Add create_pull_request_on_conflict option to automerge tasks (#3632)

Co-authored-by: Ben French <[email protected]>

AUTHORS.rst

@@ -36,3 +36,4 @@ For example:
 
 * Ed Rivas (jerivas)
 * Gustavo Tandeciarz (dcinzona)
+* Ben French (BenjaminFrench)

cumulusci/tasks/github/merge.py

@@ -34,6 +34,9 @@ class MergeBranch(BaseGithubTask):
         "update_future_releases": {
             "description": "If true, then include release branches that are not the lowest release number even if they are not child branches. Defaults to False."
         },
+        "create_pull_request_on_conflict": {
+            "description": "If true, then create a pull request when a merge conflict arises. Defaults to True."
+        },
     }
 
     def _init_options(self, kwargs):
@@ -58,6 +61,12 @@ def _init_options(self, kwargs):
         self.options["update_future_releases"] = process_bool_arg(
             self.options.get("update_future_releases") or False
         )
+        if "create_pull_request_on_conflict" not in self.options:
+            self.options["create_pull_request_on_conflict"] = True
+        else:
+            self.options["create_pull_request_on_conflict"] = process_bool_arg(
+                self.options.get("create_pull_request_on_conflict")
+            )
 
     def _init_task(self):
         super()._init_task()
@@ -245,30 +254,39 @@ def _merge(self, branch_name, source, commit):
             if e.code != http.client.CONFLICT:
                 raise
 
-            if branch_name in self._get_existing_prs(
-                self.options["source_branch"], self.options["branch_prefix"]
-            ):
-                self.logger.info(
-                    f"Merge conflict on branch {branch_name}: merge PR already exists"
-                )
-                return
-
-            try:
-                pull = self.repo.create_pull(
-                    title=f"Merge {source} into {branch_name}",
-                    base=branch_name,
-                    head=source,
-                    body="This pull request was automatically generated because "
-                    "an automated merge hit a merge conflict",
-                )
+            if self.options["create_pull_request_on_conflict"]:
+                self._create_conflict_pull_request(branch_name, source)
+            else:
                 self.logger.info(
-                    f"Merge conflict on branch {branch_name}: created pull request #{pull.number}"
-                )
-            except github3.exceptions.UnprocessableEntity as e:
-                self.logger.error(
-                    f"Error creating merge conflict pull request to merge {source} into {branch_name}:\n{e.response.text}"
+                    f"Merge conflict on branch {branch_name}: skipping pull request creation"
                 )
 
+    def _create_conflict_pull_request(self, branch_name, source):
+        """Attempt to create a pull request from source into branch_name if merge operation encounters a conflict"""
+        if branch_name in self._get_existing_prs(
+            self.options["source_branch"], self.options["branch_prefix"]
+        ):
+            self.logger.info(
+                f"Merge conflict on branch {branch_name}: merge PR already exists"
+            )
+            return
+
+        try:
+            pull = self.repo.create_pull(
+                title=f"Merge {source} into {branch_name}",
+                base=branch_name,
+                head=source,
+                body="This pull request was automatically generated because "
+                "an automated merge hit a merge conflict",
+            )
+            self.logger.info(
+                f"Merge conflict on branch {branch_name}: created pull request #{pull.number}"
+            )
+        except github3.exceptions.UnprocessableEntity as e:
+            self.logger.error(
+                f"Error creating merge conflict pull request to merge {source} into {branch_name}:\n{e.response.text}"
+            )
+
     def _is_source_branch_direct_descendent(self, branch_name):
         """Returns True if branch is a direct descendent of the source branch"""
         source_dunder_count = self.options["source_branch"].count("__")

cumulusci/tasks/github/tests/test_merge.py

@@ -278,6 +278,45 @@ def test_task_output__feature_branch_merge_conflict(self):
             assert expected_log == actual_log
         assert 7 == len(responses.calls)
 
+    @responses.activate
+    def test_task_output__feature_branch_merge_conflict_skip_pull_requests(self):
+        self._mock_repo()
+        self._mock_branch(self.branch)
+        self.mock_pulls()
+        branch_name = "feature/a-test"
+        branches = []
+        branches.append(self._get_expected_branch("main"))
+        branches.append(self._get_expected_branch(branch_name))
+        branches = self._mock_branches(branches)
+        self._mock_compare(
+            base=branches[1]["name"],
+            head=self.project_config.repo_commit,
+            files=[{"filename": "test.txt"}],
+        )
+        self._mock_merge(http.client.CONFLICT)
+        self._mock_pull_create(1, 2)
+        with LogCapture() as log:
+            task = self._create_task(
+                task_config={
+                    "options": {
+                        "create_pull_request_on_conflict": "False",
+                    }
+                }
+            )
+            task()
+            actual_log = self._get_log_lines(log)
+
+            expected_log = log_header() + [
+                ("DEBUG", "Skipping branch main: is source branch"),
+                ("DEBUG", "Found descendents of main to update: ['feature/a-test']"),
+                (
+                    "INFO",
+                    "Merge conflict on branch feature/a-test: skipping pull request creation",
+                ),
+            ]
+            assert expected_log == actual_log
+        assert 5 == len(responses.calls)
+
     @responses.activate
     def test_merge__error_on_merge_conflict_pr(self):
         self._mock_repo()
@@ -402,6 +441,59 @@ def test_task_output__main_parent_with_child_pr(self):
         assert expected_log == actual_log
         assert 7 == len(responses.calls)
 
+    @responses.activate
+    def test_task_output__main_parent_with_child_skip_pull_requests(self):
+        self._mock_repo()
+        self._mock_branch(self.branch)
+        # branches
+        parent_branch_name = "feature/a-test"
+        child_branch_name = "feature/a-test__a-child"
+        branches = []
+        branches.append(self._get_expected_branch("main"))
+        branches.append(self._get_expected_branch(parent_branch_name))
+        branches.append(self._get_expected_branch(child_branch_name))
+        branches = self._mock_branches(branches)
+        # pull request
+        pull = self._get_expected_pull_request(1, 2)
+        pull["base"]["ref"] = parent_branch_name
+        pull["base"]["sha"] = branches[1]["commit"]["sha"]
+        pull["head"]["ref"] = child_branch_name
+        self.mock_pulls(pulls=[pull])
+        # compare
+        self._mock_compare(
+            base=parent_branch_name,
+            head=self.project_config.repo_commit,
+            files=[{"filename": "test.txt"}],
+        )
+        # merge
+        self._mock_merge(http.client.CONFLICT)
+        # create PR
+        self._mock_pull_create(1, 2)
+        with LogCapture() as log:
+            task = self._create_task(
+                task_config={
+                    "options": {
+                        "create_pull_request_on_conflict": "False",
+                    }
+                }
+            )
+            task()
+            actual_log = self._get_log_lines(log)
+        expected_log = log_header() + [
+            ("DEBUG", "Skipping branch main: is source branch"),
+            (
+                "DEBUG",
+                "Skipping branch feature/a-test__a-child: is not a direct descendent of main",
+            ),
+            ("DEBUG", "Found descendents of main to update: ['feature/a-test']"),
+            (
+                "INFO",
+                "Merge conflict on branch feature/a-test: skipping pull request creation",
+            ),
+        ]
+        assert expected_log == actual_log
+        assert 5 == len(responses.calls)
+
     @responses.activate
     def test_task_output__main_merge_to_feature(self):
         """Tests that commits to the main branch are merged to the expected feature branches"""