feat: Validate multi-line messages

The documented conventional commit specification states that on
multi-line commit message there must be a blank line between the title
and the body.

To avoid a breaking change this has been toggled using the strict
option, in the next major release this toggle will be removed.

Author: grahamhar

conventional_pre_commit/format.py

@@ -40,8 +40,13 @@ def r_delim():
 
 
 def r_subject():
-    """Regex str for subject line, body, footer."""
-    return r" .+"
+    """Regex str for subject line."""
+    return r" .+$"
+
+
+def r_body():
+    """Regex str for the body"""
+    return r"(?P<multi>\r?\n(?P<sep>^$\r?\n)?.+)?"
 
 
 def r_autosquash_prefixes():
@@ -56,18 +61,23 @@ def conventional_types(types=[]):
     return types
 
 
-def is_conventional(input, types=DEFAULT_TYPES, optional_scope=True):
+def is_conventional(input, types=DEFAULT_TYPES, optional_scope=True, is_strict=False):
     """
     Returns True if input matches Conventional Commits formatting
     https://www.conventionalcommits.org
 
     Optionally provide a list of additional custom types.
     """
     types = conventional_types(types)
-    pattern = f"^({r_types(types)}){r_scope(optional_scope)}{r_delim()}{r_subject()}$"
-    regex = re.compile(pattern, re.DOTALL)
+    pattern = f"^({r_types(types)}){r_scope(optional_scope)}{r_delim()}{r_subject()}{r_body()}"
+    regex = re.compile(pattern, re.MULTILINE)
 
-    return bool(regex.match(input))
+    result = regex.match(input)
+    is_valid_subject = bool(result)
+    if is_valid_subject and is_strict and result.group("multi") and not result.group("sep"):
+        is_valid_subject = False
+
+    return is_valid_subject
 
 
 def has_autosquash_prefix(input):

conventional_pre_commit/hook.py

@@ -54,7 +54,7 @@ def main(argv=[]):
         if format.has_autosquash_prefix(message):
             return RESULT_SUCCESS
 
-    if format.is_conventional(message, args.types, args.optional_scope):
+    if format.is_conventional(message, args.types, args.optional_scope, args.strict):
         return RESULT_SUCCESS
     else:
         print(
@@ -64,7 +64,7 @@ def main(argv=[]):
         {Colors.LBLUE}https://www.conventionalcommits.org/{Colors.YELLOW}
 
         Conventional Commits start with one of the below types, followed by a colon,
-        followed by the commit message:{Colors.RESTORE}
+        followed by the commit subject and an optional body seperated by a blank line:{Colors.RESTORE}
 
             {" ".join(format.conventional_types(args.types))}
 
@@ -78,7 +78,14 @@ def main(argv=[]):
 
         {Colors.YELLOW}Example commit with scope in parentheses after the type for more context:{Colors.RESTORE}
 
-            fix(account): remove infinite loop"""
+            fix(account): remove infinite loop
+
+        {Colors.YELLOW}Example commit with a body
+
+            fix: remove infinite loop
+
+            Additional information on the issue caused by the infinite loop
+            """
         )
         return RESULT_FAIL
 

tests/conftest.py

@@ -42,3 +42,13 @@ def conventional_gbk_commit_path():
 @pytest.fixture
 def fixup_commit_path():
     return get_message_path("fixup_commit")
+
+
+@pytest.fixture
+def conventional_commit_bad_multi_line_path():
+    return get_message_path("conventional_commit_bad_multi_line")
+
+
+@pytest.fixture
+def conventional_commit_multi_line_path():
+    return get_message_path("conventional_commit_multi_line")

tests/messages/conventional_commit_bad_multi_line

@@ -0,0 +1,2 @@
+fix: message
+no blank line

tests/messages/conventional_commit_multi_line

@@ -0,0 +1,3 @@
+fix: message
+
+A blank line is there

tests/test_format.py

@@ -162,13 +162,64 @@ def test_is_conventional__with_scope():
     assert format.is_conventional(input)
 
 
-def test_is_conventional__body_multiline():
+def test_is_conventional__body_multiline_not_strict():
     input = """feat(scope): message
 
     more message
     """
 
-    assert format.is_conventional(input)
+    assert format.is_conventional(input, is_strict=False)
+
+
+def test_is_conventional__body_multiline_no_body_not_strict():
+    input = """feat(scope): message
+
+    """
+    assert format.is_conventional(input, is_strict=False)
+
+
+def test_is_conventional__body_multiline_body_bad_type_strict():
+    input = """wrong: message
+
+    more_message
+    """
+
+    assert not format.is_conventional(input, is_strict=True)
+
+
+def test_is_conventional__bad_body_multiline_not_strict():
+    input = """feat(scope): message
+    more message
+    """
+
+    assert format.is_conventional(input, is_strict=False)
+
+
+def test_is_conventional__bad_body_multiline_strict():
+    input = """feat(scope): message
+    more message
+    """
+
+    assert not format.is_conventional(input, is_strict=True)
+
+
+def test_is_conventional__body_multiline_strict():
+    input = """feat(scope): message
+
+    more message
+    """
+
+    assert format.is_conventional(input, is_strict=True)
+
+
+def test_is_conventional__bad_body_multiline_paragraphs_strict():
+    input = """feat(scope): message
+    more message
+
+    more body message
+    """
+
+    assert not format.is_conventional(input, is_strict=True)
 
 
 @pytest.mark.parametrize("char", ['"', "'", "`", "#", "&"])

tests/test_hook.py

@@ -116,3 +116,21 @@ def test_main_success__fail_commit(cmd, fixup_commit_path):
     result = subprocess.call((cmd, "--strict", fixup_commit_path))
 
     assert result == RESULT_FAIL
+
+
+def test_main_success__conventional_commit_multi_line(cmd, conventional_commit_multi_line_path):
+    result = subprocess.call((cmd, conventional_commit_multi_line_path))
+
+    assert result == RESULT_SUCCESS
+
+
+def test_main_success__conventional_commit_bad_multi_line(cmd, conventional_commit_bad_multi_line_path):
+    result = subprocess.call((cmd, conventional_commit_bad_multi_line_path))
+
+    assert result == RESULT_SUCCESS
+
+
+def test_main_success__conventional_commit_bad_multi_line_strict(cmd, conventional_commit_bad_multi_line_path):
+    result = subprocess.call((cmd, "--strict", conventional_commit_bad_multi_line_path))
+
+    assert result == RESULT_FAIL