feat: option to skip merge commits format check

README.md

@@ -134,14 +134,15 @@ usage: conventional-pre-commit [-h] [--force-scope] [--scopes SCOPES] [--strict]
 Check a git commit message for Conventional Commits formatting.
 
 positional arguments:
-  types            Optional list of types to support
-  input            A file containing a git commit message
+  types                 Optional list of types to support
+  input                 A file containing a git commit message
 
 options:
-  -h, --help       show this help message and exit
-  --force-scope    Force commit to have scope defined.
-  --scopes SCOPES  Optional list of scopes to support. Scopes should be separated by commas with no spaces (e.g. api,client)
-  --strict         Force commit to strictly follow Conventional Commits formatting. Disallows fixup! style commits.
+  -h, --help            show this help message and exit
+  --force-scope         Force commit to have scope defined.
+  --scopes SCOPES       Optional list of scopes to support. Scopes should be separated by commas with no spaces (e.g. api,client)
+  --strict              Force commit to strictly follow Conventional Commits formatting. Disallows fixup! style commits.
+  --skip-merge-commits  Do not check format for merge commits.
 ```
 
 Supply arguments on the command-line, or via the pre-commit `hooks.args` property:
@@ -153,7 +154,7 @@ repos:
     hooks:
       - id: conventional-pre-commit
         stages: [commit-msg]
-        args: [--strict, --force-scope, feat, fix, chore, test, custom]
+        args: [--strict, --skip-merge-commits, --force-scope, feat, fix, chore, test, custom]
 ```
 
 **NOTE:** when using as a pre-commit hook, `input` is supplied automatically (with the current commit's message).

conventional_pre_commit/format.py

@@ -125,3 +125,14 @@ def has_autosquash_prefix(input):
     regex = re.compile(pattern, re.DOTALL)
 
     return bool(regex.match(input))
+
+
+def is_merge_commit(input):
+    """
+    Returns True if input starts with 'Merge branch '.
+
+    It doesn't check whether the rest of the input matches Conventional Commits
+    formatting.
+    """
+
+    return input.startswith("Merge branch ")

conventional_pre_commit/hook.py

@@ -34,6 +34,12 @@ def main(argv=[]):
         action="store_true",
         help="Force commit to strictly follow Conventional Commits formatting. Disallows fixup! style commits.",
     )
+    parser.add_argument(
+        "--skip-merge-commits",
+        action="store_true",
+        dest="skip_merge_commits",
+        help="Do not check format for merge commits.",
+    )
 
     if len(argv) < 1:
         argv = sys.argv[1:]
@@ -62,6 +68,10 @@ def main(argv=[]):
     else:
         scopes = args.scopes
 
+    if args.skip_merge_commits:
+        if format.is_merge_commit(message):
+            return RESULT_SUCCESS
+
     if not args.strict:
         if format.has_autosquash_prefix(message):
             return RESULT_SUCCESS

tests/conftest.py

@@ -44,6 +44,11 @@ def fixup_commit_path():
     return get_message_path("fixup_commit")
 
 
+@pytest.fixture
+def merge_commit_path():
+    return get_message_path("merge_commit")
+
+
 @pytest.fixture
 def conventional_commit_bad_multi_line_path():
     return get_message_path("conventional_commit_bad_multi_line")

tests/messages/merge_commit

@@ -0,0 +1 @@
+Merge branch '2.x.x' into '1.x.x'

tests/test_format.py

@@ -125,6 +125,10 @@ def test_r_autosquash_prefixes():
         assert regex.match(prefix)
 
 
+def test_merge_commit():
+    assert format.is_merge_commit("Merge branch '2.x.x' into '1.x.x'")
+
+
 def test_conventional_types__default():
     result = format.conventional_types()
 

tests/test_hook.py

@@ -82,6 +82,18 @@ def test_main_fail__fixup_commit(fixup_commit_path):
     assert result == RESULT_FAIL
 
 
+def test_main_fail__merge_commit(merge_commit_path):
+    result = main([merge_commit_path])
+
+    assert result == RESULT_FAIL
+
+
+def test_main_success__merge_commit(merge_commit_path):
+    result = main(["--skip-merge-commits", merge_commit_path])
+
+    assert result == RESULT_SUCCESS
+
+
 def test_main_success__conventional_commit_multi_line(conventional_commit_multi_line_path):
     result = main([conventional_commit_multi_line_path])