fix: allow + in branch names (generated by Claude Code EnterWorktree) (#1248)

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: #1244

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: awakia

src/github/operations/branch.ts

@@ -58,14 +58,16 @@ export function validateBranchName(branchName: string): void {
     );
   }
 
-  // Strict whitelist pattern: alphanumeric start, then alphanumeric/slash/hyphen/underscore/period/hash.
+  // Strict whitelist pattern: alphanumeric start, then alphanumeric/slash/hyphen/underscore/period/hash/plus.
   // # is valid per git-check-ref-format and commonly used in branch names like "fix/#123-description".
-  // All git calls use execFileSync (not shell interpolation), so # carries no injection risk.
-  const validPattern = /^[a-zA-Z0-9][a-zA-Z0-9/_.#-]*$/;
+  // + is valid per git-check-ref-format and generated by Claude Code's EnterWorktree tool when
+  //   converting worktree names containing "/" (e.g. "feat/foo" becomes "worktree-feat+foo").
+  // All git calls use execFileSync (not shell interpolation), so neither # nor + carries injection risk.
+  const validPattern = /^[a-zA-Z0-9][a-zA-Z0-9/_.#+-]*$/;
 
   if (!validPattern.test(branchName)) {
     throw new Error(
-      `Invalid branch name: "${branchName}". Branch names must start with an alphanumeric character and contain only alphanumeric characters, forward slashes, hyphens, underscores, periods, or hashes (#).`,
+      `Invalid branch name: "${branchName}". Branch names must start with an alphanumeric character and contain only alphanumeric characters, forward slashes, hyphens, underscores, periods, hashes (#), or plus signs (+).`,
     );
   }
 

test/validate-branch-name.test.ts

@@ -45,6 +45,16 @@ describe("validateBranchName", () => {
       ).not.toThrow();
       expect(() => validateBranchName("fix/issue-#42")).not.toThrow();
     });
+
+    it("should accept branch names containing + (generated by Claude Code EnterWorktree)", () => {
+      // EnterWorktree converts "/" in worktree names to "+" when generating branch names.
+      // e.g. EnterWorktree("feat/skill-consolidation") → branch "worktree-feat+skill-consolidation"
+      expect(() =>
+        validateBranchName("worktree-feat+skill-consolidation"),
+      ).not.toThrow();
+      expect(() => validateBranchName("fix+issue-123")).not.toThrow();
+      expect(() => validateBranchName("feature+new-thing")).not.toThrow();
+    });
   });
 
   describe("command injection attempts", () => {