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fix(git): validate refs before worktree creation and improve main branch detection #61

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Merged
johannesjo merged 1 commit into from
Apr 12, 2026
+36 −1
Merged

fix(git): validate refs before worktree creation and improve main branch detection #61

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37 changes: 36 additions & 1 deletion electron/ipc/git.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,18 @@ async function remoteTrackingRefExists(repoRoot: string, branch: string): Promis
}
}

/** Check whether a local branch ref exists. */
async function localBranchExists(repoRoot: string, branch: string): Promise<boolean> {
try {
await exec('git', ['rev-parse', '--verify', `refs/heads/${branch}`], {
cwd: repoRoot,
});
return true;
} catch {
return false;
}
}

async function detectMainBranchUncached(repoRoot: string): Promise<string> {
// Try remote HEAD reference first
const branch = await resolveOriginHead(repoRoot);
Expand All @@ -168,10 +180,13 @@ async function detectMainBranchUncached(repoRoot: string): Promise<string> {
}
}

// Check common default branch names
// Check common default branch names (remote-tracking first, then local)
for (const candidate of ['main', 'master']) {
if (await remoteTrackingRefExists(repoRoot, candidate)) return candidate;
}
for (const candidate of ['main', 'master']) {
if (await localBranchExists(repoRoot, candidate)) return candidate;
}
Comment on lines +183 to +189
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Copilot AI Apr 9, 2026

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New behavior is introduced in detectMainBranchUncached() (fallback to local refs/heads/*) and createWorktree() (start-point ref validation + custom error messages), but there are no tests in this PR exercising these paths. Since electron/ipc/git.test.ts already mocks git commands, add targeted tests for: (1) no-remote + local main exists => returns main; (2) createWorktree with missing baseBranch in a non-empty repo => throws the new “Branch … does not exist” error; (3) empty repo => throws the new “no commits” error.

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// Empty repo (no commits yet) — use configured default branch or fall back to "main"
try {
Expand Down Expand Up @@ -393,6 +408,26 @@ export async function createWorktree(
}
}

// Validate the start-point ref exists before attempting worktree creation
const startRef = baseBranch || 'HEAD';
try {
await exec('git', ['rev-parse', '--verify', startRef], { cwd: repoRoot });
} catch {
const isEmptyRepo = await exec('git', ['rev-list', '-n1', '--all'], { cwd: repoRoot })
.then(({ stdout }) => !stdout.trim())
.catch(() => true);
Comment on lines +416 to +418
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Copilot AI Apr 9, 2026

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The isEmptyRepo detection treats any failure of git rev-list -n1 --all as an empty repository (catch(() => true)), which can mask other problems (e.g., repoRoot not being a git repo, missing permissions, or git not available) and surface a misleading “no commits” error. Consider only classifying as empty when the command succeeds and returns no output; otherwise rethrow (or throw a more specific “not a git repository”/original git error).

Suggested change
const isEmptyRepo = await exec('git', ['rev-list', '-n1', '--all'], { cwd: repoRoot })
.then(({ stdout }) => !stdout.trim())
.catch(() => true);
let isEmptyRepo = false;
try {
const { stdout } = await exec('git', ['rev-list', '-n1', '--all'], { cwd: repoRoot });
isEmptyRepo = !stdout.trim();
} catch (err) {
throw err;
}

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if (isEmptyRepo) {
throw new Error(
'Cannot create a worktree in a repository with no commits. ' +
'Please make an initial commit first.',
);
}
throw new Error(
`Branch "${startRef}" does not exist. ` +
'Please select a valid base branch or create the branch first.',
);
}

// Create fresh worktree with new branch
const worktreeArgs = ['worktree', 'add', '-b', branchName, worktreePath];
if (baseBranch) worktreeArgs.push(baseBranch);
Expand Down