From a2904fe33b0dc8c3c3804fa533e1324eaf60e6cc Mon Sep 17 00:00:00 2001
From: Matt Gilson <mgilson@lat.ai>
Date: Wed, 23 Aug 2023 16:11:53 -0400
Subject: [PATCH] Handle UNSET values in the strawberry schema.

The codegen currently chokes on `strawberry.UNSET` default values.  This PR updates the codegen to stop raising an exception and instead pass a `GraphQLNullValue(value=UNSET)` to the plugins.  The default python plugin writes a `None` as the default value because there really isn't a well understood concept of UNSET in the python eco
system.  User defined plugins have all the information that they need to handle this differently if they choose to do so.
---
 strawberry/codegen/plugins/python.py            | 3 +++
 strawberry/codegen/query_codegen.py             | 6 ++++--
 strawberry/codegen/types.py                     | 3 ++-
 tests/codegen/conftest.py                       | 1 +
 tests/codegen/snapshots/python/variables.py     | 1 +
 tests/codegen/snapshots/typescript/variables.ts | 1 +
 6 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/strawberry/codegen/plugins/python.py b/strawberry/codegen/plugins/python.py
index 3ad598b857..41b17d4543 100644
--- a/strawberry/codegen/plugins/python.py
+++ b/strawberry/codegen/plugins/python.py
@@ -10,6 +10,7 @@
     GraphQLEnum,
     GraphQLEnumValue,
     GraphQLList,
+    GraphQLNullValue,
     GraphQLObjectType,
     GraphQLOptional,
     GraphQLScalar,
@@ -141,6 +142,8 @@ def _print_argument_value(self, argval: GraphQLArgumentValue) -> str:
                     "GraphQLEnumValue must have a type for python code gen. {argval}"
                 )
             return f"{argval.enum_type}.{argval.name}"
+        if isinstance(argval, GraphQLNullValue):
+            return "None"
         if not hasattr(argval, "value"):
             raise TypeError(f"Unrecognized values type: {argval}")
         return repr(argval.value)
diff --git a/strawberry/codegen/query_codegen.py b/strawberry/codegen/query_codegen.py
index 7b9df2b756..a3628324d2 100644
--- a/strawberry/codegen/query_codegen.py
+++ b/strawberry/codegen/query_codegen.py
@@ -52,6 +52,7 @@
 )
 from strawberry.types.types import StrawberryObjectDefinition
 from strawberry.union import StrawberryUnion
+from strawberry.unset import UNSET
 from strawberry.utils.str_converters import capitalize_first, to_camel_case
 
 from .exceptions import (
@@ -178,8 +179,9 @@ def _get_deps(t: GraphQLType) -> Iterable[GraphQLType]:
 
 def _py_to_graphql_value(obj: Any) -> GraphQLArgumentValue:
     """Convert a python object to a GraphQLArgumentValue."""
-    if obj is None:
-        return GraphQLNullValue()
+    if obj is None or obj is UNSET:
+        return GraphQLNullValue(value=obj)
+
     obj_type = type(obj)
     if obj_type in _TYPE_TO_GRAPHQL_TYPE:
         return _TYPE_TO_GRAPHQL_TYPE[obj_type](obj)
diff --git a/strawberry/codegen/types.py b/strawberry/codegen/types.py
index 37fbec7f66..ac58f5368b 100644
--- a/strawberry/codegen/types.py
+++ b/strawberry/codegen/types.py
@@ -6,6 +6,7 @@
 if TYPE_CHECKING:
     from enum import EnumMeta
     from typing_extensions import Literal
+    from strawberry.unset import UnsetType
 
 
 @dataclass
@@ -134,7 +135,7 @@ class GraphQLBoolValue:
 class GraphQLNullValue:
     """A class that represents a GraphQLNull value."""
 
-    value: None = None
+    value: None | UnsetType = None
 
 
 @dataclass
diff --git a/tests/codegen/conftest.py b/tests/codegen/conftest.py
index 624f57016a..977d761fc9 100644
--- a/tests/codegen/conftest.py
+++ b/tests/codegen/conftest.py
@@ -60,6 +60,7 @@ class Image(Node):
 @strawberry.input
 class PersonInput:
     name: str
+    age: Optional[int] = strawberry.UNSET
 
 
 @strawberry.input
diff --git a/tests/codegen/snapshots/python/variables.py b/tests/codegen/snapshots/python/variables.py
index 0bf72745aa..a19d010717 100644
--- a/tests/codegen/snapshots/python/variables.py
+++ b/tests/codegen/snapshots/python/variables.py
@@ -5,6 +5,7 @@ class OperationNameResult:
 
 class PersonInput:
     name: str
+    age: Optional[int] = None
 
 class ExampleInput:
     id: str
diff --git a/tests/codegen/snapshots/typescript/variables.ts b/tests/codegen/snapshots/typescript/variables.ts
index cf1df65308..88a3d04d21 100644
--- a/tests/codegen/snapshots/typescript/variables.ts
+++ b/tests/codegen/snapshots/typescript/variables.ts
@@ -4,6 +4,7 @@ type OperationNameResult = {
 
 type PersonInput = {
     name: string
+    age: number | undefined
 }
 
 type ExampleInput = {