fix: fix Maybe with future annotations

Fix #4004

Author: bellini666

RELEASE.md

@@ -0,0 +1,3 @@
+Release type: patch
+
+This release fixes the usage of `strawnerry.Maybe` inside modules using `from __future__ import annotations`

poetry.lock

@@ -88,7 +88,6 @@ dev = [
   "pyinstrument (>=4.0.0)",
   "pytest (>=7.2,<8.0)",
   "pytest-asyncio (>=0.20.3)",
-  "pytest-codspeed (>=3.0.0)",
   "pytest-cov (>=4.0.0,<5.0.0)",
   "pytest-emoji (>=0.2.0,<0.3.0)",
   "pytest-mock (>=3.10,<4.0)",

pyproject.toml

@@ -1,3 +1,4 @@
+import re
 import typing
 from typing import TYPE_CHECKING, Any, Generic, TypeAlias, TypeVar, Union
 
@@ -36,7 +37,16 @@ def __bool__(self) -> bool:
     class Maybe(Generic[T]): ...
 
 
+_maybe_re = re.compile(r"^(?:strawberry\.)?Maybe\[(.+)\]$")
+
+
 def _annotation_is_maybe(annotation: Any) -> bool:
+    if isinstance(annotation, str):
+        # Ideally we would try to evaluate the annotation, but the args inside
+        # may still not be available, as the module is still being constructed.
+        # Checking for the pattern should be good enough for now.
+        return _maybe_re.match(annotation) is not None
+
     return (orig := typing.get_origin(annotation)) and orig is Maybe
 
 

strawberry/types/maybe.py

@@ -0,0 +1,68 @@
+from __future__ import annotations
+
+from textwrap import dedent
+
+import strawberry
+from strawberry import Maybe
+
+
+def test_maybe_annotation_from_strawberry():
+    global MyInput
+    try:
+
+        @strawberry.input
+        class MyInput:
+            my_value: strawberry.Maybe[str]
+
+        @strawberry.type
+        class Query:
+            @strawberry.field
+            def test(self, my_input: MyInput) -> str:
+                return "OK"
+
+        schema = strawberry.Schema(query=Query)
+        expected_schema = dedent("""
+        input MyInput {
+          myValue: String
+        }
+
+        type Query {
+          test(myInput: MyInput!): String!
+        }
+        """).strip()
+        assert str(schema) == expected_schema
+
+        assert MyInput()
+    finally:
+        del MyInput
+
+
+def test_maybe_annotation_directly():
+    global MyInput
+    try:
+
+        @strawberry.input
+        class MyInput:
+            my_value: Maybe[str]
+
+        @strawberry.type
+        class Query:
+            @strawberry.field
+            def test(self, my_input: MyInput) -> str:
+                return "OK"
+
+        schema = strawberry.Schema(query=Query)
+        expected_schema = dedent("""
+        input MyInput {
+          myValue: String
+        }
+
+        type Query {
+          test(myInput: MyInput!): String!
+        }
+        """).strip()
+        assert str(schema) == expected_schema
+
+        assert MyInput()
+    finally:
+        del MyInput