feat: Add option in bump command to redirect git output to stderr

This is useful used in conjunction with `--changelog-to-stdout` if you
don't need/want the resulting output to contain the `git commit` log
messages.

commitizen/cli.py

@@ -186,6 +186,12 @@
                         "default": False,
                         "help": "Output changelog to the stdout",
                     },
+                    {
+                        "name": ["--git-output-to-stderr"],
+                        "action": "store_true",
+                        "default": False,
+                        "help": "Redirect git output to stderr",
+                    },
                     {
                         "name": ["--retry"],
                         "action": "store_true",

commitizen/commands/bump.py

@@ -59,6 +59,7 @@ def __init__(self, config: BaseConfig, arguments: dict):
             "update_changelog_on_bump"
         )
         self.changelog_to_stdout = arguments["changelog_to_stdout"]
+        self.git_output_to_stderr = arguments["git_output_to_stderr"]
         self.no_verify = arguments["no_verify"]
         self.check_consistency = arguments["check_consistency"]
         self.retry = arguments["retry"]
@@ -329,9 +330,15 @@ def __call__(self):  # noqa: C901
             raise BumpCommitFailedError(f'2nd git.commit error: "{c.err.strip()}"')
 
         if c.out:
-            out.write(c.out)
+            if self.git_output_to_stderr:
+                out.diagnostic(c.out)
+            else:
+                out.write(c.out)
         if c.err:
-            out.write(c.err)
+            if self.git_output_to_stderr:
+                out.diagnostic(c.err)
+            else:
+                out.write(c.err)
 
         c = git.tag(
             new_tag_version,

docs/bump.md

@@ -57,7 +57,7 @@ usage: cz bump [-h] [--dry-run] [--files-only] [--local-version] [--changelog]
                [--bump-message BUMP_MESSAGE] [--prerelease {alpha,beta,rc}]
                [--devrelease DEVRELEASE] [--increment {MAJOR,MINOR,PATCH}]
                [--check-consistency] [--annotated-tag] [--gpg-sign]
-               [--changelog-to-stdout] [--retry] [--major-version-zero]
+               [--changelog-to-stdout] [--git-output-to-stderr] [--retry] [--major-version-zero]
                [MANUAL_VERSION]
 
 positional arguments:
@@ -91,6 +91,8 @@ options:
   --gpg-sign, -s        sign tag instead of lightweight one
   --changelog-to-stdout
                         Output changelog to the stdout
+  --git-output-to-stderr
+                        Redirect git output to stderr
   --retry               retry commit if it fails the 1st time
   --major-version-zero  keep major version at zero, even for breaking changes
   --prerelease-offset   start pre-releases with this offset
@@ -196,6 +198,13 @@ Example:
 cz bump --changelog --changelog-to-stdout > body.md
 ```
 
+### `--git-output-to-stderr`
+
+If `--git-output-to-stderr` is used, git commands output is redirected to stderr.
+
+This command is useful when used with `--changelog-to-stdout` and piping the output to a file,
+and you don't want the `git commit` output polluting  the stdout.
+
 ### `--retry`
 
 If you use tools like [pre-commit](https://pre-commit.com/), add this flag.

tests/commands/test_bump_command.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import inspect
+import re
 import sys
 from unittest.mock import MagicMock, call
 
@@ -597,6 +598,34 @@ def test_bump_with_changelog_to_stdout_dry_run_arg(
     assert "0.2.0" in out
 
 
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_without_git_to_stdout_arg(mocker: MockFixture, capsys, changelog_path):
+    create_file_and_commit("feat(user): this should appear in stdout")
+    testargs = ["cz", "bump", "--yes"]
+    mocker.patch.object(sys, "argv", testargs)
+    cli.main()
+    out, _ = capsys.readouterr()
+
+    assert (
+        re.search(r"^\[master \w+] bump: version 0.1.0 → 0.2.0", out, re.MULTILINE)
+        is not None
+    )
+
+
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_with_git_to_stdout_arg(mocker: MockFixture, capsys, changelog_path):
+    create_file_and_commit("feat(user): this should appear in stdout")
+    testargs = ["cz", "bump", "--yes", "--git-output-to-stderr"]
+    mocker.patch.object(sys, "argv", testargs)
+    cli.main()
+    out, _ = capsys.readouterr()
+
+    assert (
+        re.search(r"^\[master \w+] bump: version 0.1.0 → 0.2.0", out, re.MULTILINE)
+        is None
+    )
+
+
 @pytest.mark.parametrize(
     "version_filepath, version_regex, version_file_content",
     [