Fix metavar for Choice options when show_choices=False

CHANGES.rst

@@ -5,6 +5,9 @@ Version 8.2.0
 
 Unreleased
 
+-   Show the ``types.ParamType.name`` for ``types.Choice`` options within
+    ``--help`` message if ``show_choices=False`` is specified.
+    :issue:`2356`
 -   Drop support for Python 3.7. :pr:`2588`
 -   Use modern packaging metadata with ``pyproject.toml`` instead of ``setup.cfg``.
     :pr:`326`

src/click/types.py

@@ -258,7 +258,13 @@ def to_info_dict(self) -> dict[str, t.Any]:
         return info_dict
 
     def get_metavar(self, param: Parameter) -> str:
-        choices_str = "|".join(self.choices)
+        if param.param_type_name == "option" and not param.show_choices:  # type: ignore
+            choice_metavars = [
+                convert_type(type(choice)).name.upper() for choice in self.choices
+            ]
+            choices_str = "|".join([*dict.fromkeys(choice_metavars)])
+        else:
+            choices_str = "|".join([str(i) for i in self.choices])
 
         # Use curly braces to indicate a required argument.
         if param.required and param.param_type_name == "argument":

tests/test_options.py

@@ -918,3 +918,39 @@ def test_invalid_flag_combinations(runner, kwargs, message):
         click.Option(["-a"], **kwargs)
 
     assert message in str(e.value)
+
+
+@pytest.mark.parametrize(
+    ("choices", "metavars"),
+    [
+        pytest.param(["foo", "bar"], "[TEXT]", id="text choices"),
+        pytest.param([1, 2], "[INTEGER]", id="int choices"),
+        pytest.param([1.0, 2.0], "[FLOAT]", id="float choices"),
+        pytest.param([True, False], "[BOOLEAN]", id="bool choices"),
+        pytest.param(["foo", 1], "[TEXT|INTEGER]", id="text/int choices"),
+    ],
+)
+def test_usage_show_choices(runner, choices, metavars):
+    """When show_choices=False is set, the --help output
+    should print choice metavars instead of values.
+    """
+
+    @click.command()
+    @click.option("-g", type=click.Choice(choices))
+    def cli_with_choices(g):
+        pass
+
+    @click.command()
+    @click.option(
+        "-g",
+        type=click.Choice(choices),
+        show_choices=False,
+    )
+    def cli_without_choices(g):
+        pass
+
+    result = runner.invoke(cli_with_choices, ["--help"])
+    assert f"[{'|'.join([str(i) for i in choices])}]" in result.output
+
+    result = runner.invoke(cli_without_choices, ["--help"])
+    assert metavars in result.output