fix(bump): skip commit step when there are no files to commit

commitizen/commands/bump.py

@@ -382,21 +382,31 @@ def __call__(self) -> None:
 
         # FIXME: check if any changes have been staged
         git.add(*updated_files)
-        c = git.commit(message, args=self._get_commit_args())
-        if self.retry and c.return_code != 0 and self.changelog_flag:
-            # Maybe pre-commit reformatted some files? Retry once
-            logger.debug("1st git.commit error: %s", c.err)
-            logger.info("1st commit attempt failed; retrying once")
-            git.add(*updated_files)
-            c = git.commit(message, args=self._get_commit_args())
-        if c.return_code != 0:
-            err = c.err.strip() or c.out
-            raise BumpCommitFailedError(f'2nd git.commit error: "{err}"')
 
-        for msg in (c.out, c.err):
-            if msg:
-                out_func = out.diagnostic if self.git_output_to_stderr else out.write
-                out_func(msg)
+        # When there is nothing for the bump to commit (e.g. ``version_provider
+        # = "scm"`` with no ``version_files`` and no ``--changelog``), skip the
+        # commit step and just tag ``HEAD``. Calling ``git commit`` here would
+        # fail with ``nothing to commit, working tree clean`` (#1530).
+        if not git.has_pending_changes():
+            out.info("No file changes; skipping bump commit and tagging HEAD.")
+        else:
+            c = git.commit(message, args=self._get_commit_args())
+            if self.retry and c.return_code != 0 and self.changelog_flag:
+                # Maybe pre-commit reformatted some files? Retry once
+                logger.debug("1st git.commit error: %s", c.err)
+                logger.info("1st commit attempt failed; retrying once")
+                git.add(*updated_files)
+                c = git.commit(message, args=self._get_commit_args())
+            if c.return_code != 0:
+                err = c.err.strip() or c.out
+                raise BumpCommitFailedError(f'2nd git.commit error: "{err}"')
+
+            for msg in (c.out, c.err):
+                if msg:
+                    out_func = (
+                        out.diagnostic if self.git_output_to_stderr else out.write
+                    )
+                    out_func(msg)
 
         c = git.tag(
             new_tag_version,

commitizen/git.py

@@ -311,6 +311,18 @@ def is_staging_clean() -> bool:
     return not bool(c.out)
 
 
+def has_pending_changes() -> bool:
+    """Check whether there are any tracked-file changes for `git commit -a` to commit.
+
+    Returns ``True`` if there are staged or unstaged modifications to tracked
+    files, ``False`` if the working tree is clean for tracked files. Untracked
+    files are intentionally ignored — they would be ignored by ``git commit -a``
+    too.
+    """
+    c = cmd.run(["git", "status", "--porcelain", "--untracked-files=no"])
+    return bool(c.out.strip())
+
+
 def is_git_project() -> bool:
     c = cmd.run(["git", "rev-parse", "--is-inside-work-tree"])
     return c.out.strip() == "true"

tests/commands/test_bump_command.py

@@ -1375,6 +1375,38 @@ def test_bump_warn_but_dont_fail_on_invalid_tags(
     assert git.tag_exist("0.4.3") is True
 
 
+def test_bump_skips_commit_when_no_files_changed(
+    tmp_commitizen_project: Path, util: UtilFixture
+):
+    """Regression test for #1530: with ``version_provider = "scm"`` and no
+    ``version_files`` / ``--changelog``, ``cz bump`` should not fail with
+    ``nothing to commit, working tree clean`` -- it should just create the
+    tag on ``HEAD``.
+    """
+    project_root = tmp_commitizen_project
+    tmp_commitizen_cfg_file = project_root / "pyproject.toml"
+    tmp_commitizen_cfg_file.write_text(
+        "\n".join(
+            [
+                "[tool.commitizen]",
+                'version_provider = "scm"',
+                'tag_format = "v$version"',
+            ]
+        ),
+    )
+    util.create_file_and_commit("feat: first feature")
+
+    util.run_cli("bump", "--yes")
+
+    assert git.tag_exist("v0.1.0") is True
+
+    util.create_file_and_commit("fix: second change")
+
+    util.run_cli("bump", "--yes")
+
+    assert git.tag_exist("v0.1.1") is True
+
+
 def test_is_initial_tag(mocker: MockFixture, tmp_commitizen_project, util: UtilFixture):
     """Test the _is_initial_tag method behavior."""
     # Create a commit but no tags