fix(cz_customize): default commit_parser extracts change_type

CustomizeCommitsCz previously inherited the `commit_parser =
r"(?P<message>.*)"` default from `BaseCommitizen`. That default
matches everything but does not capture a `change_type` named group,
so even when a `cz_customize` user configured `changelog_pattern`,
`change_type_map` and `change_type_order`, the changelog generator
could not group commits and emitted a single ungrouped bullet list.

Set a conventional-commits-style default that captures
`change_type`, `scope`, `breaking` and `message` named groups.
Users with a different commit format can still override via
`customize.commit_parser`.

End-to-end check on the exact reproducer from the issue now produces a
properly grouped changelog:

    ## Unreleased
    ### feat
    - **DL-4567**: new feature test
    ### fix
    - **DL-1234**: qweqwe
    ### chore
    - update deps

Closes #466

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bearomorphism

commitizen/cz/customize/customize.py

@@ -29,6 +29,18 @@ class CustomizeCommitsCz(BaseCommitizen):
     bump_map = defaults.BUMP_MAP
     bump_map_major_version_zero = defaults.BUMP_MAP_MAJOR_VERSION_ZERO
     change_type_order = defaults.CHANGE_TYPE_ORDER
+    # A conventional-commits-style default so that ``cz_customize`` users who
+    # configure ``changelog_pattern`` (and optionally ``change_type_map`` /
+    # ``change_type_order``) but no explicit ``commit_parser`` still get a
+    # changelog grouped by change type. It captures any word as
+    # ``change_type``, an optional scope, an optional ``!`` breaking marker,
+    # and the message subject. Users with a different commit format can
+    # still override this via ``customize.commit_parser`` (#466).
+    commit_parser = (
+        r"^(?P<change_type>\w+)"
+        r"(?:\((?P<scope>[^()\r\n]*)\))?"
+        r"(?P<breaking>!)?:\s*(?P<message>.*)$"
+    )
 
     def __init__(self, config: BaseConfig) -> None:
         super().__init__(config)

tests/test_cz_customize.py

@@ -591,6 +591,49 @@ def test_commit_parser_unicode(config_with_unicode):
     )
 
 
+def test_commit_parser_default_extracts_change_type():
+    """Regression test for #466: when ``customize.commit_parser`` is not set,
+    the default must still extract a ``change_type`` named group so that the
+    changelog can be grouped by type (e.g. ``### Feat``, ``### Fix``).
+    Previously the default was ``r"(?P<message>.*)"`` -- inherited from
+    ``BaseCommitizen`` -- which left every commit ungrouped.
+    """
+    import re
+
+    config = BaseConfig()
+    config.settings.update(
+        {
+            "name": "cz_customize",
+            "customize": {
+                # No ``commit_parser`` provided -- exercises the new default.
+                "changelog_pattern": r"^(feat|fix|chore)(\(.+\))?(!)?",
+            },
+        }
+    )
+    cz = CustomizeCommitsCz(config)
+
+    pattern = re.compile(cz.commit_parser, re.MULTILINE)
+
+    feat = pattern.match("feat(scope): a feature")
+    assert feat is not None
+    assert feat.group("change_type") == "feat"
+    assert feat.group("scope") == "scope"
+    assert feat.group("breaking") is None
+    assert feat.group("message") == "a feature"
+
+    breaking = pattern.match("fix!: breaking fix")
+    assert breaking is not None
+    assert breaking.group("change_type") == "fix"
+    assert breaking.group("breaking") == "!"
+    assert breaking.group("message") == "breaking fix"
+
+    no_scope = pattern.match("chore: tidy up")
+    assert no_scope is not None
+    assert no_scope.group("change_type") == "chore"
+    assert no_scope.group("scope") is None
+    assert no_scope.group("message") == "tidy up"
+
+
 def test_changelog_pattern(config):
     cz = CustomizeCommitsCz(config)
     assert cz.changelog_pattern == "^(feature|bug fix)?(!)?"