's simple and explicit and I think it's better than to just disable the check

[ancalita]

🚀

[ancalita]

To double-check I understand this correctly, if there's 3rd party code without type hints without type hints, mypy will complain?

[m-vdb]

yes exactly. It's enabled by

rasa/setup.cfg

Line 43 in 348697b

disallow_untyped_calls = True

[ancalita]

@m-vdb I've just merged main to my mypy branch and getting some unrelated errors to the check I enabled (union-attr), full list here - is the fix to run make install to get latest mypy version?

rasa/utils/tensorflow/model_data.py:420: error: unused "type: ignore" comment
rasa/shared/core/trackers.py:86: error: Variable "typing_extensions.TypeAlias" is not valid as a type  [valid-type]
rasa/shared/core/trackers.py:86: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
rasa/shared/core/trackers.py:725: error: Variable "rasa.shared.core.trackers.EventTypeAlias" is not valid as a type  [valid-type]
rasa/shared/core/trackers.py:725: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
rasa/shared/core/trackers.py:729: error: Variable "rasa.shared.core.trackers.EventTypeAlias" is not valid as a type  [valid-type]
rasa/shared/core/trackers.py:729: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
rasa/core/lock_store.py:229: error: Library stubs not installed for "redis" (or incompatible with Python 3.8)  [import]
rasa/core/lock_store.py:229: note: Hint: "python3 -m pip install types-redis"
rasa/core/lock_store.py:229: note: (or run "mypy --install-types" to install all missing stub packages)
rasa/core/lock_store.py:229: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
rasa/shared/importers/importer.py:175: error: Too many arguments  [call-arg]
rasa/core/tracker_store.py:319: error: Library stubs not installed for "redis" (or incompatible with Python 3.8)  [import]
rasa/core/actions/action.py:863: error: EventTypeAlias? has no attribute "parse_data"  [attr-defined]
rasa/server.py:1368: error: unused "type: ignore" comment

[ancalita]

@m-vdb edit: running make install cleared these errors - all good now. Just have more union-attr errors to fix than before actually 😅

[m-vdb]

👍🏻 yeah, sorry I didn't mention that you needed to run make install. I'll share a message in #atom-squad