Fix rename_worktree refusing every freshly created worktree

src/main/worktree-rename.integration.test.ts

@@ -0,0 +1,130 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest'
+import fs from 'fs'
+import os from 'os'
+import { execFileSync } from 'child_process'
+import { join } from 'path'
+
+import { renameWorktreeBranch } from './worktree'
+
+// REAL git, no mocks. A freshly created worktree tracks the base it was cut
+// from (origin/main) thanks to git's default branch.autoSetupMerge, which is
+// NOT the same thing as having been published.
+
+function git(cwd: string, ...args: string[]): string {
+  return execFileSync('git', args, { cwd, stdio: 'pipe' }).toString()
+}
+
+let tmp: string
+let clone: string
+
+beforeAll(() => {
+  tmp = fs.mkdtempSync(join(os.tmpdir(), 'wt-rename-'))
+
+  const seed = join(tmp, 'seed')
+  fs.mkdirSync(seed)
+  git(seed, 'init', '-q', '-b', 'main')
+  git(seed, 'config', 'user.email', 't@t.t')
+  git(seed, 'config', 'user.name', 'T')
+  fs.writeFileSync(join(seed, 'seed.txt'), 'seed\n')
+  git(seed, 'add', '.')
+  git(seed, 'commit', '-q', '-m', 'seed')
+
+  const origin = join(tmp, 'origin.git')
+  execFileSync('git', ['clone', '-q', '--bare', seed, origin], { stdio: 'pipe' })
+
+  clone = join(tmp, 'clone')
+  execFileSync('git', ['clone', '-q', origin, clone], { stdio: 'pipe' })
+  git(clone, 'config', 'user.email', 't@t.t')
+  git(clone, 'config', 'user.name', 'T')
+})
+
+afterAll(() => {
+  fs.rmSync(tmp, { recursive: true, force: true })
+})
+
+/** A worktree cut from origin/main, exactly as addWorktree creates one. */
+function makeWorktree(branch: string): string {
+  const path = join(tmp, branch.replace(/\//g, '-'))
+  git(clone, 'worktree', 'add', '-q', path, '-b', branch, 'origin/main')
+  return path
+}
+
+function upstreamOf(cwd: string): string {
+  try {
+    return git(cwd, 'rev-parse', '--abbrev-ref', '--symbolic-full-name', '@{upstream}').trim()
+  } catch {
+    return ''
+  }
+}
+
+function headOf(cwd: string): string {
+  return git(cwd, 'symbolic-ref', '--short', 'HEAD').trim()
+}
+
+describe('renameWorktreeBranch (real git)', () => {
+  it('renames a fresh worktree branch even though it tracks origin/main', async () => {
+    const worktree = makeWorktree('fresh')
+    expect(upstreamOf(worktree)).toBe('origin/main')
+
+    const result = await renameWorktreeBranch(worktree, 'fresh-renamed')
+
+    expect(result).toEqual({
+      ok: true,
+      oldBranch: 'fresh',
+      branch: 'fresh-renamed',
+      renamed: true
+    })
+    expect(headOf(worktree)).toBe('fresh-renamed')
+  })
+
+  it('renames a branch whose name contains a slash', async () => {
+    const worktree = makeWorktree('fix/login')
+
+    const result = await renameWorktreeBranch(worktree, 'fix/logout')
+
+    expect(result.ok).toBe(true)
+    expect(headOf(worktree)).toBe('fix/logout')
+  })
+
+  it('refuses once the branch has been pushed with -u', async () => {
+    const worktree = makeWorktree('pushed-tracking')
+    git(worktree, 'push', '-q', '-u', 'origin', 'pushed-tracking')
+
+    const result = await renameWorktreeBranch(worktree, 'pushed-tracking-renamed')
+
+    expect(result.ok).toBe(false)
+    if (!result.ok) expect(result.error).toContain('origin/pushed-tracking')
+    expect(headOf(worktree)).toBe('pushed-tracking')
+  })
+
+  it('refuses after a plain push that left the upstream on origin/main', async () => {
+    const worktree = makeWorktree('pushed-plain')
+    git(worktree, 'push', '-q', 'origin', 'pushed-plain')
+    expect(upstreamOf(worktree)).toBe('origin/main')
+
+    const result = await renameWorktreeBranch(worktree, 'pushed-plain-renamed')
+
+    expect(result.ok).toBe(false)
+    expect(headOf(worktree)).toBe('pushed-plain')
+  })
+
+  it('refuses a published branch whose name contains a slash', async () => {
+    const worktree = makeWorktree('feat/published')
+    git(worktree, 'push', '-q', '-u', 'origin', 'feat/published')
+
+    const result = await renameWorktreeBranch(worktree, 'feat/renamed')
+
+    expect(result.ok).toBe(false)
+    if (!result.ok) expect(result.error).toContain('origin/feat/published')
+  })
+
+  it('reports the existing branch by name when the target is taken', async () => {
+    const worktree = makeWorktree('collides')
+    git(clone, 'branch', 'taken')
+
+    const result = await renameWorktreeBranch(worktree, 'taken')
+
+    expect(result.ok).toBe(false)
+    if (!result.ok) expect(result.error).toContain('"taken" already exists')
+  })
+})

src/main/worktree.ts

@@ -1290,6 +1290,37 @@ export type RenameBranchResult =
   | { ok: true; oldBranch: string; branch: string; renamed: boolean }
   | { ok: false; error: string }
 
+/**
+ * The remote ref `branch` would keep pushing to after a rename, or '' if it
+ * has never been pushed.
+ *
+ * A tracked upstream on its own does NOT mean published: git's default
+ * `branch.autoSetupMerge` points a branch cut from `origin/main` at
+ * `origin/main`, so every freshly created worktree looks tracked. What
+ * matters is whether a remote ref named after *this branch* exists — that's
+ * the ref a renamed branch would silently keep pushing to. The upstream is
+ * only considered when it names this branch (covers a branch whose remote
+ * counterpart was deleted, which `git push` would recreate under the old
+ * name).
+ */
+async function publishedRemoteRef(worktreePath: string, branch: string): Promise<string> {
+  const remoteRef = await execGitRead(
+    ['for-each-ref', '--format=%(refname:short)', `refs/remotes/*/${branch}`],
+    { cwd: worktreePath }
+  )
+    .then(({ stdout }) => stdout.trim().split('\n')[0]?.trim() || '')
+    .catch(() => '')
+  if (remoteRef) return remoteRef
+
+  const upstream = await execGitRead(
+    ['rev-parse', '--abbrev-ref', '--symbolic-full-name', '@{upstream}'],
+    { cwd: worktreePath }
+  )
+    .then(({ stdout }) => stdout.trim())
+    .catch(() => '')
+  return upstream.endsWith(`/${branch}`) ? upstream : ''
+}
+
 /**
  * Rename the branch a worktree has checked out (`git branch -m`). The
  * directory on disk keeps its original name — it's the key every other
@@ -1317,17 +1348,12 @@ export async function renameWorktreeBranch(
     return { ok: true, oldBranch, branch: newBranch, renamed: false }
   }
 
-  const upstream = await execGitRead(
-    ['rev-parse', '--abbrev-ref', '--symbolic-full-name', '@{upstream}'],
-    { cwd: worktreePath }
-  )
-    .then(({ stdout }) => stdout.trim())
-    .catch(() => '')
-  if (upstream) {
+  const remoteRef = await publishedRemoteRef(worktreePath, oldBranch)
+  if (remoteRef) {
     return {
       ok: false,
       error:
-        `branch "${oldBranch}" is already published (tracking ${upstream}) — renaming it locally ` +
+        `branch "${oldBranch}" is already published (pushed to ${remoteRef}) — renaming it locally ` +
         `would leave it pushing to the old remote branch. Set a display alias instead.`
     }
   }