databind.json/: fix: Evaluate forward references when creating schema for NamedTuples (#50)

* databind.json/: fix: Evaluate forward references when creating schema for NamedTuples

* Updated PR references in 1 changelogs.

skip-checks: true

---------

Co-authored-by: GitHub Action <[email protected]>

Author: NiklasRosenstein

databind.json/.changelog/_unreleased.toml

@@ -0,0 +1,6 @@
+[[entries]]
+id = "eee787ce-d9d3-442e-acee-b274edc72176"
+type = "fix"
+description = "Evaluate forward references when creating schema for NamedTuples"
+author = "@NiklasRosenstein"
+pr = "https://github.com/NiklasRosenstein/python-databind/pull/50"

databind.json/src/databind/json/converters.py

@@ -97,7 +97,9 @@ def convert(self, ctx: Context) -> t.Any:
             schema = Schema(
                 fields={
                     name: Field(
-                        datatype=TypeHint(type_),
+                        # We need to evaluate the type hint to remove forward references. The source is needed to
+                        # understand the context in which forward references must be evaluated.
+                        datatype=TypeHint(type_, source=datatype.type).evaluate(),
                     )
                     for name, type_ in getattr(datatype.type, "__annotations__").items()
                 },

databind.json/src/databind/json/tests/converters_test.py

@@ -539,7 +539,7 @@ def test__typing_NamedTuple() -> None:
 
     class Nt(t.NamedTuple):
         a: int
-        b: str
+        b: "str"
 
     assert mapper.serialize(Nt(1, "2"), Nt) == {"a": 1, "b": "2"}
     assert mapper.deserialize({"a": 1, "b": "2"}, Nt) == Nt(1, "2")