Handle invalid submodule names during recursive updates

[Byron]

Tasks

This section is for Byron only. Models continuing this PR must not add, remove, check, uncheck, rename, or reorder checkboxes here.

• refackiew

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Everything below this line was generated by Codex GPT-5.

Created by Codex on behalf of Byron. Byron will review before this is ready to merge.

Reported issue

Initialize mrepo before swallowing validation failures

When an invalidly named submodule is updated directly with both recursive=True and keep_going=True, this validation error is swallowed, but execution then reaches the recursion block and reads mrepo before it has been assigned, raising UnboundLocalError instead of honoring keep_going. Fresh evidence in this revision is that the validation was moved inside the try without initializing mrepo on the non-dry-run path; initialize it before the try or skip recursion after the handled failure.

And in a separate stg commit: _module_abspath() only validates name when _need_gitfile_submodules() is true. This makes behavior depend on the installed git version and can allow invalid names to pass through this helper silently on older git versions (even though other code paths now expect invalid names to raise consistently). Consider validating name unconditionally at the start of the method and then using the validated value in the gitfile-submodules branch.

Changes

• Initialize the module repository sentinel before validation so handled failures safely skip recursion.
• Validate submodule names before selecting the Git-version-dependent module path branch.
• Cover direct recursive keep_going updates and the legacy module-path branch.

Git baseline

Git submodule.c at 883a47ef6496c96a5d6132ed8c87fcd44ebf8d1a validates submodule paths before filesystem operations.

Validation

• test/test_submodule.py: 40 passed, 1 skipped, 1 xfailed.
• git diff --check.
• One Codex review per commit hash; no substantive findings.

[Copilot]

Pull request overview

Fixes a crash path in recursive submodule updates when invalid submodule names are encountered with keep_going=True, and makes submodule-name validation consistent across Git-version-dependent code paths.

Changes:

• Validate submodule names unconditionally in Submodule._module_abspath() so invalid names fail consistently regardless of _need_gitfile_submodules().
• Initialize mrepo before the try in Submodule.update() so keep_going-handled validation failures don’t lead to UnboundLocalError during recursion.
• Extend tests to cover direct recursive=True, keep_going=True updates on invalid submodules and the legacy module-path branch.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
test/test_submodule.py	Adds regression coverage for invalid-name handling across both module-path branches and direct recursive updates with keep_going=True.
git/objects/submodule/base.py	Ensures name validation is applied consistently and prevents mrepo from being used before assignment when errors are swallowed.
.basedpyright/baseline.json	Removes a now-fixed “possibly unbound variable” baseline entry consistent with the mrepo initialization change.

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