Claude Code's EnterWorktree tool converts "/" to "+" when generating
branch names from worktree names (e.g. EnterWorktree("feat/foo") creates
branch "worktree-feat+foo"). The strict whitelist in validateBranchName
rejected these names, causing claude-code-action to fail on any PR opened
from an EnterWorktree-generated branch.
Since all git calls use execFileSync (not shell interpolation), "+" carries
no command injection risk — the same rationale used for allowing "#".
Git itself permits "+" in branch names per git-check-ref-format.
Fixes: https://github.com/anthropics/claude-code-action/issues/1244
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
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