perf(git): answer remote-URL questions from one subprocess, not one per remote (#18158)

Four copies of the same loop ran `git remote` and then a serial `git remote get-url <name>` per remote to answer "which remote has this URL". On a repo with 58 remotes that is 59 subprocesses -- measured at 1083 ms -- for one question, and worktree create asks it several times. `git remote -v` answers for every remote from one child, reporting the same insteadOf-expanded first fetch URL `get-url` prints. The batched `cat-file --batch-check` branch-conflict probe decides from stdout, but its WSL route was unfenced, so a login-shell fallback printed the distro banner onto the stream it parses. That broke the one-line-per-ref contract, made every batch undecided, and fell straight back to one `show-ref` per remote -- the cost the batch exists to remove. Measured at 58 remotes / 4346 branches, spawns and wall time: push-target remote scan 59 -> 1 (1083 ms -> 8 ms) branch-conflict probe 60 -> 3 (984 ms -> 43 ms) configured push target 123 -> 6 (2707 ms -> 157 ms)
2026-09-22 00:02:31 +00:00 · 2026-09-02 12:53:48 -07:00
parent 1d94ebee3f
commit 104f9655e4
18 changed files with 841 additions and 128 deletions
@@ -157,7 +157,11 @@ export async function probeAnyExactRefBatched(
  } catch {
    return { found: false, unknown: true }
  }
-  const lines = stdout.split('\n').filter((line) => line.trim().length > 0)
+  // Trim per line so a CRLF-translating host's `\r` does not become part of the type.
+  const lines = stdout
+    .split('\n')
+    .map((line) => line.trim())
+    .filter((line) => line.length > 0)
  // One line per input, in order; a short read means the batch never answered for the rest.
  if (lines.length !== safeRefs.length) {
    return { found: false, unknown: true }
@@ -193,6 +193,17 @@ describe('git remote operations', () => {
      if (args[0] === 'remote' && args[1] === 'get-url' && args[2] === 'pr-pynickle-orca') {
        return { stdout: 'https://github.com/pynickle/orca.git\n', stderr: '' }
      }
+      if (args[0] === 'remote' && args[1] === '-v') {
+        return {
+          stdout: [
+            'origin\thttps://github.com/stablyai/orca.git (fetch)',
+            'origin\thttps://github.com/stablyai/orca.git (push)',
+            'pr-pynickle-orca\thttps://github.com/pynickle/orca.git (fetch)',
+            'pr-pynickle-orca\thttps://github.com/pynickle/orca.git (push)'
+          ].join('\n'),
+          stderr: ''
+        }
+      }
      if (args[0] === 'remote') {
        return { stdout: 'origin\npr-pynickle-orca\n', stderr: '' }
      }
@@ -207,6 +218,54 @@ describe('git remote operations', () => {
    )
  })

+  // Regression: normalizing a URL-valued push remote used to run `git remote` and then a
+  // serial `git remote get-url` per remote -- 59 subprocesses on a 58-remote repo.
+  it('normalizes a URL-valued push remote from one remote table read at 58 remotes', async () => {
+    const remotes = [
+      { name: 'origin', url: 'https://github.com/stablyai/orca.git' },
+      ...Array.from({ length: 56 }, (_, index) => ({
+        name: `pr-user${index}-orca`,
+        url: `https://github.com/user${index}/orca.git`
+      })),
+      { name: 'pr-pynickle-orca', url: 'https://github.com/pynickle/orca.git' }
+    ]
+    gitExecFileAsyncMock.mockImplementation(async (args: string[]) => {
+      if (args[0] === 'symbolic-ref') {
+        return { stdout: 'imp/chinese-translation\n', stderr: '' }
+      }
+      if (args[0] === 'config' && args.includes('branch.imp/chinese-translation.remote')) {
+        return { stdout: 'https://github.com/pynickle/orca.git\n', stderr: '' }
+      }
+      if (args[0] === 'config' && args.includes('branch.imp/chinese-translation.merge')) {
+        return { stdout: 'refs/heads/imp/chinese-translation\n', stderr: '' }
+      }
+      if (args[0] === 'config') {
+        throw new Error(`config key is not set: ${args.join(' ')}`)
+      }
+      if (args[0] === 'remote' && args[1] === '-v') {
+        return {
+          stdout: remotes
+            .flatMap(({ name, url }) => [`${name}\t${url} (fetch)`, `${name}\t${url} (push)`])
+            .join('\n'),
+          stderr: ''
+        }
+      }
+      if (args[0] === 'remote') {
+        throw new Error(`unexpected remote scan: ${args.join(' ')}`)
+      }
+      return { stdout: '', stderr: '' }
+    })
+
+    await gitPush('/repo', false)
+
+    const remoteReads = gitExecFileAsyncMock.mock.calls.filter(([args]) => args[0] === 'remote')
+    expect(remoteReads.map(([args]) => args)).toEqual([['remote', '-v']])
+    expect(gitExecFileAsyncMock).toHaveBeenLastCalledWith(
+      ['push', '--set-upstream', 'pr-pynickle-orca', 'HEAD:imp/chinese-translation'],
+      { cwd: '/repo' }
+    )
+  })
+
  it('uses an explicit push target even when it differs from the local branch name', async () => {
    gitExecFileAsyncMock
      .mockResolvedValueOnce({ stdout: '', stderr: '' })
@@ -4,6 +4,7 @@ import {
 } from '../../shared/git-remote-error'
 import { resolveEffectiveGitUpstream } from '../../shared/git-effective-upstream'
 import { gitRefTargetsBranchOnRemote } from '../../shared/git-remote-branch-name'
+import { findGitRemoteNameByFetchUrl } from '../../shared/git-remote-url-index'
 import type { GitPushTarget } from '../../shared/worktree/types'
 import type { GitRuntimeOptions } from './git-runtime-options'
 import { gitOptionsForWorktree } from './git-runtime-options'
@@ -84,6 +85,8 @@ type ConfiguredPushRemote = {
  branchRemote: string | null
 }

+// One `git remote -v` instead of `git remote` plus a serial `git remote get-url`
+// per remote; both print the same insteadOf-expanded fetch URL.
 async function findRemoteNameForUrl(
  worktreePath: string,
  remoteUrl: string,
@@ -91,30 +94,13 @@ async function findRemoteNameForUrl(
 ): Promise<string | null> {
  try {
    const { stdout } = await gitExecFileAsync(
-      ['remote'],
+      ['remote', '-v'],
      gitOptionsForWorktree(worktreePath, options)
    )
-    const remotes = stdout
-      .split(/\r?\n/)
-      .map((line) => line.trim())
-      .filter(Boolean)
-    for (const remoteName of remotes) {
-      try {
-        const { stdout: urlStdout } = await gitExecFileAsync(
-          ['remote', 'get-url', remoteName],
-          gitOptionsForWorktree(worktreePath, options)
-        )
-        if (urlStdout.trim() === remoteUrl) {
-          return remoteName
-        }
-      } catch {
-        // Ignore a remote that disappeared or has no fetch URL.
-      }
-    }
+    return findGitRemoteNameByFetchUrl(stdout, (candidateUrl) => candidateUrl === remoteUrl)
  } catch {
    return null
  }
-  return null
 }

 async function normalizePushRemote(
@@ -141,11 +127,17 @@ async function getConfiguredPushRemote(
  if (!remote) {
    return null
  }
+  const normalizedRemote = await normalizePushRemote(worktreePath, remote, options)
+  // The two usually name the same URL; resolving it twice reads the remote table twice.
+  if (!branchRemote) {
+    return { remote: normalizedRemote, branchRemote: null }
+  }
  return {
-    remote: await normalizePushRemote(worktreePath, remote, options),
-    branchRemote: branchRemote
-      ? await normalizePushRemote(worktreePath, branchRemote, options)
-      : null
+    remote: normalizedRemote,
+    branchRemote:
+      branchRemote === remote
+        ? normalizedRemote
+        : await normalizePushRemote(worktreePath, branchRemote, options)
  }
 }

@@ -0,0 +1,102 @@
+// Why: the batched `cat-file --batch-check` conflict probe decides from stdout, so a
+// WSL login-shell fallback that prints the distro banner onto that stream desynchronizes
+// the one-line-per-ref contract. Every batch then came back undecided and fell through to
+// one `show-ref` subprocess per remote -- the cost the batch exists to remove. These tests
+// pin the fence request and the resulting subprocess count at 58 remotes.
+
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { gitExecFileAsyncMock } = vi.hoisted(() => ({ gitExecFileAsyncMock: vi.fn() }))
+
+vi.mock('./runner', () => ({ gitExecFileAsync: gitExecFileAsyncMock }))
+
+import { getBranchConflictKind } from './repo-branch-conflict'
+
+const REMOTES = Array.from({ length: 58 }, (_, index) => `r${index}`)
+const BRANCH = 'user/feature'
+const WSL_BANNER =
+  'Welcome to Ubuntu 24.04.1 LTS (GNU/Linux 5.15.167.4-microsoft-standard-WSL2 x86_64)\n' +
+  'To run a command as administrator (user "root"), use "sudo <command>".\n'
+
+type GitExecOptions = { stdin?: string; captureWslLoginShellOutput?: boolean }
+
+/**
+ * Stand-in for a WSL-routed runner: the login shell prepends its banner to stdout unless
+ * the caller asked for the fenced form, which slices the payload back out.
+ */
+function installLoginShellRunner(): { argv: string[][] } {
+  const argv: string[][] = []
+  gitExecFileAsyncMock.mockImplementation(async (args: string[], options: GitExecOptions = {}) => {
+    argv.push(args)
+    if (args[0] === 'rev-parse') {
+      throw new Error('local branch is absent')
+    }
+    if (args[0] === 'remote') {
+      return { stdout: `${WSL_BANNER}${REMOTES.join('\n')}\n`, stderr: '' }
+    }
+    if (args[0] === 'show-ref') {
+      throw Object.assign(new Error('missing ref'), { code: 1, stderr: '' })
+    }
+    if (args[0] === 'cat-file') {
+      const payload = `${(options.stdin ?? '')
+        .split('\n')
+        .filter(Boolean)
+        .map((ref) => `${ref} missing`)
+        .join('\n')}\n`
+      return {
+        stdout: options.captureWslLoginShellOutput ? payload : `${WSL_BANNER}${payload}`,
+        stderr: ''
+      }
+    }
+    throw new Error(`unexpected git command: ${args.join(' ')}`)
+  })
+  return { argv }
+}
+
+function countSubcommand(argv: readonly string[][], subcommand: string): number {
+  return argv.filter((args) => args[0] === subcommand).length
+}
+
+describe('getBranchConflictKind batched remote probe', () => {
+  beforeEach(() => {
+    gitExecFileAsyncMock.mockReset()
+  })
+
+  it('asks the WSL login shell to fence the batch payload it parses', async () => {
+    installLoginShellRunner()
+
+    await getBranchConflictKind('/repo', BRANCH)
+
+    const batchCall = gitExecFileAsyncMock.mock.calls.find(([args]) => args[0] === 'cat-file')
+    expect(batchCall?.[1]).toMatchObject({ captureWslLoginShellOutput: true })
+  })
+
+  it('answers from one batched subprocess instead of one show-ref per remote', async () => {
+    const { argv } = installLoginShellRunner()
+
+    await expect(getBranchConflictKind('/repo', BRANCH)).resolves.toBeNull()
+
+    expect(countSubcommand(argv, 'cat-file')).toBe(1)
+    expect(countSubcommand(argv, 'show-ref')).toBe(0)
+  })
+
+  it('still falls back to per-ref probes when the batch itself fails', async () => {
+    gitExecFileAsyncMock.mockImplementation(async (args: string[]) => {
+      if (args[0] === 'rev-parse') {
+        throw new Error('local branch is absent')
+      }
+      if (args[0] === 'remote') {
+        return { stdout: `${REMOTES.join('\n')}\n`, stderr: '' }
+      }
+      if (args[0] === 'cat-file') {
+        throw new Error('cat-file is unavailable on this host')
+      }
+      if (args[0] === 'show-ref') {
+        return { stdout: '', stderr: '' }
+      }
+      throw new Error(`unexpected git command: ${args.join(' ')}`)
+    })
+
+    await expect(getBranchConflictKind('/repo', BRANCH)).resolves.toBe('remote')
+  })
+})
@@ -147,10 +147,12 @@ export function getBranchConflictKind(
  const execOptions = gitExecOptions(path, options)
  const runLocalGit = (
    argv: string[],
-    commandOptions?: ExactRefProbeExecOptions & { stdin?: string }
+    commandOptions?: ExactRefProbeExecOptions & { stdin?: string },
+    captureWslLoginShellOutput = false
  ): Promise<{ stdout: string }> =>
    gitExecFileAsync(argv, {
      ...execOptions,
+      ...(captureWslLoginShellOutput ? { captureWslLoginShellOutput: true } : {}),
      ...(commandOptions?.maxBuffer === undefined ? {} : { maxBuffer: commandOptions.maxBuffer }),
      ...(commandOptions?.timeoutMs === undefined ? {} : { timeout: commandOptions.timeoutMs }),
      ...(commandOptions?.stdin === undefined ? {} : { stdin: commandOptions.stdin })
@@ -160,7 +162,13 @@ export function getBranchConflictKind(
    branchName,
    allowedBaseRef,
    {},
-    (argv, commandOptions) => runLocalGit(argv, commandOptions)
+    // Why fenced: the batch decides from stdout, and a WSL login-shell fallback writes
+    // the distro's rc/motd banner to that same stream. The extra lines break the
+    // one-line-per-ref contract, so every batch came back undecided and fell through to
+    // one `show-ref` subprocess per remote -- the exact cost the batch exists to remove.
+    // `show-ref --verify --quiet` prints nothing and is read by exit code, so it needs
+    // no fence; the capture wrapper preserves the payload's exit status either way.
+    (argv, commandOptions) => runLocalGit(argv, commandOptions, true)
  )
 }

@@ -363,6 +363,16 @@ describe('getUpstreamStatus', () => {
      if (args[0] === 'remote' && args[1] === 'get-url' && args[2] === 'pr-pynickle-orca') {
        return Promise.resolve({ stdout: 'https://github.com/pynickle/orca.git\n' })
      }
+      if (args[0] === 'remote' && args[1] === '-v') {
+        return Promise.resolve({
+          stdout: [
+            'origin\thttps://github.com/stablyai/orca.git (fetch)',
+            'origin\thttps://github.com/stablyai/orca.git (push)',
+            'pr-pynickle-orca\thttps://github.com/pynickle/orca.git (fetch)',
+            'pr-pynickle-orca\thttps://github.com/pynickle/orca.git (push)'
+          ].join('\n')
+        })
+      }
      if (args[0] === 'remote') {
        return Promise.resolve({ stdout: 'origin\npr-pynickle-orca\n' })
      }
@@ -13,7 +13,7 @@ import { listWorktrees } from '../git/worktree'
 import type { SshGitProvider } from '../providers/ssh-git-provider'
 import type { GitPushTarget } from '../../shared/worktree/types'
 import { WORKTREE_ID_SEPARATOR, worktreeIdComparisonKey } from '../../shared/worktree/id'
-import { iterateProcessOutputLines } from '../../shared/process-output-field-scanner'
+import { parseGitRemoteFetchUrls } from '../../shared/git-remote-url-index'
 import {
  findWorktreeMetaReferencingRemote,
  hasBranchConfigUsingRemote,
@@ -44,26 +44,9 @@ async function listPrRemoteCandidates(
  } catch {
    return []
  }
-  const candidates = new Map<string, string>()
-  for (const line of iterateProcessOutputLines(stdout)) {
-    const parsed = parseRemoteVerboseLine(line)
-    if (parsed?.direction === 'fetch' && isOrcaGeneratedPrRemoteName(parsed.name)) {
-      candidates.set(parsed.name, parsed.url)
-    }
-  }
-  return [...candidates.entries()].map(([name, url]) => ({ name, url }))
-}
-
-function parseRemoteVerboseLine(
-  line: string
-): { name: string; url: string; direction: 'fetch' | 'push' } | null {
-  const tabIndex = line.indexOf('\t')
-  if (tabIndex === -1) {
-    return null
-  }
-  const name = line.slice(0, tabIndex)
-  const match = /^(.*) \((fetch|push)\)$/.exec(line.slice(tabIndex + 1).trim())
-  return match ? { name, url: match[1], direction: match[2] as 'fetch' | 'push' } : null
+  return [...parseGitRemoteFetchUrls(stdout)]
+    .filter(([name]) => isOrcaGeneratedPrRemoteName(name))
+    .map(([name, url]) => ({ name, url }))
 }

 async function shouldReclaimPrRemote(
@@ -0,0 +1,178 @@
+// Why: `findRemoteForUrl` used to run `git remote` and then one serial
+// `git remote get-url` per remote. These tests pin both halves of the fix: the
+// subprocess count at 58 remotes, and result-for-result parity with the old scan
+// across the remote shapes a real repo produces.
+
+import { describe, expect, it } from 'vitest'
+import { parseGitHubOwnerRepo } from '../github/gh-utils'
+import { findRemoteForUrl } from './worktree-push-target-setup'
+import type { GitRemoteExec } from './worktree-push-target-cleanup'
+
+const SSH_FORK = 'git@github.com:contributor/orca.git'
+const HTTPS_FORK = 'https://github.com/contributor/orca.git'
+const GITLAB_FORK = 'https://gitlab.com/contributor/orca.git'
+const UPSTREAM = 'https://github.com/stablyai/orca.git'
+
+type RemoteRow = { name: string; fetchUrl: string; pushUrl?: string }
+
+type CountingExec = GitRemoteExec & { spawns: string[][] }
+
+function makeExec(remotes: readonly RemoteRow[]): CountingExec {
+  const spawns: string[][] = []
+  const exec: GitRemoteExec = async (args: string[]) => {
+    spawns.push(args)
+    if (args[0] === 'remote' && args.length === 1) {
+      return { stdout: `${remotes.map((remote) => remote.name).join('\n')}\n` }
+    }
+    if (args[0] === 'remote' && args[1] === '-v') {
+      return {
+        stdout: remotes
+          .flatMap((remote) => [
+            `${remote.name}\t${remote.fetchUrl} (fetch)`,
+            `${remote.name}\t${remote.pushUrl ?? remote.fetchUrl} (push)`
+          ])
+          .join('\n')
+      }
+    }
+    if (args[0] === 'remote' && args[1] === 'get-url') {
+      const match = remotes.find((remote) => remote.name === args[2])
+      if (!match) {
+        throw new Error(`No such remote ${args[2]}`)
+      }
+      return { stdout: `${match.fetchUrl}\n` }
+    }
+    throw new Error(`unexpected git command: ${args.join(' ')}`)
+  }
+  return Object.assign(exec, { spawns })
+}
+
+/** The pre-fix scan, kept as the oracle the batched form must reproduce exactly. */
+async function findRemoteForUrlPerRemote(
+  execGit: GitRemoteExec,
+  repoPath: string,
+  remoteUrl: string
+): Promise<string | null> {
+  const target = parseGitHubOwnerRepo(remoteUrl)
+  try {
+    const { stdout } = await execGit(['remote'], repoPath)
+    for (const remote of stdout
+      .split(/\r?\n/)
+      .map((line) => line.trim())
+      .filter(Boolean)) {
+      try {
+        const { stdout: urlStdout } = await execGit(['remote', 'get-url', remote], repoPath)
+        const candidateUrl = urlStdout.trim()
+        const candidate = parseGitHubOwnerRepo(candidateUrl)
+        if (
+          target &&
+          candidate &&
+          target.owner.toLowerCase() === candidate.owner.toLowerCase() &&
+          target.repo.toLowerCase() === candidate.repo.toLowerCase()
+        ) {
+          return remote
+        }
+        if (candidateUrl === remoteUrl) {
+          return remote
+        }
+      } catch {
+        // Ignore a remote that disappeared or has no fetch URL.
+      }
+    }
+  } catch {
+    return null
+  }
+  return null
+}
+
+const fiftyEightRemotes: RemoteRow[] = [
+  { name: 'origin', fetchUrl: UPSTREAM },
+  ...Array.from({ length: 56 }, (_, index) => ({
+    name: `pr-user${index}-orca`,
+    fetchUrl: `https://github.com/user${index}/orca.git`
+  })),
+  { name: 'pr-contributor-orca', fetchUrl: SSH_FORK }
+]
+
+const matrix: { name: string; remotes: RemoteRow[]; lookupUrl: string }[] = [
+  { name: 'no remotes', remotes: [], lookupUrl: SSH_FORK },
+  {
+    name: 'one matching remote',
+    remotes: [{ name: 'origin', fetchUrl: SSH_FORK }],
+    lookupUrl: SSH_FORK
+  },
+  {
+    name: 'one non-matching remote',
+    remotes: [{ name: 'origin', fetchUrl: UPSTREAM }],
+    lookupUrl: SSH_FORK
+  },
+  { name: '58 remotes, match last', remotes: fiftyEightRemotes, lookupUrl: SSH_FORK },
+  {
+    name: '58 remotes, no match',
+    remotes: fiftyEightRemotes,
+    lookupUrl: 'https://github.com/nobody/other.git'
+  },
+  {
+    name: 'duplicate URLs on two remotes',
+    remotes: [
+      { name: 'origin', fetchUrl: UPSTREAM },
+      { name: 'fork-a', fetchUrl: SSH_FORK },
+      { name: 'fork-b', fetchUrl: SSH_FORK }
+    ],
+    lookupUrl: SSH_FORK
+  },
+  {
+    name: 'fetch and push URLs differ',
+    remotes: [{ name: 'split', fetchUrl: SSH_FORK, pushUrl: HTTPS_FORK }],
+    lookupUrl: SSH_FORK
+  },
+  {
+    name: 'SSH-form lookup against an HTTPS-form remote',
+    remotes: [
+      { name: 'origin', fetchUrl: UPSTREAM },
+      { name: 'fork', fetchUrl: HTTPS_FORK }
+    ],
+    lookupUrl: SSH_FORK
+  },
+  {
+    name: 'HTTPS-form lookup against an SSH-form remote',
+    remotes: [
+      { name: 'origin', fetchUrl: UPSTREAM },
+      { name: 'fork', fetchUrl: SSH_FORK }
+    ],
+    lookupUrl: HTTPS_FORK
+  },
+  {
+    name: 'non-GitHub provider matches only on the exact URL',
+    remotes: [{ name: 'gitlab-fork', fetchUrl: GITLAB_FORK }],
+    lookupUrl: GITLAB_FORK
+  },
+  {
+    name: 'non-GitHub provider with a different host does not match',
+    remotes: [{ name: 'gitlab-fork', fetchUrl: GITLAB_FORK }],
+    lookupUrl: 'https://bitbucket.org/contributor/orca.git'
+  }
+]
+
+describe('findRemoteForUrl', () => {
+  it.each(matrix)('matches the per-remote scan for $name', async ({ remotes, lookupUrl }) => {
+    const expected = await findRemoteForUrlPerRemote(makeExec(remotes), '/repo', lookupUrl)
+    await expect(findRemoteForUrl(makeExec(remotes), '/repo', lookupUrl)).resolves.toBe(expected)
+  })
+
+  it('answers from one subprocess at 58 remotes instead of one per remote', async () => {
+    const legacyExec = makeExec(fiftyEightRemotes)
+    await findRemoteForUrlPerRemote(legacyExec, '/repo', 'https://github.com/nobody/other.git')
+    expect(legacyExec.spawns).toHaveLength(fiftyEightRemotes.length + 1)
+
+    const exec = makeExec(fiftyEightRemotes)
+    await findRemoteForUrl(exec, '/repo', 'https://github.com/nobody/other.git')
+    expect(exec.spawns).toEqual([['remote', '-v']])
+  })
+
+  it('returns null when the remote table cannot be read', async () => {
+    const failing: GitRemoteExec = async () => {
+      throw new Error('not a git repository')
+    }
+    await expect(findRemoteForUrl(failing, '/repo', SSH_FORK)).resolves.toBeNull()
+  })
+})
@@ -16,6 +16,13 @@ const REPO = '/repo-root'
 const FORK_SSH = 'git@github.com:contributor/orca.git'
 const FORK_HTTPS = 'https://github.com/contributor/orca.git'

+/** Real `git remote -v` shape: a fetch row and a push row per remote, tab-separated. */
+export function renderRemoteVerbose(remotes: Record<string, string>): string {
+  return Object.entries(remotes)
+    .flatMap(([name, url]) => [`${name}\t${url} (fetch)`, `${name}\t${url} (push)`])
+    .join('\n')
+}
+
 // A stateful fake git: `remotes` maps name -> url. `remote add` mutates it so
 // later lookups see the new remote, matching real git behavior. Defaults
 // `symbolic-ref --short HEAD` to a real branch name, since a worktree's HEAD
@@ -31,6 +38,9 @@ function makeRepoExec(
    if (args[0] === 'remote' && args.length === 1) {
      return { stdout: Object.keys(remotes).join('\n'), stderr: '' }
    }
+    if (args[0] === 'remote' && args[1] === '-v' && args.length === 2) {
+      return { stdout: renderRemoteVerbose(remotes), stderr: '' }
+    }
    if (args[0] === 'remote' && args[1] === 'get-url') {
      const url = remotes[args[2]!]
      if (!url) {
@@ -5,53 +5,33 @@
 // repo. The store-aware ownership decision stays with the caller via a predicate.

 import type { GitPushTarget } from '../../shared/worktree/types'
-import { parseGitHubOwnerRepo } from '../github/gh-utils'
-import type { GitRemoteExec } from './worktree-push-target-cleanup'
+import { findGitRemoteNameByFetchUrl } from '../../shared/git-remote-url-index'
+import { sameGitHubRemoteUrl, type GitRemoteExec } from './worktree-push-target-cleanup'
 import {
  buildNarrowForkFetchRefspec,
  ensureRemoteTracksBranchNarrowly
 } from '../git/fork-remote-refspec'

+// One `git remote -v` replaces `git remote` plus a serial `git remote get-url` per
+// remote -- 59 subprocesses at 58 remotes, on every push-target resolution (#17914).
 export async function findRemoteForUrl(
  execGit: GitRemoteExec,
  repoPath: string,
  remoteUrl: string
 ): Promise<string | null> {
-  const target = parseGitHubOwnerRepo(remoteUrl)
  try {
-    const { stdout } = await execGit(['remote'], repoPath)
-    for (const remote of stdout
-      .split(/\r?\n/)
-      .map((line) => line.trim())
-      .filter(Boolean)) {
-      try {
-        const { stdout: urlStdout } = await execGit(['remote', 'get-url', remote], repoPath)
-        const candidateUrl = urlStdout.trim()
-        const candidate = parseGitHubOwnerRepo(candidateUrl)
-        if (
-          target &&
-          candidate &&
-          target.owner.toLowerCase() === candidate.owner.toLowerCase() &&
-          target.repo.toLowerCase() === candidate.repo.toLowerCase()
-        ) {
-          return remote
-        }
-        if (candidateUrl === remoteUrl) {
-          return remote
-        }
-      } catch {
-        // Ignore a remote that disappeared or has no fetch URL.
-      }
-    }
+    const { stdout } = await execGit(['remote', '-v'], repoPath)
+    return findGitRemoteNameByFetchUrl(stdout, (candidateUrl) =>
+      sameGitHubRemoteUrl(candidateUrl, remoteUrl)
+    )
  } catch {
    return null
  }
-  return null
 }

 // O(1) probe used before materializing on demand (push/pull/fetch/fast-forward):
-// a single `remote get-url <name>` avoids the O(remotes) `findRemoteForUrl` scan
-// once a fork remote already exists under its expected name (#17828).
+// a single `remote get-url <name>` skips the whole-remote-table read once a fork
+// remote already exists under its expected name (#17828).
 export async function remoteAlreadyMatchesUrl(
  execGit: GitRemoteExec,
  repoPath: string,
@@ -60,18 +40,7 @@ export async function remoteAlreadyMatchesUrl(
 ): Promise<boolean> {
  try {
    const { stdout } = await execGit(['remote', 'get-url', remoteName], repoPath)
-    const candidateUrl = stdout.trim()
-    if (candidateUrl === remoteUrl) {
-      return true
-    }
-    const target = parseGitHubOwnerRepo(remoteUrl)
-    const candidate = parseGitHubOwnerRepo(candidateUrl)
-    return Boolean(
-      target &&
-      candidate &&
-      target.owner.toLowerCase() === candidate.owner.toLowerCase() &&
-      target.repo.toLowerCase() === candidate.repo.toLowerCase()
-    )
+    return sameGitHubRemoteUrl(stdout.trim(), remoteUrl)
  } catch {
    return false
  }
@@ -553,6 +553,17 @@ describe('materializeWorktreePushTargetRemoteSsh', () => {
        }
        throw new Error('No such remote')
      }
+      if (args[0] === 'remote' && args[1] === '-v') {
+        return {
+          stdout: [
+            'origin\thttps://github.com/stablyai/orca.git (fetch)',
+            'origin\thttps://github.com/stablyai/orca.git (push)',
+            `${SIBLING_REMOTE}\t${FORK_URL} (fetch)`,
+            `${SIBLING_REMOTE}\t${FORK_URL} (push)`
+          ].join('\n'),
+          stderr: ''
+        }
+      }
      if (args[0] === 'remote' && args.length === 1) {
        return { stdout: `origin\n${SIBLING_REMOTE}\n`, stderr: '' }
      }
@@ -46,6 +46,17 @@ function gitForConfig(config: {
      }
      return { stdout: `${config.base ?? ''}\n`, stderr: '' }
    }
+    if (args[0] === 'remote' && args[1] === '-v') {
+      return {
+        stdout: (config.remotes ?? [])
+          .flatMap((name) => {
+            const url = config.remoteUrls?.[name] ?? ''
+            return [`${name}\t${url} (fetch)`, `${name}\t${url} (push)`]
+          })
+          .join('\n'),
+        stderr: ''
+      }
+    }
    if (args[0] === 'remote' && args.length === 1) {
      return { stdout: `${config.remotes?.join('\n') ?? ''}\n`, stderr: '' }
    }
@@ -1,5 +1,6 @@
 import { assertGitPushTargetShape } from '../shared/git-push-target-validation'
 import { gitRefTargetsBranchOnRemote } from '../shared/git-remote-branch-name'
+import { findGitRemoteNameByFetchUrl } from '../shared/git-remote-url-index'
 import type { GitPushTarget } from '../shared/worktree/types'

 type RelayGit = (args: string[], cwd: string) => Promise<{ stdout: string; stderr: string }>
@@ -67,31 +68,19 @@ type ConfiguredPushRemote = {
  branchRemote: string | null
 }

+// Host-side twin of `src/main/git/remote.ts`: one `git remote -v` instead of
+// `git remote` plus a serial `git remote get-url` per remote.
 async function findRemoteNameForUrl(
  git: RelayGit,
  worktreePath: string,
  remoteUrl: string
 ): Promise<string | null> {
  try {
-    const { stdout } = await git(['remote'], worktreePath)
-    const remotes = stdout
-      .split(/\r?\n/)
-      .map((line) => line.trim())
-      .filter(Boolean)
-    for (const remoteName of remotes) {
-      try {
-        const { stdout: urlStdout } = await git(['remote', 'get-url', remoteName], worktreePath)
-        if (urlStdout.trim() === remoteUrl) {
-          return remoteName
-        }
-      } catch {
-        // Ignore a remote that disappeared or has no fetch URL.
-      }
-    }
+    const { stdout } = await git(['remote', '-v'], worktreePath)
+    return findGitRemoteNameByFetchUrl(stdout, (candidateUrl) => candidateUrl === remoteUrl)
  } catch {
    return null
  }
-  return null
 }

 async function normalizePushRemote(
@@ -120,9 +109,17 @@ async function getConfiguredPushRemote(
  if (!remote) {
    return null
  }
+  const normalizedRemote = await normalizePushRemote(git, worktreePath, remote)
+  // The two usually name the same URL; resolving it twice reads the remote table twice.
+  if (!branchRemote) {
+    return { remote: normalizedRemote, branchRemote: null }
+  }
  return {
-    remote: await normalizePushRemote(git, worktreePath, remote),
-    branchRemote: branchRemote ? await normalizePushRemote(git, worktreePath, branchRemote) : null
+    remote: normalizedRemote,
+    branchRemote:
+      branchRemote === remote
+        ? normalizedRemote
+        : await normalizePushRemote(git, worktreePath, branchRemote)
  }
 }

@@ -15,6 +15,7 @@ import {
  isUnsupportedWorktreeListZError
 } from './git-worktree-command-capabilities'
 import { gitCredentialPromptGuardEnv } from './git-credential-prompt-env'
+import { parseGitRemoteFetchUrls } from './git-remote-url-index'
 import { GIT_HISTORY_COMMIT_FORMAT, parseGitHistoryLog } from './git-history-log-parser'
 import {
  githubPullRequestHeadLocalRef,
@@ -214,6 +215,41 @@ describeBinaryCompatibility('real Git binary compatibility', () => {
    await expect(runGit(['merge-base', '--end-of-options', head, unrelated])).rejects.toBeDefined()
  })

+  // Why pin this: Orca answers "which remote has this URL" from one `git remote -v`
+  // instead of one `git remote get-url` per remote. That is only equivalent if both
+  // commands report the same URL — the insteadOf-expanded first `remote.<name>.url`,
+  // which a raw config read does not produce — on every supported Git.
+  it('reports the same fetch URL from remote -v as from remote get-url', async () => {
+    await runGit(['config', 'url.git@example.invalid:.insteadOf', 'https://example.invalid/'])
+    await runGit(['remote', 'add', 'compat-single', 'https://example.invalid/a/repo.git'])
+    await runGit(['remote', 'add', 'compat-multi', 'https://example.invalid/b/repo.git'])
+    await runGit([
+      'config',
+      '--add',
+      'remote.compat-multi.url',
+      'https://example.invalid/b2/repo.git'
+    ])
+    await runGit([
+      'config',
+      'remote.compat-multi.pushurl',
+      'https://push.example.invalid/b/repo.git'
+    ])
+    try {
+      const fetchUrls = parseGitRemoteFetchUrls((await runGit(['remote', '-v'])).stdout)
+      for (const name of ['compat-single', 'compat-multi']) {
+        const getUrl = (await runGit(['remote', 'get-url', name])).stdout.trim()
+        expect(fetchUrls.get(name)).toBe(getUrl)
+      }
+      expect(fetchUrls.get('compat-single')).toBe('git@example.invalid:a/repo.git')
+      // A `pushurl` must not displace the fetch URL the scan compares against.
+      expect(fetchUrls.get('compat-multi')).toBe('git@example.invalid:b/repo.git')
+    } finally {
+      await runGit(['remote', 'remove', 'compat-single'])
+      await runGit(['remote', 'remove', 'compat-multi'])
+      await runGit(['config', '--unset-all', 'url.git@example.invalid:.insteadOf'])
+    }
+  })
+
  it('recognizes ref and merge-tree compatibility boundaries', async () => {
    const fetchHeadPath = join(repoPath, '.git', 'FETCH_HEAD')
    await writeFile(fetchHeadPath, 'sentinel\n')
@@ -0,0 +1,175 @@
+// Why: resolving a URL-valued `branch.<name>.remote` (or `remote.pushDefault`) to a
+// remote name used to cost `git remote` plus one serial `git remote get-url` per remote.
+// `hasConfiguredBranchPushTarget` resolves up to two of them, so a 58-remote repo paid
+// up to 118 subprocesses for one question. These tests pin the count and result parity.
+
+import { describe, expect, it } from 'vitest'
+import {
+  getConfiguredBranchRemoteUpstream,
+  hasConfiguredBranchPushTarget
+} from './git-configured-branch-target'
+
+const BRANCH = 'imp/translation'
+const FORK_URL = 'https://github.com/contributor/orca.git'
+const UPSTREAM_URL = 'https://github.com/stablyai/orca.git'
+
+type RemoteRow = { name: string; fetchUrl: string; pushUrl?: string }
+
+type Fixture = {
+  remotes: readonly RemoteRow[]
+  config: Readonly<Record<string, string>>
+}
+
+function makeRunner(fixture: Fixture): {
+  runGit: (args: string[]) => Promise<{ stdout: string }>
+  spawns: string[][]
+} {
+  const spawns: string[][] = []
+  const runGit = async (args: string[]): Promise<{ stdout: string }> => {
+    spawns.push(args)
+    if (args[0] === 'config' && args[1] === '--get') {
+      const value = fixture.config[args[2]]
+      if (value === undefined) {
+        throw Object.assign(new Error('config key is not set'), { code: 1 })
+      }
+      return { stdout: `${value}\n` }
+    }
+    if (args[0] === 'remote' && args[1] === '-v') {
+      return {
+        stdout: fixture.remotes
+          .flatMap((remote) => [
+            `${remote.name}\t${remote.fetchUrl} (fetch)`,
+            `${remote.name}\t${remote.pushUrl ?? remote.fetchUrl} (push)`
+          ])
+          .join('\n')
+      }
+    }
+    if (args[0] === 'remote' && args.length === 1) {
+      return { stdout: `${fixture.remotes.map((remote) => remote.name).join('\n')}\n` }
+    }
+    if (args[0] === 'remote' && args[1] === 'get-url') {
+      const match = fixture.remotes.find((remote) => remote.name === args[2])
+      if (!match) {
+        throw new Error(`No such remote ${args[2]}`)
+      }
+      return { stdout: `${match.fetchUrl}\n` }
+    }
+    throw new Error(`unexpected git command: ${args.join(' ')}`)
+  }
+  return { runGit, spawns }
+}
+
+const fiftyEightRemotes: RemoteRow[] = [
+  { name: 'origin', fetchUrl: UPSTREAM_URL },
+  ...Array.from({ length: 56 }, (_, index) => ({
+    name: `pr-user${index}-orca`,
+    fetchUrl: `https://github.com/user${index}/orca.git`
+  })),
+  { name: 'pr-contributor-orca', fetchUrl: FORK_URL }
+]
+
+describe('hasConfiguredBranchPushTarget', () => {
+  it('resolves both URL-valued remotes from one remote table read at 58 remotes', async () => {
+    const { runGit, spawns } = makeRunner({
+      remotes: fiftyEightRemotes,
+      config: {
+        [`branch.${BRANCH}.pushRemote`]: FORK_URL,
+        [`branch.${BRANCH}.remote`]: FORK_URL,
+        [`branch.${BRANCH}.merge`]: `refs/heads/${BRANCH}`
+      }
+    })
+
+    await expect(hasConfiguredBranchPushTarget(runGit, BRANCH)).resolves.toBe(true)
+
+    // Both the push remote and the branch remote name the same URL, so one table read answers.
+    expect(spawns.filter((args) => args[0] === 'remote')).toEqual([['remote', '-v']])
+    expect(spawns.filter((args) => args[1] === 'get-url')).toEqual([])
+  })
+
+  it('keeps the not-set case false when no remote is configured', async () => {
+    const { runGit } = makeRunner({ remotes: fiftyEightRemotes, config: {} })
+    await expect(hasConfiguredBranchPushTarget(runGit, BRANCH)).resolves.toBe(false)
+  })
+
+  it('keeps the URL itself as the remote name when nothing matches', async () => {
+    const { runGit } = makeRunner({
+      remotes: [{ name: 'origin', fetchUrl: UPSTREAM_URL }],
+      config: {
+        [`branch.${BRANCH}.pushRemote`]: FORK_URL,
+        [`branch.${BRANCH}.remote`]: FORK_URL,
+        [`branch.${BRANCH}.merge`]: 'refs/heads/other'
+      }
+    })
+    // Unchanged no-match fallback: both remotes stay the raw URL, so they still agree
+    // and the differently named merge branch is still pushable.
+    await expect(hasConfiguredBranchPushTarget(runGit, BRANCH)).resolves.toBe(true)
+  })
+})
+
+describe('getConfiguredBranchRemoteUpstream', () => {
+  const remoteTrackingRefExists = async (): Promise<boolean> => true
+
+  it('picks the first remote holding a duplicated URL', async () => {
+    const { runGit, spawns } = makeRunner({
+      remotes: [
+        { name: 'origin', fetchUrl: UPSTREAM_URL },
+        { name: 'fork-a', fetchUrl: FORK_URL },
+        { name: 'fork-b', fetchUrl: FORK_URL }
+      ],
+      config: {
+        [`branch.${BRANCH}.remote`]: FORK_URL,
+        [`branch.${BRANCH}.merge`]: `refs/heads/${BRANCH}`
+      }
+    })
+
+    await expect(
+      getConfiguredBranchRemoteUpstream(runGit, BRANCH, remoteTrackingRefExists)
+    ).resolves.toEqual({
+      upstreamName: `fork-a/${BRANCH}`,
+      remoteName: 'fork-a',
+      branchName: BRANCH,
+      isConfiguredUpstream: false
+    })
+    expect(spawns.filter((args) => args[0] === 'remote')).toEqual([['remote', '-v']])
+  })
+
+  it('ignores a push URL when fetch and push differ', async () => {
+    const { runGit } = makeRunner({
+      remotes: [{ name: 'split', fetchUrl: UPSTREAM_URL, pushUrl: FORK_URL }],
+      config: {
+        [`branch.${BRANCH}.remote`]: FORK_URL,
+        [`branch.${BRANCH}.merge`]: `refs/heads/${BRANCH}`
+      }
+    })
+    await expect(
+      getConfiguredBranchRemoteUpstream(runGit, BRANCH, remoteTrackingRefExists)
+    ).resolves.toBeNull()
+  })
+
+  it('returns null with no remotes at all', async () => {
+    const { runGit } = makeRunner({
+      remotes: [],
+      config: {
+        [`branch.${BRANCH}.remote`]: FORK_URL,
+        [`branch.${BRANCH}.merge`]: `refs/heads/${BRANCH}`
+      }
+    })
+    await expect(
+      getConfiguredBranchRemoteUpstream(runGit, BRANCH, remoteTrackingRefExists)
+    ).resolves.toBeNull()
+  })
+
+  it('keeps a plain named remote untouched', async () => {
+    const { runGit, spawns } = makeRunner({
+      remotes: fiftyEightRemotes,
+      config: {
+        [`branch.${BRANCH}.remote`]: 'origin',
+        [`branch.${BRANCH}.merge`]: `refs/heads/${BRANCH}`
+      }
+    })
+    await expect(
+      getConfiguredBranchRemoteUpstream(runGit, BRANCH, remoteTrackingRefExists)
+    ).resolves.toMatchObject({ remoteName: 'origin' })
+    expect(spawns.filter((args) => args[0] === 'remote')).toEqual([])
+  })
+})
@@ -1,4 +1,5 @@
 import { gitRefTargetsBranchOnRemote } from './git-remote-branch-name'
+import { findGitRemoteNameByFetchUrl } from './git-remote-url-index'

 type GitCommandRunner = (args: string[]) => Promise<{ stdout: string }>

@@ -25,30 +26,18 @@ function isUrlValuedRemote(remote: string): boolean {
  return /^[A-Za-z][A-Za-z0-9+.-]*:\/\//.test(remote) || /^[^@/:]+@[^:]+:.+/.test(remote)
 }

+// `hasConfiguredBranchPushTarget` resolves up to two URL-valued remotes, so the old
+// per-remote `get-url` scan cost up to 2 x (1 + remotes) subprocesses per call.
 async function findRemoteNameForUrl(
  runGit: GitCommandRunner,
  remoteUrl: string
 ): Promise<string | null> {
  try {
-    const { stdout } = await runGit(['remote'])
-    const remotes = stdout
-      .split(/\r?\n/)
-      .map((line) => line.trim())
-      .filter(Boolean)
-    for (const remoteName of remotes) {
-      try {
-        const { stdout: urlStdout } = await runGit(['remote', 'get-url', remoteName])
-        if (urlStdout.trim() === remoteUrl) {
-          return remoteName
-        }
-      } catch {
-        // Ignore a remote that disappeared or has no fetch URL.
-      }
-    }
+    const { stdout } = await runGit(['remote', '-v'])
+    return findGitRemoteNameByFetchUrl(stdout, (candidateUrl) => candidateUrl === remoteUrl)
  } catch {
    return null
  }
-  return null
 }

 export async function getConfiguredBranchRemoteUpstream(
@@ -101,11 +90,14 @@ export async function hasConfiguredBranchPushTarget(
  const pushRemoteName = isUrlValuedRemote(remote)
    ? ((await findRemoteNameForUrl(runGit, remote)) ?? remote)
    : remote
-  const branchRemoteName = branchRemote
-    ? isUrlValuedRemote(branchRemote)
-      ? ((await findRemoteNameForUrl(runGit, branchRemote)) ?? branchRemote)
-      : branchRemote
-    : null
+  // The two usually name the same URL; resolving it twice reads the remote table twice.
+  const branchRemoteName = !branchRemote
+    ? null
+    : branchRemote === remote
+      ? pushRemoteName
+      : isUrlValuedRemote(branchRemote)
+        ? ((await findRemoteNameForUrl(runGit, branchRemote)) ?? branchRemote)
+        : branchRemote
  if (gitRefTargetsBranchOnRemote(baseRef, pushRemoteName, branchName)) {
    return false
  }
@@ -0,0 +1,112 @@
+import { describe, expect, it } from 'vitest'
+import {
+  findGitRemoteNameByFetchUrl,
+  parseGitRemoteFetchUrls,
+  parseGitRemoteVerboseLine
+} from './git-remote-url-index'
+
+const SSH_URL = 'git@github.com:contributor/orca.git'
+const HTTPS_URL = 'https://github.com/contributor/orca.git'
+
+function verbose(rows: readonly (readonly [string, string])[]): string {
+  return rows.map(([name, url]) => `${name}\t${url}`).join('\n')
+}
+
+describe('parseGitRemoteVerboseLine', () => {
+  it('reads the name, URL and direction', () => {
+    expect(parseGitRemoteVerboseLine(`origin\t${HTTPS_URL} (fetch)`)).toEqual({
+      name: 'origin',
+      url: HTTPS_URL,
+      direction: 'fetch'
+    })
+  })
+
+  it('keeps a URL that itself contains spaces and parentheses', () => {
+    const url = '/tmp/my repo (mirror)'
+    expect(parseGitRemoteVerboseLine(`local\t${url} (push)`)).toEqual({
+      name: 'local',
+      url,
+      direction: 'push'
+    })
+  })
+
+  it('rejects the URL-less row git prints for a pushurl-only remote', () => {
+    expect(parseGitRemoteVerboseLine('pushonly\t')).toBeNull()
+    expect(parseGitRemoteVerboseLine('not a remote row')).toBeNull()
+  })
+})
+
+describe('parseGitRemoteFetchUrls', () => {
+  it('returns nothing for a repo with no remotes', () => {
+    expect([...parseGitRemoteFetchUrls('')]).toEqual([])
+  })
+
+  it('keeps only fetch rows, in git remote order', () => {
+    const stdout = verbose([
+      ['a', `${SSH_URL} (fetch)`],
+      ['a', `${SSH_URL} (push)`],
+      ['b', `${HTTPS_URL} (fetch)`],
+      ['b', 'https://github.com/contributor/other.git (push)']
+    ])
+    expect([...parseGitRemoteFetchUrls(stdout)]).toEqual([
+      ['a', SSH_URL],
+      ['b', HTTPS_URL]
+    ])
+  })
+
+  it('parses CRLF output', () => {
+    const stdout = `a\t${SSH_URL} (fetch)\r\na\t${SSH_URL} (push)\r\n`
+    expect([...parseGitRemoteFetchUrls(stdout)]).toEqual([['a', SSH_URL]])
+  })
+
+  it('takes the first URL of a multi-URL remote, matching remote get-url', () => {
+    const stdout = verbose([
+      ['multi', `${SSH_URL} (fetch)`],
+      ['multi', `${SSH_URL} (push)`],
+      ['multi', `${HTTPS_URL} (push)`]
+    ])
+    expect(parseGitRemoteFetchUrls(stdout).get('multi')).toBe(SSH_URL)
+  })
+
+  it('scales to 58 remotes without losing order', () => {
+    const rows = Array.from({ length: 58 }, (_, index) => [
+      `r${index}`,
+      `https://example.com/o${index}/repo.git`
+    ])
+    const stdout = rows
+      .flatMap(([name, url]) => [`${name}\t${url} (fetch)`, `${name}\t${url} (push)`])
+      .join('\n')
+    const parsed = [...parseGitRemoteFetchUrls(stdout)]
+    expect(parsed).toHaveLength(58)
+    expect(parsed[0]).toEqual(['r0', 'https://example.com/o0/repo.git'])
+    expect(parsed[57]).toEqual(['r57', 'https://example.com/o57/repo.git'])
+  })
+})
+
+describe('findGitRemoteNameByFetchUrl', () => {
+  const stdout = verbose([
+    ['origin', 'https://github.com/stablyai/orca.git (fetch)'],
+    ['origin', 'https://github.com/stablyai/orca.git (push)'],
+    ['first-fork', `${SSH_URL} (fetch)`],
+    ['first-fork', `${SSH_URL} (push)`],
+    ['second-fork', `${SSH_URL} (fetch)`],
+    ['second-fork', `${SSH_URL} (push)`]
+  ])
+
+  it('returns the first remote holding a duplicated URL', () => {
+    expect(findGitRemoteNameByFetchUrl(stdout, (url) => url === SSH_URL)).toBe('first-fork')
+  })
+
+  it('returns null when nothing matches', () => {
+    expect(findGitRemoteNameByFetchUrl(stdout, (url) => url === HTTPS_URL)).toBeNull()
+  })
+
+  it('ignores push URLs when fetch and push differ', () => {
+    const split = verbose([
+      ['split', `${SSH_URL} (fetch)`],
+      ['split', `${HTTPS_URL} (push)`]
+    ])
+    expect(findGitRemoteNameByFetchUrl(split, (url) => url === SSH_URL)).toBe('split')
+    expect(findGitRemoteNameByFetchUrl(split, (url) => url === HTTPS_URL)).toBeNull()
+  })
+})
@@ -0,0 +1,64 @@
+// Why: "which remote has this URL?" was answered with one `git remote get-url`
+// subprocess per remote, awaited serially -- 58 spawns on a repo with 58 remotes,
+// on every push-target resolution. `git remote -v` answers for every remote from
+// one child.
+//
+// `remote -v` is the faithful one-command form, not `config --get-regexp '^remote\.'`:
+// both `remote -v` and `remote get-url` print the URL *after* `url.<base>.insteadOf`
+// expansion and pick the first of several `remote.<name>.url` values, while raw config
+// reads return the unexpanded value and the last of the multiple values.
+//
+// `remote -v` also predates `remote get-url` (2.7), so this lowers rather than raises
+// the Git floor and needs no capability gate.
+
+import { iterateProcessOutputLines } from './process-output-field-scanner'
+
+export type GitRemoteVerboseEntry = {
+  name: string
+  url: string
+  direction: 'fetch' | 'push'
+}
+
+// Greedy prefix so a URL containing spaces or parentheses keeps them.
+const REMOTE_VERBOSE_URL_PATTERN = /^(.*) \((fetch|push)\)$/
+
+/** Parse one `<name>\t<url> (fetch|push)` row. */
+export function parseGitRemoteVerboseLine(line: string): GitRemoteVerboseEntry | null {
+  const tabIndex = line.indexOf('\t')
+  if (tabIndex === -1) {
+    return null
+  }
+  const name = line.slice(0, tabIndex)
+  const match = REMOTE_VERBOSE_URL_PATTERN.exec(line.slice(tabIndex + 1).trim())
+  return match ? { name, url: match[1], direction: match[2] as 'fetch' | 'push' } : null
+}
+
+/**
+ * Fetch URL per remote in `git remote` order -- the value `git remote get-url <name>`
+ * prints. A remote configured with only a `pushurl` has no fetch row and is absent
+ * here; `get-url` echoed the remote's own name for it, which no caller can match.
+ */
+export function parseGitRemoteFetchUrls(stdout: string): Map<string, string> {
+  const fetchUrls = new Map<string, string>()
+  for (const line of iterateProcessOutputLines(stdout)) {
+    const parsed = parseGitRemoteVerboseLine(line)
+    // First wins: `get-url` without `--all` prints the first `remote.<name>.url`.
+    if (parsed?.direction === 'fetch' && !fetchUrls.has(parsed.name)) {
+      fetchUrls.set(parsed.name, parsed.url)
+    }
+  }
+  return fetchUrls
+}
+
+/** First remote whose fetch URL matches, in the order the per-remote scan visited them. */
+export function findGitRemoteNameByFetchUrl(
+  stdout: string,
+  matchesUrl: (url: string) => boolean
+): string | null {
+  for (const [name, url] of parseGitRemoteFetchUrls(stdout)) {
+    if (matchesUrl(url)) {
+      return name
+    }
+  }
+  return null
+}