Allow conventional commits

Some projects use 'conventional commits' so let's make it
easier for them to use this Action,
by ignoring the subject/tag.

.github/workflows/test-action.yml

@@ -0,0 +1,22 @@
+name: Python package
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-20.04
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+          python -m textblob.download_corpora
+      - name: Run tests
+        run: |
+          python -m pytest bad_commit_message_blocker_tests.py

.gitignore

@@ -1 +1,2 @@
-__pycache__
+__pycache__
+.venv

README.md

@@ -94,4 +94,6 @@ jobs:
           body_limit: 100
           # Optionally set the remote branch name to merge (default `master`)
           remote_branch: dev
+          # Optionally allow "conventional commits" (default `false`)
+          allow_conventional_commits: true
 ```

action.yml

@@ -9,6 +9,10 @@ inputs:
     description: 'The maximum allowed length for a line in the commit body'
     required: true
     default: 72
+  conventional_commit:
+    description: 'Whether to allow conventional commits, e.g. "feat: add new feature"'
+    required: false
+    default: false
   remote_branch:
     description: 'The name of the remote branch you are trying to merge with'
     required: true

bad_commit_message_blocker.py

@@ -97,12 +97,10 @@ def check_subject_uses_imperative(commit_message):
     third_person_blob = TextBlob(third_person_prefix + first_line)
     non_third_person_blob = TextBlob(non_third_person_prefix + first_line)
 
-    first_word, third_person_result = third_person_blob.tags[
-        words_in_third_person_prefix_blob
-    ]
-    _, non_third_person_result = non_third_person_blob.tags[
-        words_in_non_third_person_prefix_blob
-    ]
+    tags = third_person_blob.tags
+    first_word, third_person_result = tags[words_in_third_person_prefix_blob]
+    tags = non_third_person_blob.tags
+    _, non_third_person_result = tags[words_in_non_third_person_prefix_blob]
 
     # We need to determine whether the first word is a non-third person verb
     # when parsed in a non-third person blob. However, there were some
@@ -167,6 +165,12 @@ def check(
     return all_rules_verified
 
 
+def strip_prefix(commit_message):
+    if ":" in commit_message:
+        return commit_message[commit_message.index(":") + 1 :].strip()
+    return commit_message
+
+
 def main():
     parser_description = (
         "Bad commit message blocker: Avoid bad commit messages in your repository"
@@ -183,6 +187,13 @@ def main():
         help="The maximum allowed length for a line in the commit body",
         default=DEFAULT_BODY_LIMIT,
     )
+    parser.add_argument(
+        "--conventional-commit",
+        help="Whether the commit message follows the conventional commit format,"
+        " e.g. 'feat: add new feature'",
+        type=bool,
+        default=False,
+    )
     args = parser.parse_args()
 
     commit_message = args.message.strip()
@@ -197,6 +208,9 @@ def main():
         + CliColors.ENDC
     )
 
+    if args.conventional_commit:
+        commit_message = strip_prefix(commit_message)
+
     all_rules_verified = check(
         commit_message, int(args.subject_limit), int(args.body_limit)
     )

bad_commit_message_blocker_tests.py

@@ -144,6 +144,16 @@ def test_checkBodyExplainsWhatAndWhy_WhenCalled_WillReturnTrue(self):
         test_input = "Something that does not matter"
         self.assertTrue(blocker.check_body_explains_what_and_why(test_input))
 
+    def test_stripPrefix_WhenColonInMessage_WillReturnEverythingAfterColon(self):
+        test_input = "feat: add new feature"
+        expected_output = "add new feature"
+        self.assertEqual(blocker.strip_prefix(test_input), expected_output)
+
+    def test_stripPrefix_WhenNoColonInMessage_WillReturnWholeMessage(self):
+        test_input = "add new feature"
+        expected_output = "add new feature"
+        self.assertEqual(blocker.strip_prefix(test_input), expected_output)
+
 
 if __name__ == "__main__":
     unittest.main()

entrypoint.sh

@@ -20,5 +20,6 @@ while read -r commit_hash; do
     python3 $script_dir/bad_commit_message_blocker.py \
         --message "${commit_message}" \
         --subject-limit "${INPUT_SUBJECT_LIMIT}" \
-        --body-limit "${INPUT_BODY_LIMIT}"
+        --body-limit "${INPUT_BODY_LIMIT}" \
+        --conventional-commit "${INPUT_CONVENTIONAL_COMMIT}"
 done <<< "$commits_since_master"

requirements.txt

@@ -0,0 +1,2 @@
+textblob==0.18.0.post0
+pytest==8.3.2