Added EnumChoice completion regression test

Mark pallets/click#3471 as fixed upstream

Author: kdeldycke

docs/benchmark.md

@@ -88,7 +88,7 @@ Click's built-in completion covers command and option names but has several know
 
 **Fish multiline help** ([pallets/click#3043](https://github.com/pallets/click/issues/3043)): help text containing newlines used to break fish completion. **Fixed upstream** in [pallets/click#3126](https://github.com/pallets/click/pull/3126) (merged 2026-04-29), which also closes the bug report. Once click-extra's Click floor bumps to the release that ships the fix, fish completion handles multi-line help text out of the box and no click-extra workaround is needed.
 
-**Enum Choice mismatch** ([pallets/click#3015](https://github.com/pallets/click/issues/3015)): `click.Choice(MyEnum)` completes `MyEnum.foo` instead of `foo` because completion skips the normalization the `Choice` type applies at parse time.
+**Enum Choice mismatch** ([pallets/click#3015](https://github.com/pallets/click/issues/3015)): `click.Choice(MyEnum)` completed `MyEnum.foo` instead of `foo` because completion skipped the normalization the `Choice` type applies at parse time. **Fixed upstream** in [pallets/click#3471](https://github.com/pallets/click/pull/3471) (merged 2026-05-19, first released in Click `8.4.1`), which routes completion through `Choice.normalize_choice()` so suggestions match what the parser accepts. click-extra's lock already resolves to Click `8.4.1`; once its floor rises from `8.3.1` to `>=8.4.1` the gap closes for every supported Click version. click-extra's own [`EnumChoice`](types.md#enumchoice) was never affected: it stores choice strings rather than `Enum` members, so its completions never carried the `Enum.member` form.
 
 **Additional shells rejected upstream** ([pallets/click#2888](https://github.com/pallets/click/issues/2888), [pallets/click#3188](https://github.com/pallets/click/issues/3188), [pallets/click#2672](https://github.com/pallets/click/issues/2672)): Click explicitly rejected adding nushell, Carapace, and PowerShell completion to core: all three issues are closed as `not_planned`, so the door is closed upstream and remains a click-extra opportunity. click-extra could provide `NushellComplete` and `PowerShellComplete` classes, and generate Carapace YAML from its parameter introspection.
 

tests/test_types.py

@@ -566,6 +566,54 @@ def test_enum_choice_case_sensitivity(case_sensitive: bool) -> None:
         )
 
 
+@pytest.mark.parametrize(
+    "source, expected",
+    (
+        (ChoiceSource.KEY, ("first_value", "second_value")),
+        (ChoiceSource.VALUE, ("first-value", "second-value")),
+        (ChoiceSource.STR, ("my-first-value", "my-second-value")),
+    ),
+)
+def test_enum_choice_shell_complete(
+    source: ChoiceSource,
+    expected: tuple[str, str],
+) -> None:
+    """Completion offers normalized choice strings, never the ``Enum.member`` form.
+
+    Regression guard for pallets/click#3015, fixed upstream in pallets/click#3471:
+    completion routes through ``Choice.normalize_choice()``, so an ``EnumChoice``
+    suggests parseable strings (case-folded, as it is case-insensitive by default)
+    instead of ``MyEnum.FIRST_VALUE``.
+    """
+    enum_choice = EnumChoice(MyEnum, choice_source=source)
+
+    # A bare Context/Parameter is enough to drive completion.
+    cli = click.Command("cli", params=[click.Option(["--fmt"], type=enum_choice)])
+    ctx = click.Context(cli)
+    param = cli.params[0]
+
+    def complete(incomplete: str) -> list[str]:
+        items = enum_choice.shell_complete(ctx, param, incomplete)
+        return [item.value for item in items]
+
+    all_choices = complete("")
+
+    # Empty input lists every normalized choice, in declaration order.
+    assert all_choices == list(expected)
+
+    # No suggestion leaks the ``Enum.member`` representation.
+    assert not any("MyEnum" in choice for choice in all_choices)
+
+    # Every suggestion parses back to its member.
+    for choice in all_choices:
+        assert isinstance(enum_choice.convert(choice, param, ctx), MyEnum)
+
+    # Prefix filtering stays case-insensitive.
+    second = expected[1]
+    assert complete(second) == [second]
+    assert complete(second.upper()) == [second]
+
+
 def test_enum_choice_duplicate_string() -> None:
     class BadEnum(StrEnum):
         FIRST = auto()