From 13334a68bc69af7e4bca43a58563b17dc8158515 Mon Sep 17 00:00:00 2001
From: Jakob Widauer <jakob.widauer@gmail.com>
Date: Wed, 10 Jul 2024 00:33:37 +0200
Subject: [PATCH] feat: add argument to limit length of commit message in
 checks

---
 commitizen/cli.py                             |  6 +++++
 commitizen/commands/check.py                  |  5 ++++
 docs/commands/check.md                        | 10 ++++++++
 tests/commands/test_check_command.py          | 25 +++++++++++++++++++
 ...shows_description_when_use_help_option.txt |  3 +++
 5 files changed, 49 insertions(+)

diff --git a/commitizen/cli.py b/commitizen/cli.py
index 1d1ebe1f6..00be6daf1 100644
--- a/commitizen/cli.py
+++ b/commitizen/cli.py
@@ -466,6 +466,12 @@ def __call__(
                         "If the message starts by one of these prefixes, "
                         "the message won't be checked against the regex",
                     },
+                    {
+                        "name": ["-l", "--message-length-limit"],
+                        "type": int,
+                        "default": 0,
+                        "help": "length limit of the commit message; 0 for no limit",
+                    },
                 ],
             },
             {
diff --git a/commitizen/commands/check.py b/commitizen/commands/check.py
index 6e98f8cb3..13b8555b6 100644
--- a/commitizen/commands/check.py
+++ b/commitizen/commands/check.py
@@ -31,6 +31,7 @@ def __init__(self, config: BaseConfig, arguments: dict[str, Any], cwd=os.getcwd(
         self.allow_abort: bool = bool(
             arguments.get("allow_abort", config.settings["allow_abort"])
         )
+        self.max_msg_length: int = arguments.get("message_length_limit", 0)
 
         # we need to distinguish between None and [], which is a valid value
 
@@ -145,4 +146,8 @@ def validate_commit_message(self, commit_msg: str, pattern: str) -> bool:
 
         if any(map(commit_msg.startswith, self.allowed_prefixes)):
             return True
+        if self.max_msg_length:
+            msg_len = len(commit_msg.partition("\n")[0].strip())
+            if msg_len > self.max_msg_length:
+                return False
         return bool(re.match(pattern, commit_msg))
diff --git a/docs/commands/check.md b/docs/commands/check.md
index c31fd085e..751a47aa2 100644
--- a/docs/commands/check.md
+++ b/docs/commands/check.md
@@ -75,3 +75,13 @@ By default, the the following prefixes are allowed: `Merge`, `Revert`, `Pull Req
 ```bash
 cz check --message MESSAGE --allowed-prefixes 'Merge' 'Revert' 'Custom Prefix'
 ```
+
+### Commit message length limit
+
+The argument `-l` (or `--message-length-limmit`) followed by a positive number, can limit the length of commit messages.
+For example, `cz check --message MESSAGE -l 3` would fail the check, since `MESSAGE` is more than 3 characters long.
+By default, the limit is set to 0, which means no limit on the length.
+
+**Note that the limit applies only to the first line of the message.***
+Specifically, for `ConventionalCommitsCz` the length only counts from the type of change to the subject,
+while the body, and the footer are not counted.
diff --git a/tests/commands/test_check_command.py b/tests/commands/test_check_command.py
index 47bdafd65..328ebd78a 100644
--- a/tests/commands/test_check_command.py
+++ b/tests/commands/test_check_command.py
@@ -427,3 +427,28 @@ def test_check_command_shows_description_when_use_help_option(
 
     out, _ = capsys.readouterr()
     file_regression.check(out, extension=".txt")
+
+
+def test_check_command_with_message_length_limit(config, mocker: MockFixture):
+    success_mock = mocker.patch("commitizen.out.success")
+    message = "fix(scope): some commit message"
+    check_cmd = commands.Check(
+        config=config,
+        arguments={"message": message, "message_length_limit": len(message) + 1},
+    )
+
+    check_cmd()
+    success_mock.assert_called_once()
+
+
+def test_check_command_with_message_length_limit_exceeded(config, mocker: MockFixture):
+    error_mock = mocker.patch("commitizen.out.error")
+    message = "fix(scope): some commit message"
+    check_cmd = commands.Check(
+        config=config,
+        arguments={"message": message, "message_length_limit": len(message) - 1},
+    )
+
+    with pytest.raises(InvalidCommitMessageError):
+        check_cmd()
+        error_mock.assert_called_once()
diff --git a/tests/commands/test_check_command/test_check_command_shows_description_when_use_help_option.txt b/tests/commands/test_check_command/test_check_command_shows_description_when_use_help_option.txt
index 56e42388d..74b9df719 100644
--- a/tests/commands/test_check_command/test_check_command_shows_description_when_use_help_option.txt
+++ b/tests/commands/test_check_command/test_check_command_shows_description_when_use_help_option.txt
@@ -1,6 +1,7 @@
 usage: cz check [-h]
                 [--commit-msg-file COMMIT_MSG_FILE | --rev-range REV_RANGE | -m MESSAGE]
                 [--allow-abort] [--allowed-prefixes [ALLOWED_PREFIXES ...]]
+                [-l MESSAGE_LENGTH_LIMIT]
 
 validates that a commit message matches the commitizen schema
 
@@ -20,3 +21,5 @@ options:
                         allowed commit message prefixes. If the message starts
                         by one of these prefixes, the message won't be checked
                         against the regex
+  -l MESSAGE_LENGTH_LIMIT, --message-length-limit MESSAGE_LENGTH_LIMIT
+                        length limit of the commit message; 0 for no limit