Adds --increment option to show subcommand

- when specified it increments the current version and adds `new_version` to the available output.

bumpversion/cli.py

@@ -272,12 +272,20 @@ def bump(
     default="default",
     help="Config file to read most of the variables from.",
 )
-def show(args: List[str], config_file: Optional[str], format_: str) -> None:
+@click.option(
+    "-i",
+    "--increment",
+    required=False,
+    envvar="BUMPVERSION_INCREMENT",
+    type=str,
+    help="Increment the version part and add `new_version` to the configuration.",
+)
+def show(args: List[str], config_file: Optional[str], format_: str, increment: Optional[str]) -> None:
     """Show current configuration information."""
     found_config_file = find_config_file(config_file)
     config = get_configuration(found_config_file)
 
     if not args:
-        do_show("all", config=config, format_=format_)
+        do_show("all", config=config, format_=format_, increment=increment)
     else:
-        do_show(*args, config=config, format_=format_)
+        do_show(*args, config=config, format_=format_, increment=increment)

bumpversion/show.py

@@ -121,9 +121,16 @@ def log_list(config: Config, version_part: Optional[str], new_version: Optional[
         print_info(f"{key}={value}")
 
 
-def do_show(*args, config: Config, format_: str = "default") -> None:
+def do_show(*args, config: Config, format_: str = "default", increment: Optional[str] = None) -> None:
     """Show current version or configuration information."""
     config_dict = config.dict()
+    ctx = get_context(config)
+
+    if increment:
+        version = config.version_config.parse(config.current_version)
+        next_version = get_next_version(version, config, increment, None)
+        next_version_str = config.version_config.serialize(next_version, ctx)
+        config_dict["new_version"] = next_version_str
 
     try:
         if "all" in args or not args:

tests/test_cli.py

@@ -298,6 +298,25 @@ def test_show(tmp_path: Path, fixtures_path: Path):
     assert result.output.splitlines(keepends=False) == ["1.0.0"]
 
 
+def test_show_and_increment(tmp_path: Path, fixtures_path: Path):
+    """The show subcommand should incrment the version and display it."""
+    # Arrange
+    config_path = tmp_path / "pyproject.toml"
+    toml_path = fixtures_path / "basic_cfg.toml"
+    shutil.copy(toml_path, config_path)
+    runner: CliRunner = CliRunner()
+
+    with inside_dir(tmp_path):
+        result: Result = runner.invoke(cli.cli, ["show", "new_version", "--increment", "minor"])
+
+    if result.exit_code != 0:
+        print(result.output)
+        print(result.exception)
+
+    assert result.exit_code == 0
+    assert result.output.splitlines(keepends=False) == ["1.1.0-dev"]
+
+
 def test_show_no_args(tmp_path: Path, fixtures_path: Path):
     """The show subcommand should list the entire configuration."""
     # Arrange

tests/test_show.py

@@ -156,3 +156,15 @@ def test_do_show(
         show.do_show(config=conf, format_=format_, *req_args)
     captured = capsys.readouterr()
     assert captured.out.strip() == expected
+
+
+def test_do_show_increment(tmp_path: Path, fixtures_path: Path, capsys: pytest.CaptureFixture) -> None:
+    """Test the show method with increment."""
+    config_path = tmp_path / "pyproject.toml"
+    toml_path = fixtures_path / "basic_cfg.toml"
+    shutil.copy(toml_path, config_path)
+    with inside_dir(tmp_path):
+        conf = config.get_configuration(config_file=fixtures_path.joinpath(config_path))
+        show.do_show("current_version", "new_version", config=conf, format_="default", increment="minor")
+    captured = capsys.readouterr()
+    assert captured.out.strip() == "{'current_version': '1.0.0', 'new_version': '1.1.0-dev'}"