[py] Addressing mypy type annotation errors

[bandophahita]

User description

🔗 Related Issues

addresses part of #15697

💥 What does this PR do?

Updates annotations and sets proper default objects.

🔧 Implementation Notes

💡 Additional Considerations

🔄 Types of changes

• Cleanup (formatting, renaming)
• Bug fix (backwards compatible)

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PR Type

Other

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Description

• Fix mypy type annotation errors across webdriver services

• Change Sequence[str] to list[str] for service arguments

• Add explicit type annotations for class attributes

• Update ChromiumDriver constructor parameter types

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Changes walkthrough 📝

	Relevant files
Bug fix	3 files service.py Update service_args type annotations to list[str]                +4/-4      service.py Fix type annotations and add attribute declarations            +6/-4      service.py Change service_args type from Sequence to list                      +3/-3
Enhancement	4 files webdriver.py Add explicit type annotations for options and service        +3/-0      webdriver.py Update constructor parameter types and imports                      +6/-7      service.py Add log_output type annotation declaration                              +2/-0      webdriver.py Add explicit type annotations for attributes                          +3/-0

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PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis ✅ 15697 - PR Code Verified Compliant requirements: Fix mypy type annotation errors across webdriver services Change Sequence[str] to list[str] for service arguments Add explicit type annotations for class attributes Update ChromiumDriver constructor parameter types Requires further human verification: Verify that all mypy errors are resolved after these changes Confirm backward compatibility is maintained

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Complex Type The log_output attribute has an overly complex Union type annotation that could be simplified and may indicate unclear type requirements. log_output: Union[Optional[IOBase], Optional[Union[int, IOBase]], Optional[SubprocessStdAlias]] Breaking Change Constructor parameters changed from Optional to required, which could break existing code that relies on None defaults. browser_name: str, vendor_prefix: str, options: ChromiumOptions = ChromiumOptions(), service: ChromiumService = ChromiumService(),

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
General	✅ Simplify complex type annotation Suggestion Impact: The suggestion impacted the commit by simplifying the complex type annotation, though the implementation differs slightly from the suggested approach code diff: - log_output: Union[Optional[IOBase], Optional[Union[int, IOBase]], Optional[SubprocessStdAlias]] + log_output: Union[None, IOBase, int, SubprocessStdAlias] The type annotation is overly complex with nested Optional types. Simplify to Optional[Union[int, IOBase, SubprocessStdAlias]] for better readability and correctness. py/selenium/webdriver/chromium/service.py [38] -log_output: Union[Optional[IOBase], Optional[Union[int, IOBase]], Optional[SubprocessStdAlias]] +log_output: Optional[Union[int, IOBase, SubprocessStdAlias]] [Suggestion processed] Suggestion importance[1-10]: 5 __ Why: The suggestion correctly identifies that the nested Optional and Union types in the type hint for log_output can be simplified. Applying the suggestion improves code readability and adheres to type hinting best practices.	Low
Update

[navin772]

@bandophahita Thank you for the contribution! This looks good.
Could you also add mypy fixes for wpewebkit/service.py and webkitgtk/service.py in this PR, those are quite similar to the ones you updated above and will fix type errors for all service.py files.

Also, run the formatter - ./scripts/format.sh to get the CI passing.

[cgoldberg]

Change Sequence[str] to list[str] for service arguments

Why do we need this? What's wrong with accepting a sequence?

[bandophahita]

Change Sequence[str] to list[str] for service arguments

Why do we need this? What's wrong with accepting a sequence?

Need is probably too strong of a term. It made sense to me to keep it a list since that's what _service_args is and that's how all of the code internally passes arguments. Nothing would prevent accepting a Sequence since it is converted to a list in the __init__.

Short answer; keeping the types simple prevents confusion. But in case that's an issue, I reverted the argument annotations.

[cgoldberg]

I reverted the argument annotations.

I still see a change from Sequence to list. Just leave them as a sequence unless there is a need to enforce a list.

[bandophahita]

I still see a change from Sequence to list. Just leave them as a sequence unless there is a need to enforce a list.

There are changes from Sequence to list but those are attributes. I reverted the argument annotations.

[bandophahita]

I still see a change from Sequence to list. Just leave them as a sequence unless there is a need to enforce a list.

I think I should explain the change. The problem was when referencing service.service_args (which is a property returning _service_args) it was annotated as a Sequence; and yet internally there were actions that can only be performed as a list object. Mypy was catching and reporting this inconsistancy. Sequence is fine for the argument being passed in, but it was then being converted to a list. The annotation was in incorrect for the attribute.

[cgoldberg]

@bandophahita can you explain why we need the new class attributes?

[bandophahita]

@bandophahita can you explain why we need the new class attributes?

For sure. These are technically not NEW attributes but simply annotations for the class attributes. They dont do anything at runtime. Mypy reads them as the annotations instead of autodetecting/using what is set in the __init__. Mypy sometimes can't deterimne what a dynamic attribute is very well, these help it. I can go through them and breakdown how, if you want.

[bandophahita]

This class annotation lets mypy understand that the webdriver has an attribute service that is an instance of Service. The Optional[Service] argument annotation caused mypy to believe the attribute webdriver.servce could be None, when in fact it never is. Mypy isn't smart enough to read the code that way.

[bandophahita]

Annotation to let mypy know what log_output attribute can be. Autodetermination wasn't smart enough to see past the argument annotation which was fine for the argument but incomplete for the attribute.

[bandophahita]

There is a real possibility that the argument annotation is incomplete here too. I didn't address this. Someone more familiar with the log_output argument should confirm it's annotation.