fix: Always merge multiple GraphQL schemas before parsing (#2873)

* initial idea

* fix test case

* Remove unused imports

---------

Co-authored-by: Koudai Aono <koxudaxi@gmail.com>

Author: siminn-arnorgj

src/datamodel_code_generator/parser/graphql.py

@@ -6,12 +6,10 @@
 
 from __future__ import annotations
 
-from pathlib import Path
 from typing import (
     TYPE_CHECKING,
     Any,
 )
-from urllib.parse import ParseResult
 
 from typing_extensions import Unpack
 
@@ -26,7 +24,6 @@
 from datamodel_code_generator.parser.base import (
     DataType,
     Parser,
-    Source,
     escape_characters,
 )
 from datamodel_code_generator.reference import ModelType, Reference
@@ -40,7 +37,8 @@
 
 
 if TYPE_CHECKING:
-    from collections.abc import Iterator
+    from pathlib import Path
+    from urllib.parse import ParseResult
 
     from datamodel_code_generator._types import GraphQLParserConfigDict
     from datamodel_code_generator.config import GraphQLParserConfig
@@ -137,31 +135,6 @@ def __init__(
         self.use_standard_collections = use_standard_collections
         self.use_union_operator = use_union_operator
 
-    def _get_context_source_path_parts(self) -> Iterator[tuple[Source, list[str]]]:
-        # TODO (denisart): Temporarily this method duplicates
-        # the method `datamodel_code_generator.parser.jsonschema.JsonSchemaParser._get_context_source_path_parts`.
-
-        if isinstance(self.source, list) or (  # pragma: no cover
-            isinstance(self.source, Path) and self.source.is_dir()
-        ):  # pragma: no cover
-            self.current_source_path = Path()
-            self.model_resolver.after_load_files = {
-                self.base_path.joinpath(s.path).resolve().as_posix() for s in self.iter_source
-            }
-
-        for source in self.iter_source:
-            if isinstance(self.source, ParseResult):  # pragma: no cover
-                path_parts = self.get_url_path_parts(self.source)
-            else:
-                path_parts = list(source.path.parts)
-            if self.current_source_path is not None:  # pragma: no cover
-                self.current_source_path = source.path
-            with (
-                self.model_resolver.current_base_path_context(source.path.parent),
-                self.model_resolver.current_root_context(path_parts),
-            ):
-                yield source, path_parts
-
     def _resolve_types(self, paths: list[str], schema: graphql.GraphQLSchema) -> None:
         for type_name, type_ in schema.type_map.items():
             if type_name.startswith("__"):
@@ -523,13 +496,13 @@ def parse_raw(self) -> None:
             graphql.type.introspection.TypeKind.UNION: self.parse_union,
         }
 
-        for source, path_parts in self._get_context_source_path_parts():
-            schema: graphql.GraphQLSchema = build_graphql_schema(source.text)
-            self.raw_obj = schema
+        combined_schema = "\n".join(source.text for source in self.iter_source)
+        schema: graphql.GraphQLSchema = build_graphql_schema(combined_schema)
+        self.raw_obj = schema
 
-            self._resolve_types(path_parts, schema)
+        self._resolve_types([], schema)
 
-            for next_type in self.parse_order:
-                for obj in self.support_graphql_types[next_type]:
-                    parser_ = mapper_from_graphql_type_to_parser_method[next_type]
-                    parser_(obj)
+        for next_type in self.parse_order:
+            for obj in self.support_graphql_types[next_type]:
+                parser_ = mapper_from_graphql_type_to_parser_method[next_type]
+                parser_(obj)

tests/data/expected/main/graphql/split_graphql_schemas.py

@@ -0,0 +1,46 @@
+# generated by datamodel-codegen:
+#   filename:  split
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Literal, TypeAlias
+
+from pydantic import BaseModel, Field
+
+Boolean: TypeAlias = bool
+"""
+The `Boolean` scalar type represents `true` or `false`.
+"""
+
+
+Int: TypeAlias = int
+"""
+The `Int` scalar type represents non-fractional signed whole numeric values. Int can represent values between -(2^31) and 2^31 - 1.
+"""
+
+
+String: TypeAlias = str
+"""
+The `String` scalar type represents textual data, represented as UTF-8 character sequences. The String type is most often used by GraphQL to represent free-form human-readable text.
+"""
+
+
+class Baz(BaseModel):
+    quux: Int
+    typename__: Literal['Baz'] | None = Field('Baz', alias='__typename')
+
+
+class Bar(BaseModel):
+    eggs: String
+    foo: Foo
+    typename__: Literal['Bar'] | None = Field('Bar', alias='__typename')
+
+
+class Foo(BaseModel):
+    baz: Bar
+    id: Int
+    typename__: Literal['Foo'] | None = Field('Foo', alias='__typename')
+
+
+Bar.update_forward_refs()

tests/data/graphql/split/a.graphql

@@ -0,0 +1,7 @@
+type Foo {
+  id: Int!
+}
+
+extend type Bar {
+  eggs: String!
+}

tests/data/graphql/split/b.graphql

@@ -0,0 +1,4 @@
+type Bar {
+  foo: Foo!
+}
+

tests/data/graphql/split/c.graphql

@@ -0,0 +1,7 @@
+extend type Foo {
+  baz: Bar!
+}
+
+type Baz {
+  quux: Int!
+}

tests/main/graphql/test_main_graphql.py

@@ -772,3 +772,14 @@ def test_main_graphql_union_snake_case_field(output_file: Path) -> None:
         expected_file="union_snake_case_field.py",
         extra_args=["--snake-case-field", "--output-model-type", "pydantic_v2.BaseModel"],
     )
+
+
+def test_main_graphql_split_graphql_schemas(output_file: Path) -> None:
+    """Test GraphQL code generation with multiple schema files in a directory."""
+    run_main_and_assert(
+        input_path=GRAPHQL_DATA_PATH / "split",
+        output_path=output_file,
+        input_file_type="graphql",
+        assert_func=assert_file_content,
+        expected_file="split_graphql_schemas.py",
+    )