flow next: find a PR pushed under a different public branch name

plugins/flow/bin/lib/router.js

@@ -338,16 +338,27 @@ function passCommand(root) {
 
 // prNumber(root, branch) -> "41" | null. gh is optional: no gh, no network,
 // or any failure all mean "no PR", which routes to 11 (open one) not 12.
+// Stealth pushes HEAD:<plain-name>, often from a fork, so `pr view <local>`
+// misses; fall back to a head-name lookup under the branch's upstream name.
 function prNumber(root, branch) {
   if (!branch || branch === 'HEAD') return null;
-  const r = spawnSync('gh', ['pr', 'view', branch, '--json', 'number', '-q', '.number'], {
-    cwd: root,
-    encoding: 'utf8',
-    timeout: 15000,
-  });
-  if (r.status !== 0) return null;
-  const n = (r.stdout || '').trim();
-  return /^\d+$/.test(n) ? n : null;
+  const ghNumber = (args) => {
+    const r = spawnSync('gh', args, { cwd: root, encoding: 'utf8', timeout: 15000 });
+    if (r.status !== 0) return null;
+    const n = (r.stdout || '').trim();
+    return /^\d+$/.test(n) ? n : null;
+  };
+  const direct = ghNumber(['pr', 'view', branch, '--json', 'number', '-q', '.number']);
+  if (direct) return direct;
+  const merge = git(root, ['config', `branch.${branch}.merge`]).out;
+  const name = merge.replace(/^refs\/heads\//, '');
+  if (!name || name === merge || name === branch) return null;
+  const remote = git(root, ['config', `branch.${branch}.remote`]).out;
+  const url = remote ? git(root, ['config', `remote.${remote}.url`]).out : '';
+  const m = url.match(/^(?:[\w.-]+@[^:/]+:|[a-z+]+:\/\/(?:[^@/]+@)?[^/]+\/)([A-Za-z0-9-]+)\/[^/]+?(?:\.git)?\/?$/i);
+  if (!m) return null;
+  return ghNumber(['pr', 'list', '--head', name, '--state', 'all', '--json', 'number,headRepositoryOwner',
+    '-q', `[.[] | select(.headRepositoryOwner.login == "${m[1]}")][0].number`]);
 }
 
 // ─────────────────────────────────────────────────────────────────────────────

plugins/flow/scripts/tests/test_next.sh

@@ -584,6 +584,40 @@ Verified: 2026-09-08 by user" \
 	rm -rf "$home" "$proj"
 }
 
+t_next_row12_pr_found_by_upstream_name() {
+	# stealth pushes HEAD:<plain-name>, so `gh pr view <local-branch>` finds
+	# nothing; the PR is only findable by the upstream branch name
+	local home proj base sha
+	home=$(tmp_dir)
+	proj=$(tmp_repo)
+	base=$(git -C "$proj" rev-parse --short HEAD)
+	nx_feature "$proj" 001-x
+	sha=$(nx_commit "$proj" a.py)
+	nx_tasks "$proj/.specs/001-x/TASKS.md" "$base" "Approved: 2026-09-08 by user
+Verified: 2026-09-08 by user" \
+		"- [x] T001 a — files: a.py — verify: \`true\` — done: $sha" \
+		'' '## Gates' "- [x] G001 clean — verify: \`true\` — done: $sha"
+	printf 'gates green\n' >"$proj/.specs/001-x/PASS-$sha.md"
+	git -C "$proj" checkout -qb flow/x
+	printf '#!/bin/sh\ncase "$*" in\n"pr list --head feat/x "*someone*) echo 77 ;;\n*) exit 1 ;;\nesac\n' >"$home/gh"
+	chmod +x "$home/gh"
+	run_cmd bash -c 'cd "$1" || exit 1; export HOME="$2"; export PATH="$2:$PATH"; shift 2; exec "$@"' \
+		_ "$proj" "$home" node "$NX_CLI_PATH" next --json
+	assert_contains "$OUT" '"state": "shippable"' "no upstream configured: the old no-PR answer holds"
+	git -C "$proj" config branch.flow/x.remote fork
+	git -C "$proj" config branch.flow/x.merge refs/heads/feat/x
+	git -C "$proj" config remote.fork.url /somewhere/local/path
+	run_cmd bash -c 'cd "$1" || exit 1; export HOME="$2"; export PATH="$2:$PATH"; shift 2; exec "$@"' \
+		_ "$proj" "$home" node "$NX_CLI_PATH" next --json
+	assert_contains "$OUT" '"state": "shippable"' "a remote url with no parseable owner is not guessed at"
+	git -C "$proj" config remote.fork.url git@github.com:someone/repo.git
+	run_cmd bash -c 'cd "$1" || exit 1; export HOME="$2"; export PATH="$2:$PATH"; shift 2; exec "$@"' \
+		_ "$proj" "$home" node "$NX_CLI_PATH" next --json
+	assert_contains "$OUT" '"state": "shipped"' "a PR under the upstream branch name is found"
+	assert_contains "$OUT" 'PR #77' "and its number is reported"
+	rm -rf "$home" "$proj"
+}
+
 t_next_row13_idle() {
 	local home proj
 	home=$(tmp_dir)