When passing a pathlib.Path object to send_photo(), send_document(), or other file-sending methods, the library was generating a ResourceWarning due to an unclosed file handle. This became a critical issue in CI/CD environments using pytest with the -W error flag, causing tests to fail.

Problem

The issue occurred in the parse_file_input function where:

return InputFile(path.open(mode="rb"), filename=filename, attach=attach)

The file handle created by path.open() was passed to InputFile, which read the content but never explicitly closed the original handle. When the handle was garbage collected, Python issued a ResourceWarning.

Solution

Modified the code to use a context manager that ensures proper file closure:

with path.open(mode="rb") as file_handle:
    return InputFile(file_handle, filename=filename, attach=attach)

This minimal change ensures the file handle is automatically closed after InputFile reads the content, preventing the ResourceWarning.

Testing

• Added a new test test_parse_file_input_path_no_resource_warning that specifically checks for the absence of ResourceWarning when using pathlib.Path
• All existing tests continue to pass, confirming no regressions
• Verified the fix resolves the original issue scenario

The change is surgical and maintains full backward compatibility while properly managing file resources.

Fixes #4907.

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