fix: resolve infinite loop in _find_config on Windows systems

[Julfried]

Issue #4967

Description of changes:
This PR fixes an infinite loop in _find_config that occurs on Windows systems. The issue was caused by using Path.match("/") to detect root directories, which never matches on Windows due to different path separators.

Changes made:

1. Replace platform-specific Path.match("/") with Path.anchor comparison
2. Implement proper root directory detection for both Windows and Unix systems
3. Add comprehensive cross-platform tests

Testing done:

• Verified fix on both Windows and Linux systems
• Added test_find_config_cross_platform to validate:
  • Basic path traversal
  • Nested directory structures
  • Root directory handling
  • Non-existent config scenarios
• Added test_find_config_path_separators to verify handling of:
  • Forward slashes
  • Backslashes
  • Mixed separators
• All existing tests pass without modification

Merge Checklist

General

• I have read the CONTRIBUTING doc
• I certify that the changes I am introducing will be backward compatible
• I used the commit message format described in CONTRIBUTING
• I have passed the region in to all S3 and STS clients (N/A for this change)
• I have updated necessary documentation (N/A - internal implementation change)

Tests

• I have added tests that prove my fix is effective
• I have added unit tests to ensure backward compatibility
• I have checked that my tests are not configured for a specific region or account
• I have used unique_name_from_base for resource names (N/A - unit tests only)
• No new dependencies added

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Julfried]

Quick update: I was unsure about two checklist items and checked them with N/A, because I think they are not applicable for my changes:

1. "Passed region to S3/STS clients"
2. "Documentation updated"

Please let me know if there is anything I need to do, to get this merged. Thanks!

[ahmednmourad]

I have been struggling with this for days. Thank you!

[Julfried]

Thanks, hopefully they merge this soon, because this bug is really confusing and frustrating. Especially for new users!

[Julfried]

Hey @nargokul

Just following up on this PR! The fix resolves a frustrating infinite loop issue on Windows (#4967) caused by a root path detection method that only worked on Linux. It updates the logic to properly handle cross plattform paths.

Looks like the CI is stuck on the wait-for-approval step—would you mind approving it so the checks can run? Let me know if there’s anything else I should adjust.

Thanks!

[Julfried]

Since this PR seems to be stale, I’d like to follow up to see if there’s anything else needed from my side to move it forward.

@benieric, @pintaoz-aws – Would you be able to take a look at this? I’ve recently rebased the branch to the latest master to ensure it’s up-to-date and ready for review.

This fix addresses a frustrating bug (#4967) that causes an infinite loop on Windows systems. Resolving this would greatly improve the developer experience, especially for new users facing this issue.

Please let me know if any further changes or additional information are needed. Thanks for your time and support!

[benieric]

Hey sorry for the delay! Thanks for raising this fix and adding tests will look to get this merged ASAP

[benieric]

Aiming to get this included in next release if tests are passing, thanks!

[benieric]

Can you run tox -e black-format to fix codestyle errors. We'll get this in the next release once tests passing

[Julfried]

Hey @benieric,

No worries about the delay—I really appreciate your help! I’ve fixed the formatting style as requested.
Just glad to get this merged—let me know if anything else is needed! 🙂