chore(release): reuse existing PRs and avoid early exit in prep tool

tests/tools/private/release/release_test.py

@@ -35,6 +35,7 @@ def _mock_git_and_gh(test_case):
     mock_git.branch_exists.return_value = False
     mock_git.tag_exists.return_value = False
     mock_gh.get_release_tracking_issue.side_effect = NoTrackingIssueError("Not found")
+    mock_gh.get_open_pr.return_value = None
 
 
 class TempDirTestCase(unittest.TestCase):
@@ -799,6 +800,100 @@ def test_prepare_dry_run(self, mock_replace, mock_changelog):
         self.mock_gh.get_release_tracking_issue.assert_called_once_with("2.0.0")
         self.mock_git.add_modified_and_deleted.assert_not_called()
 
+    @patch("tools.private.release.prepare.changelog_news")
+    @patch("tools.private.release.prepare.replace_version_next")
+    def test_prepare_use_associated_pr_from_tracking_issue(
+        self, mock_replace, mock_changelog
+    ):
+        # Arrange
+        args = MagicMock(version="2.0.0", issue=None, dry_run=False)
+        self.mock_git.status.side_effect = ["", ""]
+        self.mock_git.branch_exists.return_value = True
+        self.mock_gh.get_release_tracking_issue.side_effect = None
+        self.mock_gh.get_release_tracking_issue.return_value = 123
+        self.mock_gh.get_open_pr.return_value = None
+        # PR #456 is already associated in the tracking issue
+        self.mock_gh.get_issue_body.return_value = (
+            "- [ ] Prepare Release | status=pending pr=#456"
+        )
+
+        # Act
+        result = releaser.cmd_prepare(args)
+
+        # Assert
+        self.assertEqual(result, 0)
+        self.mock_git.checkout.assert_called_once_with("prepare-2.0.0")
+        self.mock_git.commit.assert_not_called()
+        self.mock_git.push.assert_called_once_with(
+            "origin", "prepare-2.0.0", set_upstream=True
+        )
+        self.mock_gh.get_open_pr.assert_called_once_with("prepare-2.0.0")
+        self.mock_gh.create_pr.assert_not_called()  # Should NOT create a new PR
+        self.mock_gh.update_issue_body.assert_called_once()
+        call_args = self.mock_gh.update_issue_body.call_args[0]
+        self.assertIn("pr=#456", call_args[1])
+
+    @patch("tools.private.release.prepare.changelog_news")
+    @patch("tools.private.release.prepare.replace_version_next")
+    def test_prepare_create_pr_when_none_associated(self, mock_replace, mock_changelog):
+        # Arrange
+        args = MagicMock(version="2.0.0", issue=None, dry_run=False)
+        self.mock_git.status.side_effect = ["", ""]
+        self.mock_git.branch_exists.return_value = True
+        self.mock_gh.get_release_tracking_issue.side_effect = None
+        self.mock_gh.get_release_tracking_issue.return_value = 123
+        self.mock_gh.get_open_pr.return_value = None
+        # No PR associated in the tracking issue
+        self.mock_gh.get_issue_body.return_value = "- [ ] Prepare Release"
+        self.mock_gh.create_pr.return_value = "https://github.com/foo/bar/pull/789"
+
+        # Act
+        result = releaser.cmd_prepare(args)
+
+        # Assert
+        self.assertEqual(result, 0)
+        self.mock_git.checkout.assert_called_once_with("prepare-2.0.0")
+        self.mock_git.commit.assert_not_called()
+        self.mock_git.push.assert_called_once_with(
+            "origin", "prepare-2.0.0", set_upstream=True
+        )
+        self.mock_gh.get_open_pr.assert_called_once_with("prepare-2.0.0")
+        self.mock_gh.create_pr.assert_called_once_with("2.0.0", 123)
+        self.mock_gh.update_issue_body.assert_called_once()
+        call_args = self.mock_gh.update_issue_body.call_args[0]
+        self.assertIn("pr=#789", call_args[1])
+
+    @patch("tools.private.release.prepare.changelog_news")
+    @patch("tools.private.release.prepare.replace_version_next")
+    def test_prepare_reuse_existing_pr(self, mock_replace, mock_changelog):
+        # Arrange
+        args = MagicMock(version="2.0.0", issue=None, dry_run=False)
+        self.mock_git.status.side_effect = ["", ""]
+        self.mock_git.branch_exists.return_value = True
+        self.mock_gh.get_release_tracking_issue.side_effect = None
+        self.mock_gh.get_release_tracking_issue.return_value = 123
+        self.mock_gh.get_open_pr.return_value = {
+            "number": 456,
+            "url": "https://github.com/foo/bar/pull/456",
+        }
+        self.mock_gh.get_issue_body.return_value = "- [ ] Prepare Release"
+
+        # Act
+        result = releaser.cmd_prepare(args)
+
+        # Assert
+        self.assertEqual(result, 0)
+        self.mock_git.checkout.assert_called_once_with("prepare-2.0.0")
+        self.mock_git.commit.assert_not_called()
+        self.mock_git.push.assert_called_once_with(
+            "origin", "prepare-2.0.0", set_upstream=True
+        )
+        self.mock_gh.get_open_pr.assert_called_once_with("prepare-2.0.0")
+        self.mock_gh.create_pr.assert_not_called()
+        self.mock_gh.update_issue_body.assert_called_once()
+        call_args = self.mock_gh.update_issue_body.call_args[0]
+        self.assertIn("pr=#456", call_args[1])
+
     @patch("tools.private.release.prepare.changelog_news")
     @patch("tools.private.release.prepare.replace_version_next")
     def test_prepare_dry_run_no_issue(self, mock_replace, mock_changelog):

tools/private/release/gh.py

@@ -162,6 +162,22 @@ def create_pr(version, issue_num):
     )
 
 
+def get_open_pr(branch_name):
+    """Returns PR info if an open PR exists for the given branch, else None."""
+    cmd = [
+        "gh",
+        "pr",
+        "list",
+        f"--repo={_REPO}",
+        f"--head={branch_name}",
+        "--state=open",
+        "--json=number,url",
+    ]
+    output = run_cmd(*cmd)
+    prs = json.loads(output) if output else []
+    return prs[0] if prs else None
+
+
 def get_pr_info(pr_num):
     """Gets information about a PR, including state, merge commit, and body."""
     output = run_cmd(

tools/private/release/prepare.py

@@ -2,7 +2,10 @@
 import pathlib
 
 from tools.private.release import changelog_news, gh, git
-from tools.private.release.release_issue import update_task_in_body
+from tools.private.release.release_issue import (
+    parse_checklist_state,
+    update_task_in_body,
+)
 from tools.private.release.utils import (
     determine_next_version,
     replace_version_next,
@@ -102,26 +105,47 @@ def cmd_prepare(args):
         print(f"[DRY RUN] Would push branch {branch_name} to origin")
     else:
         modified_files = git.status()
-        if not modified_files:
+        if modified_files:
+            # Stage all modified and deleted tracked files
+            git.add_modified_and_deleted()
+            git.commit(f"Prepare release {version}")
+        else:
             print("No files modified by the release tool. Nothing to commit.")
-            return 0
-
-        # Stage all modified and deleted tracked files
-        git.add_modified_and_deleted()
 
-        git.commit(f"Prepare release {version}")
+        print(f"Pushing branch {branch_name} to origin...")
         git.push("origin", branch_name, set_upstream=True)
 
     # --- Create PR ---
-    if args.dry_run:
-        target_issue = f"#{issue_num}" if issue_num else "<NEW_ISSUE>"
+    # Determine if we need to create a PR or reuse an existing one
+    open_pr = gh.get_open_pr(branch_name)
+    associated_pr = None
+
+    if not open_pr and issue_num:
+        body = gh.get_issue_body(issue_num)
+        state = parse_checklist_state(body)
+        associated_pr = state["prepare_release"]["pr"]
+
+    if open_pr:
+        pr_num = open_pr["number"]
+        pr_url = open_pr["url"]
+        print(f"Open Pull Request already exists: {pr_url} (PR #{pr_num})")
+    elif associated_pr:
+        pr_num = associated_pr.lstrip("#")
+        pr_url = f"https://github.com/bazel-contrib/rules_python/pull/{pr_num}"
         print(
-            f"[DRY RUN] Would create Pull Request for branch {branch_name} targeting issue {target_issue}"
+            f"PR #{pr_num} is already associated in tracking issue #{issue_num}. Using it."
         )
     else:
-        pr_url = gh.create_pr(version, issue_num)
-        pr_num = pr_url.split("/")[-1]
-        print(f"Created Pull Request: {pr_url} (PR #{pr_num})")
+        if args.dry_run:
+            target_issue = f"#{issue_num}" if issue_num else "<NEW_ISSUE>"
+            print(
+                f"[DRY RUN] Would create Pull Request for branch {branch_name} targeting issue {target_issue}"
+            )
+            pr_num = "<NEW_PR>"
+        else:
+            pr_url = gh.create_pr(version, issue_num)
+            pr_num = pr_url.split("/")[-1]
+            print(f"Created Pull Request: {pr_url} (PR #{pr_num})")
 
     # --- Update checklist ---
     if args.dry_run:

tools/private/release/release.py

@@ -10,6 +10,7 @@
 from tools.private.release import changelog_news, gh, git
 from tools.private.release.prepare import cmd_prepare
 from tools.private.release.release_issue import (
+    parse_checklist_state,
     parse_metadata_line,
     update_task_in_body,
 )
@@ -35,72 +36,6 @@ def _semver_type(value):
 # ==============================================================================
 
 
-def parse_checklist_state(body):
-    """Parses the main checklist tasks and their metadata."""
-    state = {
-        "prepare_release": {
-            "checked": False,
-            "status": None,
-            "pr": None,
-            "commit": None,
-        },
-        "create_branch": {
-            "checked": False,
-            "status": None,
-            "branch": None,
-            "commit": None,
-        },
-        "tag_final": {"checked": False, "status": None, "tag": None, "commit": None},
-        "rc_tags": {},  # Dynamically mapped: int -> metadata dict
-    }
-
-    lines = body.splitlines()
-    for line in lines:
-        parsed = parse_metadata_line(line)
-        if not parsed:
-            continue
-
-        name = parsed["name"].strip()
-        meta = parsed["metadata"]
-        checked = parsed["checked"]
-        name_lower = name.lower()
-
-        if "prepare release" in name_lower:
-            state["prepare_release"] = {
-                "checked": checked,
-                "status": meta.get("status"),
-                "pr": meta.get("pr"),
-                "commit": meta.get("commit"),
-            }
-        elif "create release branch" in name_lower:
-            state["create_branch"] = {
-                "checked": checked,
-                "status": meta.get("status"),
-                "branch": meta.get("branch"),
-                "commit": meta.get("commit"),
-            }
-        elif "tag final" in name_lower:
-            state["tag_final"] = {
-                "checked": checked,
-                "status": meta.get("status"),
-                "tag": meta.get("tag"),
-                "commit": meta.get("commit"),
-            }
-        else:
-            # Match Tag RC<num>
-            rc_match = re.match(r"Tag RC(\d+)", name, re.IGNORECASE)
-            if rc_match:
-                rc_num = int(rc_match.group(1))
-                state["rc_tags"][rc_num] = {
-                    "checked": checked,
-                    "status": meta.get("status"),
-                    "tag": meta.get("tag"),
-                    "commit": meta.get("commit"),
-                }
-
-    return state
-
-
 def parse_backports(body):
     """Parses the ## Backports checklist section."""
     body = body.replace("\r\n", "\n")

tools/private/release/release_issue.py

@@ -60,3 +60,69 @@ def update_task_in_body(body, task_name, checked, metadata):
         )
 
     return "\n".join(updated_lines)
+
+
+def parse_checklist_state(body):
+    """Parses the main checklist tasks and their metadata."""
+    state = {
+        "prepare_release": {
+            "checked": False,
+            "status": None,
+            "pr": None,
+            "commit": None,
+        },
+        "create_branch": {
+            "checked": False,
+            "status": None,
+            "branch": None,
+            "commit": None,
+        },
+        "tag_final": {"checked": False, "status": None, "tag": None, "commit": None},
+        "rc_tags": {},  # Dynamically mapped: int -> metadata dict
+    }
+
+    lines = body.splitlines()
+    for line in lines:
+        parsed = parse_metadata_line(line)
+        if not parsed:
+            continue
+
+        name = parsed["name"].strip()
+        meta = parsed["metadata"]
+        checked = parsed["checked"]
+        name_lower = name.lower()
+
+        if "prepare release" in name_lower:
+            state["prepare_release"] = {
+                "checked": checked,
+                "status": meta.get("status"),
+                "pr": meta.get("pr"),
+                "commit": meta.get("commit"),
+            }
+        elif "create release branch" in name_lower:
+            state["create_branch"] = {
+                "checked": checked,
+                "status": meta.get("status"),
+                "branch": meta.get("branch"),
+                "commit": meta.get("commit"),
+            }
+        elif "tag final" in name_lower:
+            state["tag_final"] = {
+                "checked": checked,
+                "status": meta.get("status"),
+                "tag": meta.get("tag"),
+                "commit": meta.get("commit"),
+            }
+        else:
+            # Match Tag RC<num>
+            rc_match = re.match(r"Tag RC(\d+)", name, re.IGNORECASE)
+            if rc_match:
+                rc_num = int(rc_match.group(1))
+                state["rc_tags"][rc_num] = {
+                    "checked": checked,
+                    "status": meta.get("status"),
+                    "tag": meta.get("tag"),
+                    "commit": meta.get("commit"),
+                }
+
+    return state