🐛 Avoid printing default: None in the help section when using Rich

tests/test_rich_utils.py

@@ -50,3 +50,32 @@ def main() -> None:
 
     assert result.exit_code == 0
     assert "Show this message" in result.stdout
+
+
+def test_rich_doesnt_print_None_default():
+    app = typer.Typer(rich_markup_mode="rich")
+
+    @app.command()
+    def main(
+        name: str,
+        option_1: str = typer.Option(
+            "option_1_default",
+        ),
+        option_2: str = typer.Option(
+            ...,
+        ),
+    ):
+        print(f"Hello {name}")
+        print(f"First: {option_1}")
+        print(f"Second: {option_2}")
+
+    result = runner.invoke(app, ["--help"])
+    assert "Usage" in result.stdout
+    assert "name" in result.stdout
+    assert "option-1" in result.stdout
+    assert "option-2" in result.stdout
+    assert result.stdout.count("[default: None]") == 0
+    result = runner.invoke(app, ["Rick", "--option-2=Morty"])
+    assert "Hello Rick" in result.stdout
+    assert "First: option_1_default" in result.stdout
+    assert "Second: Morty" in result.stdout

typer/rich_utils.py

@@ -288,9 +288,11 @@ def _get_parameter_help(
     # Default value
     # This uses Typer's specific param._get_default_string
     if isinstance(param, (TyperOption, TyperArgument)):
-        if param.show_default:
-            show_default_is_str = isinstance(param.show_default, str)
-            default_value = param._extract_default_help_str(ctx=ctx)
+        default_value = param._extract_default_help_str(ctx=ctx)
+        show_default_is_str = isinstance(param.show_default, str)
+        if show_default_is_str or (
+            default_value is not None and (param.show_default or ctx.show_default)
+        ):
             default_str = param._get_default_string(
                 ctx=ctx,
                 show_default_is_str=show_default_is_str,