ci_scripts/check_versions.py: gracefully handle existence of upgrade PRs

The workflow currently fails every night because of a backlog of version
upgrade PRs already being open from previous runs. Improve
check_versions.py script so that if it can't open these PRs for versions
RISE doesn't yet build, then it finishes gracefully. Do this by trying
to confirm the existence of a PR for the given version(s), then warning
the maintainer that they should check for them manually if they can't be
detected automatically.

AI-Generated: Uses Claude Sonnet 5

Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>

Author: threexc

ci_scripts/check_versions.py

@@ -160,8 +160,36 @@ def extract_pr_url(stdout: str) -> Optional[str]:
     return None
 
 
+def find_open_pr_for_branch(branch: str) -> Optional[str]:
+    """Return the URL of an open PR with the given head branch, if any."""
+    try:
+        result = subprocess.run([
+            "gh", "pr", "list",
+            "--repo", REPO,
+            "--head", branch,
+            "--state", "open",
+            "--json", "url",
+            "--jq", ".[0].url",
+        ], capture_output=True, text=True, timeout=30)
+
+        if result.returncode != 0:
+            return None
+
+        return result.stdout.strip() or None
+
+    except (subprocess.TimeoutExpired, subprocess.SubprocessError):
+        return None
+
+
 def create_deprecation_pr(package: str, reason: str) -> Optional[str]:
     """Create a pull request to deprecate a package."""
+    branch = f"github-actions/deprecate-{package}"
+
+    existing_pr = find_open_pr_for_branch(branch)
+    if existing_pr:
+        print(f"    [=] PR already open for {package}: {existing_pr}")
+        return existing_pr
+
     try:
         git_run("fetch", "origin")
         git_run("switch", "main")
@@ -185,8 +213,6 @@ def create_deprecation_pr(package: str, reason: str) -> Optional[str]:
         else:
             print(f"    [!] No upstream issue found for {package}")
 
-        branch = f"github-actions/deprecate-{package}"
-
         configure_git_identity()
         git_run("switch", "-c", branch)
 
@@ -238,7 +264,13 @@ def create_deprecation_pr(package: str, reason: str) -> Optional[str]:
         return extract_pr_url(result.stdout) or f"PR created for {package} (URL not found in output)"
 
     except subprocess.CalledProcessError as e:
+        existing_pr = find_open_pr_for_branch(branch)
+        if existing_pr:
+            print(f"    [=] PR already open for {package}: {existing_pr}")
+            return existing_pr
         print(f"    [X] Error creating PR for {package}: {e.stderr or e}")
+        print(f"    [?] Could not confirm whether a PR already exists for {package} "
+              "— please check open PRs manually")
         return None
     except Exception as e:
         print(f"    [X] Unexpected error creating PR for {package}: {e}")
@@ -361,14 +393,19 @@ def create_upgrade_pr(package: str, package_info: Dict, new_versions: List[str])
         return None
 
     latest_version = new_versions[-1]
+    branch = f"github-actions/upgrade-{package}-{latest_version}"
+
+    existing_pr = find_open_pr_for_branch(branch)
+    if existing_pr:
+        print(f"    [=] PR already open for {package}: {existing_pr}")
+        return existing_pr
 
     try:
         configure_git_identity()
 
         git_run("fetch", "origin")
         git_run("switch", "main")
 
-        branch = f"github-actions/upgrade-{package}-{latest_version}"
         git_run("switch", "-c", branch)
 
         pypi_package_url = get_pypi_package_url(package_info)
@@ -467,7 +504,13 @@ def create_upgrade_pr(package: str, package_info: Dict, new_versions: List[str])
         return pr_url
 
     except subprocess.CalledProcessError as e:
+        existing_pr = find_open_pr_for_branch(branch)
+        if existing_pr:
+            print(f"    [=] PR already open for {package}: {existing_pr}")
+            return existing_pr
         print(f"    [X] Error creating upgrade PR for {package}: {e.stderr or e}")
+        print(f"    [?] Could not confirm whether a PR already exists for {package} "
+              "— please check open PRs manually")
         return None
     except Exception as e:
         print(f"    [X] Unexpected error creating upgrade PR for {package}: {e}")
@@ -651,9 +694,11 @@ def main():
             if r["status"] in ("need_upgrade", "can_deprecate") and r.get("pr_url") is None
         ]
         if pr_failures:
-            print(f"\n[X] PR creation failed for {len(pr_failures)} package(s): "
+            print(f"\n[?] Could not create (or confirm an existing) PR for "
+                  f"{len(pr_failures)} package(s): "
                   + ", ".join(r["package"] for r in pr_failures))
-            sys.exit(1)
+            print("    Please review open PRs to check whether one already exists "
+                  "for these packages.")
 
 
 if __name__ == "__main__":