Merge labels

README.md

@@ -118,6 +118,8 @@ You can make the following changes to labels for your repo:
 labels file 🗑
 - You can **edit** a label by changing the value for one or more parameters for
 that label 🎨
+- You can **merge** one label to another by setting the ``name`` of a label to
+that of an existing label. The merged label will be deleted.
 - You can **create** a new label by adding a new section with your desired
 parameters 📝
 
@@ -137,15 +139,18 @@ labels sync -n -o hackebrot -r pytest-emoji
 ```
 
 ```text
-This would delete the following labels:
-  - dependencies
+This would merge the following labels:
+  - dependencies to dependency
 This would update the following labels:
   - bug
   - good first issue
+This would delete the following labels:
+  - dependencies
 This would create the following labels:
   - duplicate
 This would NOT modify the following labels:
   - code quality
+  - dependency
   - docs
 ```
 

src/labels/cli.py

@@ -164,8 +164,9 @@ def sync_cmd(
     On success this will also update the local labels file, so that section
     names match the `name` parameter.
     """
-    labels_to_delete = {}
+    labels_to_merge = {}
     labels_to_update = {}
+    labels_to_delete = {}
     labels_to_create = {}
     labels_to_ignore = {}
 
@@ -187,7 +188,12 @@ def sync_cmd(
             if local_label.params_dict == remote_label.params_dict:
                 labels_to_ignore[remote_name] = local_label
             else:
-                labels_to_update[remote_name] = local_label
+                if ((remote_name != local_label.name)
+                        and (local_label.name in remote_labels)):
+                    # There is already a label with this name
+                    labels_to_merge[remote_name] = local_label.name
+                else:
+                    labels_to_update[remote_name] = local_label
         else:
             if remote_name == local_label.name:
                 labels_to_create[local_label.name] = local_label
@@ -198,7 +204,7 @@ def sync_cmd(
                     f'parameter: "{local_label.name}"',
                     err=True,
                 )
-                sys.exit(1)
+                labels_to_ignore[remote_name] = local_label
 
     for remote_name, remote_label in remote_labels.items():
         if remote_name in labels_to_update:
@@ -212,18 +218,25 @@ def sync_cmd(
     if dryrun:
         # Do not modify remote labels, but only print info
         dryrun_echo(
-            labels_to_delete, labels_to_update, labels_to_create, labels_to_ignore
+            labels_to_merge,
+            labels_to_update,
+            labels_to_delete,
+            labels_to_create,
+            labels_to_ignore
         )
-        sys.exit(0)
+        # sys.exit(0)
+        return
 
     failures = []
 
-    for name in labels_to_delete.keys():
+    # Merge has to occur before update and delete
+    for old_label, new_label in labels_to_merge.items():
         try:
-            context.client.delete_label(repository, name=name)
+            context.client.merge_label(
+                    repository, old_label=old_label, new_label=new_label)
         except LabelsException as exc:
             click.echo(str(exc), err=True)
-            failures.append(name)
+            failures.append(old_label)
 
     for name, label in labels_to_update.items():
         try:
@@ -232,6 +245,13 @@ def sync_cmd(
             click.echo(str(exc), err=True)
             failures.append(name)
 
+    for name in labels_to_delete.keys():
+        try:
+            context.client.delete_label(repository, name=name)
+        except LabelsException as exc:
+            click.echo(str(exc), err=True)
+            failures.append(name)
+
     for name, label in labels_to_create.items():
         try:
             context.client.create_label(repository, label=label)
@@ -253,23 +273,30 @@ def sync_cmd(
 
 
 def dryrun_echo(
-    labels_to_delete: Labels_Dict,
+    labels_to_merge: dict,
     labels_to_update: Labels_Dict,
+    labels_to_delete: Labels_Dict,
     labels_to_create: Labels_Dict,
     labels_to_ignore: Labels_Dict,
 ) -> None:
     """Print information about how labels would be updated on sync."""
 
-    if labels_to_delete:
-        click.echo(f"This would delete the following labels:")
-        for name in labels_to_delete:
-            click.echo(f"  - {name}")
+    if labels_to_merge:
+        click.echo(f"This would merge the following labels:")
+        for name in labels_to_merge:
+            click.echo(f"""\
+  - {', '.join([f"'{old}' to '{new}'" for old, new in labels_to_merge.items()])}""")
 
     if labels_to_update:
         click.echo(f"This would update the following labels:")
         for name in labels_to_update:
             click.echo(f"  - {name}")
 
+    if labels_to_delete:
+        click.echo(f"This would delete the following labels:")
+        for name in labels_to_delete:
+            click.echo(f"  - {name}")
+
     if labels_to_create:
         click.echo(f"This would create the following labels:")
         for name in labels_to_create:

src/labels/github.py

@@ -150,6 +150,76 @@ def edit_label(self, repo: Repository, *, name: str, label: Label) -> Label:
 
         return Label(**response.json())
 
+    def merge_label(self, repo: Repository, *, old_label: str, new_label: str) -> None:
+        """Merge a GitHub issue label to an existing label.
+
+        - Add the target label to all issues with the old label.
+        - The old label will be deleted while processing labels to delete.
+        """
+        logger = logging.getLogger("labels")
+        logger.debug(f"Merging label '{old_label}' to '{new_label}' in {repo.owner}/{repo.name}")  # noqa: E501
+
+        response = self.session.get(
+                f"{self.base_url}/search/issues?q=label:{old_label}+repo:{repo.owner}/{repo.name}",  # noqa: E501
+            headers={"Accept": "application/vnd.github.symmetra-preview+json"},
+        )
+
+        if response.status_code != 200:
+            raise GitHubException(
+                f"Error retrieving issues for label {old_label} in {repo.owner}/{repo.name}: "  # noqa: E501
+                f"{response.status_code} - "
+                f"{response.reason}"
+            )
+
+        json = response.json()
+
+        next_page = response.links.get('next', None)
+        while next_page:
+            logger.debug(f"Requesting {next_page}")
+            response = self.session.get(
+                    next_page['url'],
+                    headers={"Accept": "application/vnd.github.symmetra-preview+json"},
+            )
+
+            if response.status_code != 200:
+                raise GitHubException(
+                    f"Error retrieving next page of issues for label {old_label}: "
+                    f"{response.status_code} - "
+                    f"{response.reason}"
+                )
+
+            json.extend(response.json())
+            next_page = response.links.get('next', None)
+
+        for issue in json['items']:
+            response = self.session.get(
+                    f"{self.base_url}/repos/{repo.owner}/{repo.name}/issues/{issue['number']}/labels",  # noqa: E501
+                headers={"Accept": "application/vnd.github.symmetra-preview+json"},
+            )
+
+            if response.status_code != 200:
+                raise GitHubException(
+                    f"Error retrieving labels for {repo.owner}/{repo.name}/issue/{issue['number']}: "  # noqa: E501
+                    f"{response.status_code} - "
+                    f"{response.reason}"
+                )
+
+            labels = [l['name'] for l in response.json()]
+
+            if new_label not in labels:
+                response = self.session.post(
+                    f"{self.base_url}/repos/{repo.owner}/{repo.name}/issues/{issue['number']}/labels",  # noqa: E501
+                    headers={"Accept": "application/vnd.github.symmetra-preview+json"},
+                    json={'labels': [f"{new_label}"]},
+                )
+                if response.status_code != 200:
+                    raise GitHubException(
+                        f"Error adding '{new_label}' for issue {repo.owner}/{repo.name}/issues/{issue['number']}: "  # noqa: E501
+                        f"{response.status_code} - "
+                        f"{response.reason}"
+                )
+                logger.debug(f"Added label '{new_label}' to {repo.owner}/{repo.name}/issue/{issue['number']}")  # noqa: E501
+
     def delete_label(self, repo: Repository, *, name: str) -> None:
         """Delete a GitHub issue label.
 

tests/test_cli.py

@@ -194,10 +194,10 @@ def test_sync_dryrun(
     assert result.exit_code == 0
 
     output = (
-        "This would delete the following labels:\n"
-        "  - infra\n"
         "This would update the following labels:\n"
         "  - bug\n"
+        "This would delete the following labels:\n"
+        "  - infra\n"
         "This would create the following labels:\n"
         "  - dependencies\n"
         "This would NOT modify the following labels:\n"