Fix mypy type errors across service-related files in Selenium WebDriver

[Bradltr95]

User description

🔗 Related Issues

#15697

💥 What does this PR do?

This PR resolves type annotation issues flagged by mypy in various service.py files within the Selenium WebDriver codebase. It ensures compatibility between assigned values and their expected types.

🔧 Implementation Notes

The changes involve explicit type casting and validation to align with the expected types defined in the base classes. This approach was chosen to maintain backward compatibility while resolving type errors.

🔄 Types of changes

• Bug fix (backwards compatible)

---

PR Type

Bug fix

---

Description

• Fixes mypy type annotation errors across multiple files

• Adds explicit type casting and validation for constructor arguments

• Ensures correct types in data class factory methods and dictionary conversions

• Improves runtime type safety and error handling in service and connection classes

---

Changes walkthrough 📝

Relevant files

Bug fix

15 files service.py Fix type annotation for log_output assignment                        +1/-1      webdriver.py Enforce type safety for options, service, and executor      +10/-4    browser.py Add explicit type conversions in from_dict                              +7/-7      browsing_context.py Add type conversions and Callable typing for event handlers +34/-34  cdp.py Add runtime check for devtools.target in connect_session  +4/-0      storage.py Add type conversions in Cookie and CookieFilter methods    +10/-10  options.py Add explicit type for mobile_options and binary_location  +2/-1      service.py Refactor log_output handling for type safety                          +5/-5      utils.py Add type conversions for socket and key processing              +4/-4      virtual_authenticator.py Remove redundant type annotations in Enum subclasses          +6/-6      remote_connection.py Add explicit type for browser_name                                              +1/-1      remote_connection.py Add explicit type for extra_commands                                          +2/-1      webdriver.py Add type checks, casting, and error handling for attributes and methods +29/-15  service.py Make DEFAULT_EXECUTABLE_PATH Optional for type safety        +1/-1      service.py Make executable_path Optional in Service constructor          +1/-1

---

Need help?

Type /help how to ... in the comments thread for any questions about Qodo Merge usage.

Check out the documentation for more information.

[qodo-merge-pro]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis 🔶 15697 - Partially compliant Compliant requirements: Fix type annotation errors flagged by mypy in the Python bindings Go through the codebase and fix all errors that Mypy finds Non-compliant requirements: Update CI job to fail when Mypy encounters errors to enforce no future regressions

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Potential Bug The execute method now checks if command_executor is an instance of RemoteConnection before calling its execute method, but the response variable is used before being defined if this check fails. if response: self.error_handler.check_response(response) response["value"] = self._unwrap_value(response.get("value", None)) Redundant Code The session_id variable is assigned twice - once conditionally and once unconditionally, which could lead to unexpected behavior. if devtools and devtools.target: session_id = await self.execute(devtools.target.attach_to_target(target_id, True)) else: raise RuntimeError("devtools.target is not available.") session_id = await self.execute(devtools.target.attach_to_target(target_id, True)) Potential Error The service validation check is added after the service is already used in the DriverFinder constructor, which could lead to NoneType errors. if self.service is None: raise ValueError("Service must be provided and cannot be None") finder = DriverFinder(self.service, options)

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Remove duplicate function call There's a duplicate call to self.execute(devtools.target.attach_to_target(target_id, True)) after the if-else block. This will cause the function to execute twice, potentially creating multiple sessions. py/selenium/webdriver/common/bidi/cdp.py [430-434] if devtools and devtools.target: session_id = await self.execute(devtools.target.attach_to_target(target_id, True)) else: raise RuntimeError("devtools.target is not available.") -session_id = await self.execute(devtools.target.attach_to_target(target_id, True)) Apply / Chat Suggestion importance[1-10]: 9 __ Why: This correctly identifies a serious bug where session_id is assigned twice, causing the function to execute unnecessarily and potentially creating multiple sessions.	High
	Fix incorrect type casting The current code attempts to cast None to IOBase which is incorrect. Instead, use Optional[IOBase] to properly type-hint that log_output can be None or an IOBase object. py/selenium/webdriver/chromium/service.py [50-52] if isinstance(log_output, str): self.service_args.append(f"--log-path={log_output}") - self.log_output: cast(IOBase, None) + self.log_output: Optional[IOBase] = None Apply / Chat Suggestion importance[1-10]: 7 __ Why: The suggestion correctly identifies that cast(IOBase, None) is semantically incorrect since None is not an IOBase object. Using Optional[IOBase] = None is more accurate typing.	Medium
More

[cgoldberg]

I think type hinting can be useful, but I don't like the idea of forcing type conversions and type checking everywhere just to keep Mypy happy. Python is very much a dynamically typed language that makes heavy use of duck-typing, and most of these changes don't feel "pythonic".

I'd be curious to hear what other people think and ideas for how we should better handle type hinting across the codebase.

[Bradltr95]

I think type hinting can be useful, but I don't like the idea of forcing type conversions and type checking everywhere just to keep Mypy happy. Python is very much a dynamically typed language that makes heavy use of duck-typing, and most of these changes don't feel "pythonic".

I'd be curious to hear what other people think and ideas for how we should better handle type hinting across the codebase.

Thanks for the input.. So, just to understand, its okay to have type hinting such as: cf9fda4#diff-2f176dbccc5f64167acc6345e2351cab42ccebdefcc77374c69cb9e23b130806R24
and cf9fda4#diff-5ff2f2a84a79fce9e04511b572dcaab921c08e956345f4c41b7e701d4d018589R425.

However, we don't want to cast every type just to resolve errors like: cf9fda4#diff-b1516e150256fb4a5ef5144d5d8314fc45e92872415ba8900d4cd8d2cc9b9841R70

Or do you think both the type hinting and casting pull away from the dynamic typing of python?

In this case I figured at the very least the type hinting would help with better code readability as it explicitly states the types on top of resolving the mypy errors. However, I agree it gets away from the dynamically typed nature of python.

If you feel both solutions (casting AND type hinting) aren't useful, we can go ahead and close this PR :)