fix: Fix repr for Literal types (#29)

* ci(pre-commit.ci): autoupdate

updates:
- [github.com/abravalheri/validate-pyproject: v0.23 → v0.24.1](abravalheri/validate-pyproject@v0.23...v0.24.1)
- [github.com/astral-sh/ruff-pre-commit: v0.9.1 → v0.11.12](astral-sh/ruff-pre-commit@v0.9.1...v0.11.12)
- [github.com/pre-commit/mirrors-mypy: v1.14.1 → v1.16.0](pre-commit/mirrors-mypy@v1.14.1...v1.16.0)

* style(pre-commit.ci): auto fixes [...]

* fix

* fix literal repr

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: tlambert03

src/fieldz/__init__.py

@@ -14,12 +14,14 @@
     "Field",
     "asdict",
     "astuple",
+    "display_as_type",
     "fields",
     "get_adapter",
     "params",
     "replace",
 ]
 
 from ._functions import asdict, astuple, fields, get_adapter, params, replace
+from ._repr import display_as_type
 from ._types import Constraints, DataclassParams, Field
 from .adapters import Adapter

src/fieldz/_repr.py

@@ -35,6 +35,10 @@ def origin_is_union(tp: type[Any] | None) -> bool:
     WithArgsTypes = (typing._GenericAlias, types.GenericAlias, types.UnionType)  # type: ignore[attr-defined]
 
 
+def origin_is_literal(tp: type[Any] | None) -> bool:
+    return tp is typing_extensions.Literal  # type: ignore
+
+
 class PlainRepr(str):
     """String class where repr doesn't include quotes.
 
@@ -67,7 +71,12 @@ def display_as_type(obj: Any, *, modern_union: bool = False) -> str:
     if not isinstance(obj, (typing_base, WithArgsTypes, type)):
         obj = obj.__class__
 
-    if origin_is_union(typing_extensions.get_origin(obj)):
+    origin = typing_extensions.get_origin(obj)
+    if origin_is_literal(origin):
+        # For Literal types, represent the actual values, not their types
+        arg_reprs = [repr(arg) for arg in typing_extensions.get_args(obj)]
+        return f"Literal[{', '.join(arg_reprs)}]"
+    elif origin_is_union(origin):
         args = [display_as_type(x) for x in typing_extensions.get_args(obj)]
         if modern_union:
             return " | ".join(args)

tests/test_repr.py

@@ -1,4 +1,4 @@
-from typing import Any, Generic, Optional, TypeVar, Union
+from typing import Any, Generic, Literal, Optional, TypeVar, Union
 
 from typing_extensions import Annotated
 
@@ -28,6 +28,7 @@ def test_PlainRepr() -> None:
     assert PlainRepr.for_type(Optional[int]) == "Optional[int]"
     assert PlainRepr.for_type(Union[int, str]) == "Union[int, str]"
     assert PlainRepr.for_type(Optional[int], modern_union=True) == "int | None"
+    assert PlainRepr.for_type(Literal[1, "2", (1, 2)]) == "Literal[1, '2', (1, 2)]"
 
     assert PlainRepr.for_type(func) == "func"
     assert PlainRepr.for_type(Foo()) == "Foo"