feature: changelog_message_build_hook can remove message by returning a falsy value

commitizen/changelog.py

@@ -166,7 +166,8 @@ def generate_tree_from_commits(
                 change_type = change_type_map.get(change_type, change_type)
             if changelog_message_builder_hook:
                 parsed_message = changelog_message_builder_hook(parsed_message, commit)
-            changes[change_type].append(parsed_message)
+            if parsed_message:
+                changes[change_type].append(parsed_message)
 
         # Process body from commit message
         body_parts = commit.body.split("\n\n")
@@ -179,7 +180,12 @@ def generate_tree_from_commits(
             change_type = parsed_message_body.pop("change_type", None)
             if change_type_map:
                 change_type = change_type_map.get(change_type, change_type)
-            changes[change_type].append(parsed_message_body)
+            if changelog_message_builder_hook:
+                parsed_message_body = changelog_message_builder_hook(
+                    parsed_message_body, commit
+                )
+            if parsed_message_body:
+                changes[change_type].append(parsed_message_body)
 
     yield {"version": current_tag_name, "date": current_tag_date, "changes": changes}
 

commitizen/commands/changelog.py

@@ -9,6 +9,7 @@
 from commitizen import bump, changelog, defaults, factory, git, out
 
 from commitizen.config import BaseConfig
+from commitizen.cz.base import MessageBuilderHook
 from commitizen.exceptions import (
     DryRunExit,
     NoCommitsFoundError,
@@ -145,7 +146,7 @@ def __call__(self):
         unreleased_version = self.unreleased_version
         changelog_meta = changelog.Metadata()
         change_type_map: dict | None = self.change_type_map
-        changelog_message_builder_hook: Callable | None = (
+        changelog_message_builder_hook: MessageBuilderHook | None = (
             self.cz.changelog_message_builder_hook
         )
         merge_prerelease = self.merge_prerelease

commitizen/cz/base.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from abc import ABCMeta, abstractmethod
-from typing import Any, Callable
+from typing import Any, Callable, Protocol
 
 from jinja2 import BaseLoader, PackageLoader
 from prompt_toolkit.styles import Style, merge_styles
@@ -11,6 +11,12 @@
 from commitizen.defaults import Questions
 
 
+class MessageBuilderHook(Protocol):
+    def __call__(
+        self, message: dict[str, Any], commit: git.GitCommit
+    ) -> dict[str, Any] | None: ...
+
+
 class BaseCommitizen(metaclass=ABCMeta):
     bump_pattern: str | None = None
     bump_map: dict[str, str] | None = None
@@ -37,9 +43,7 @@ class BaseCommitizen(metaclass=ABCMeta):
     change_type_order: list[str] | None = None
 
     # Executed per message parsed by the commitizen
-    changelog_message_builder_hook: None | (Callable[[dict, git.GitCommit], dict]) = (
-        None
-    )
+    changelog_message_builder_hook: MessageBuilderHook | None = None
 
     # Executed only at the end of the changelog generation
     changelog_hook: Callable[[str, str | None], str] | None = None

docs/bump.md

@@ -147,13 +147,13 @@ by their precedence and showcase how a release might flow through a development
 
 ### `--increment-mode`
 
-By default, `--increment-mode` is set to `linear`, which ensures taht bumping pre-releases _maintains linearity_: 
-bumping of a pre-release with lower precedence than the current pre-release phase maintains the current phase of 
-higher precedence. For example, if the current version is `1.0.0b1` then bumping with `--prerelease alpha` will 
+By default, `--increment-mode` is set to `linear`, which ensures that bumping pre-releases _maintains linearity_:
+bumping of a pre-release with lower precedence than the current pre-release phase maintains the current phase of
+higher precedence. For example, if the current version is `1.0.0b1` then bumping with `--prerelease alpha` will
 continue to bump the “beta” phase.
 
-Setting `--increment-mode` to `exact` instructs `cz bump` to instead apply the 
-exact changes that have been specified with `--increment` or determined from the commit log. For example, 
+Setting `--increment-mode` to `exact` instructs `cz bump` to instead apply the
+exact changes that have been specified with `--increment` or determined from the commit log. For example,
 `--prerelease beta` will always result in a `b` tag, and `--increment PATCH` will always increase the patch component.
 
 Below are some examples that illustrate the difference in behavior:

docs/customization.md

@@ -318,7 +318,7 @@ You can customize it of course, and this are the variables you need to add to yo
 | `commit_parser`                  | `str`                                                                    | NO       | Regex which should provide the variables explained in the [changelog description][changelog-des]                                                                                                                    |
 | `changelog_pattern`              | `str`                                                                    | NO       | Regex to validate the commits, this is useful to skip commits that don't meet your ruling standards like a Merge. Usually the same as bump_pattern                                                                  |
 | `change_type_map`                | `dict`                                                                   | NO       | Convert the title of the change type that will appear in the changelog, if a value is not found, the original will be provided                                                                                      |
-| `changelog_message_builder_hook` | `method: (dict, git.GitCommit) -> dict`                                  | NO       | Customize with extra information your message output, like adding links, this function is executed per parsed commit. Each GitCommit contains the following attrs: `rev`, `title`, `body`, `author`, `author_email` |
+| `changelog_message_builder_hook` | `method: (dict, git.GitCommit) -> dict | None`                                  | NO       | Customize with extra information your message output, like adding links, this function is executed per parsed commit. Each GitCommit contains the following attrs: `rev`, `title`, `body`, `author`, `author_email`. Returning a falsy value ignore the commit. |
 | `changelog_hook`                 | `method: (full_changelog: str, partial_changelog: Optional[str]) -> str` | NO       | Receives the whole and partial (if used incremental) changelog. Useful to send slack messages or notify a compliance department. Must return the full_changelog                                                     |
 
 ```python
@@ -339,7 +339,7 @@ class StrangeCommitizen(BaseCommitizen):
 
     def changelog_message_builder_hook(
         self, parsed_message: dict, commit: git.GitCommit
-    ) -> dict:
+    ) -> dict | None:
         rev = commit.rev
         m = parsed_message["message"]
         parsed_message[

tests/test_changelog.py

@@ -1,3 +1,5 @@
+import re
+
 from pathlib import Path
 
 import pytest
@@ -1319,6 +1321,32 @@ def changelog_message_builder_hook(message: dict, commit: git.GitCommit) -> dict
     assert "[link](github.com/232323232) Commitizen author@cz.dev" in result
 
 
+def test_changelog_message_builder_hook_can_remove_commits(
+    gitcommits, tags, any_changelog_format: ChangelogFormat
+):
+    def changelog_message_builder_hook(message: dict, commit: git.GitCommit):
+        return None
+
+    parser = ConventionalCommitsCz.commit_parser
+    changelog_pattern = ConventionalCommitsCz.changelog_pattern
+    loader = ConventionalCommitsCz.template_loader
+    template = any_changelog_format.template
+    tree = changelog.generate_tree_from_commits(
+        gitcommits,
+        tags,
+        parser,
+        changelog_pattern,
+        changelog_message_builder_hook=changelog_message_builder_hook,
+    )
+    result = changelog.render_changelog(tree, loader, template)
+
+    RE_HEADER = re.compile(r"^## v?\d+\.\d+\.\d+(\w)* \(\d{4}-\d{2}-\d{2}\)$")
+    # Rendered changelog should be empty, only containing version headers
+    for no, line in enumerate(result.splitlines()):
+        if line := line.strip():
+            assert RE_HEADER.match(line), f"Line {no} should not be there: {line}"
+
+
 def test_get_smart_tag_range_returns_an_extra_for_a_range(tags):
     start, end = (
         tags[0],