Fix exact imports for reused tree-scope models (#3042)

Author: koxudaxi

src/datamodel_code_generator/parser/base.py

@@ -1779,6 +1779,7 @@ def __reuse_model(self, models: list[DataModel], require_update_action_models: l
                     duplicates.append(model)
                 else:
                     inherited_model = model.create_reuse_model(cached_model_reference)
+                    model.replace_children_in_models(models, inherited_model.reference)
                     if cached_model_reference.path in require_update_action_models:
                         add_model_path_to_list(require_update_action_models, inherited_model)
                     self._replace_model_in_list(models, model, inherited_model)
@@ -1875,6 +1876,7 @@ def __create_shared_module_from_duplicates(  # noqa: PLR0912
                     models_to_remove[module].add(duplicate_model)
                 else:
                     inherited_model = duplicate_model.create_reuse_model(shared_ref)
+                    duplicate_model.replace_children_in_models(models, inherited_model.reference)
                     if shared_ref.path in require_update_action_models:
                         add_model_path_to_list(require_update_action_models, inherited_model)
                     self._replace_model_in_list(models, duplicate_model, inherited_model)

tests/data/expected/main/jsonschema/reuse_scope_tree_exact_imports/__init__.py

@@ -0,0 +1,2 @@
+# generated by datamodel-codegen:
+#   filename:  reuse_scope_tree

tests/data/expected/main/jsonschema/reuse_scope_tree_exact_imports/schema_a.py

@@ -0,0 +1,16 @@
+# generated by datamodel-codegen:
+#   filename:  reuse_scope_tree
+
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+from .shared import SharedModel as SharedModel_1
+
+
+class SharedModel(SharedModel_1):
+    pass
+
+
+class Model(BaseModel):
+    data: SharedModel | None = None

tests/data/expected/main/jsonschema/reuse_scope_tree_exact_imports/schema_b.py

@@ -0,0 +1,12 @@
+# generated by datamodel-codegen:
+#   filename:  schema_b.json
+
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+from .shared import SharedModel
+
+
+class Model(BaseModel):
+    info: SharedModel | None = None

tests/data/expected/main/jsonschema/reuse_scope_tree_exact_imports/shared.py

@@ -0,0 +1,11 @@
+# generated by datamodel-codegen:
+#   filename:  shared.py
+
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+
+class SharedModel(BaseModel):
+    id: int | None = None
+    name: str | None = None

tests/main/jsonschema/test_main_jsonschema.py

@@ -5711,6 +5711,25 @@ def test_main_jsonschema_reuse_scope_tree(output_dir: Path) -> None:
     )
 
 
+def test_main_jsonschema_reuse_scope_tree_exact_imports(output_dir: Path) -> None:
+    """Test --reuse-scope=tree with --use-exact-imports keeps local subclass references."""
+    run_main_and_assert(
+        input_path=JSON_SCHEMA_DATA_PATH / "reuse_scope_tree",
+        output_path=output_dir,
+        expected_directory=EXPECTED_JSON_SCHEMA_PATH / "reuse_scope_tree_exact_imports",
+        input_file_type="jsonschema",
+        extra_args=[
+            "--output-model-type",
+            "pydantic_v2.BaseModel",
+            "--reuse-model",
+            "--reuse-scope",
+            "tree",
+            "--use-exact-imports",
+            "--disable-timestamp",
+        ],
+    )
+
+
 def test_main_jsonschema_reuse_scope_tree_enum(output_dir: Path) -> None:
     """Test --reuse-scope=tree to deduplicate enum models across multiple files."""
     run_main_and_assert(