fix(upstream): preserve selected refs in companion commands (#591)

* fix(upstream): preserve selected refs in companion commands

* fix(upstream): quote companion command arguments

* docs(changelog): record fix for #591

tests/test_upstream_crossrefs.py

@@ -0,0 +1,67 @@
+"""Companion commands must inspect the same selected upstream ref."""
+import re
+import shlex
+import shutil
+import subprocess
+import sys
+import unittest
+from pathlib import Path
+
+from tests.test_check_upstream_updates import UpstreamCheckerRepoFixture, FRONTMATTER
+
+
+class CompanionRefTests(UpstreamCheckerRepoFixture):
+    branch_name = "release/next"
+
+    def setUp(self):
+        super().setUp()
+        source = Path(__file__).resolve().parent.parent
+        shutil.copy(source / "tools/upstream_triage.py", self.root / "tools/upstream_triage.py")
+        self.remote = "forks/template"
+        self.branch = self.branch_name
+        # A local remote permits the real companion CLI's normal fetch without
+        # contacting a service. The selected branch differs from master.
+        self.add_remote(self.remote, str(self.root))
+        self.git("update-ref", f"refs/remotes/{self.remote}/master", "HEAD")
+        agents = self.root / "AGENTS.md"
+        agents.write_text(FRONTMATTER.replace("1.0.0", "2.0.0"), encoding="utf-8")
+        self.git("add", "AGENTS.md")
+        self.git("commit", "-qm", "update next-release methodology")
+        self.git("branch", self.branch)
+        self.git("update-ref", f"refs/remotes/{self.remote}/{self.branch}", "HEAD")
+        self.git("reset", "--hard", "HEAD~1")
+
+    def git(self, *args):
+        return subprocess.run(["git", *args], cwd=self.root, check=True, capture_output=True)
+
+    def follow(self, command):
+        argv = shlex.split(command)
+        argv[0] = sys.executable
+        result = subprocess.run(argv, cwd=self.root, capture_output=True, text=True, encoding="utf-8")
+        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+        return result.stdout
+
+    def test_version_checker_companion_uses_selected_remote_and_branch(self):
+        result = self.run_checker("--remote", self.remote, "--branch", self.branch)
+        self.assertEqual(result.returncode, 0, result.stderr)
+        self.assertIn("[UPDATE]", result.stdout)
+        command = result.stdout.split("run: ", 1)[1].strip()
+        companion = self.follow(command)
+        self.assertIn(f"{self.remote}/{self.branch}", companion)
+        self.assertIn("**1** worth reviewing", companion)
+
+    def test_triage_companion_uses_selected_remote_and_branch(self):
+        result = subprocess.run(
+            [sys.executable, "tools/upstream_triage.py", "--remote", self.remote, "--branch", self.branch],
+            cwd=self.root, capture_output=True, text=True, encoding="utf-8",
+        )
+        self.assertEqual(result.returncode, 0, result.stderr)
+        self.assertIn("**1** worth reviewing", result.stdout)
+        command = re.search(r"run `(python tools/check_upstream_updates.py [^`]+)`", result.stdout).group(1)
+        companion = self.follow(command)
+        self.assertIn(f"{self.remote}/{self.branch}", companion)
+        self.assertIn("[UPDATE]", companion)
+
+
+class QuotedCompanionRefTests(CompanionRefTests):
+    branch_name = "release'next"