fix: count worktree branches in git extension numbering

[luohui1]

Summary

• Strip Git's + worktree marker when the bundled Git extension scans git branch -a for sequential feature prefixes.
• Apply marker normalization in Bash and PowerShell branch-creation scripts without stripping literal leading + characters from valid branch names.
• Add regression coverage for sibling worktree branches and Bash literal-plus branch prefixes.

Root Cause

git branch -a prefixes branches checked out in another worktree with +. The Git extension only removed * and spaces before extracting numeric prefixes, so sibling worktree branches were ignored and the next generated feature branch could reuse an existing prefix.

A review also pointed out that the initial Bash normalization stripped any leading +, including literal + characters that Git allows inside branch names. The Bash path now strips only the git branch marker column when it is followed by whitespace.

Validation

• uv run --extra test pytest tests/extensions/git/test_git_extension.py::TestCreateFeaturePowerShell::test_dry_run_counts_branches_checked_out_in_worktrees -q (red before fix: produced 001-next; green after fix)
• uv run --extra test pytest tests/extensions/git/test_git_extension.py -q (23 passed, 27 skipped on Windows)
• uv run --extra test pytest tests/test_timestamp_branches.py -q (18 passed, 52 skipped on Windows)
• WSL Bash smoke for create-new-feature-branch.sh --json --dry-run with sibling worktree 007-worktree-feature produced {"BRANCH_NAME":"008-next","FEATURE_NUM":"008","DRY_RUN":true}
• Review fix: uv run --extra test pytest tests/extensions/git/test_git_extension.py::TestCreateFeatureBash::test_dry_run_counts_branches_checked_out_in_worktrees tests/extensions/git/test_git_extension.py::TestCreateFeatureBash::test_dry_run_preserves_literal_plus_branch_prefix tests/extensions/git/test_git_extension.py::TestCreateFeaturePowerShell::test_dry_run_counts_branches_checked_out_in_worktrees -q (1 passed, 2 skipped on Windows)
• uvx ruff check src/ tests/extensions/git/test_git_extension.py
• uvx ruff check tests/extensions/git/test_git_extension.py
• git diff --check

Full uv run --extra test pytest -q was attempted locally but timed out after 15 minutes before producing a pass/fail summary, so it is not claimed as passing here.

AI Assistance

Prepared with AI assistance and manually reviewed before submission.

Closes #1066

[Copilot]

⚠️ Not ready to approve

The Bash branch-name normalization is currently too broad and can incorrectly strip a leading + that is part of a legitimate branch name, causing mis-numbering in that edge case.

Pull request overview

Fixes sequential feature-branch numbering when existing branches are checked out in sibling git worktrees (which git branch -a marks with a leading +), preventing prefix reuse (e.g., generating 001-* again when 001-* already exists elsewhere).

Changes:

• Normalize git branch -a output to strip the worktree + marker before extracting numeric prefixes (Bash + PowerShell).
• Add regression tests that create a sibling worktree on a 007-* branch and assert the next generated branch is 008-*.

File summaries

File	Description
tests/extensions/git/test_git_extension.py	Adds worktree-based regression coverage for both Bash and PowerShell branch creation scripts.
extensions/git/scripts/powershell/create-new-feature-branch.ps1	Strips + worktree markers (alongside *) when cleaning branch names for prefix scanning.
extensions/git/scripts/bash/create-new-feature-branch.sh	Strips + worktree markers when cleaning branch names for prefix scanning (needs a small tweak noted in review).

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 1

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[Copilot]

✅ Ready to approve

The change is narrowly scoped, fixes the stated root cause, and is backed by focused regression tests for both worktree and literal-plus edge cases.

Note: this review does not count toward required approvals for merging.

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 0 new

Note

Your feedback helps us improve the quality of this feature.
Please use 👍 or 👎 to tell us whether this assessment is correct.

[mnriem]

Thank you!