Merge pull request #180 from modelcontextprotocol/jeremy/relax-pydantic

Relax pydantic, pydantic-settings, and uvicorn requirements

Author: jerome3o-anthropic

pyproject.toml

@@ -25,11 +25,11 @@ dependencies = [
     "anyio>=4.5",
     "httpx>=0.27",
     "httpx-sse>=0.4",
-    "pydantic>=2.10.1,<3.0.0",
+    "pydantic>=2.7.2,<3.0.0",
     "starlette>=0.27",
     "sse-starlette>=1.6.1",
-    "pydantic-settings>=2.6.1",
-    "uvicorn>=0.30",
+    "pydantic-settings>=2.5.2",
+    "uvicorn>=0.23.1",
 ]
 
 [project.optional-dependencies]

tests/server/fastmcp/test_func_metadata.py

@@ -235,8 +235,45 @@ async def check_call(args):
 
 
 def test_complex_function_json_schema():
+    """Test JSON schema generation for complex function arguments.
+    
+    Note: Different versions of pydantic output slightly different
+    JSON Schema formats for model fields with defaults. The format changed in 2.9.0:
+
+    1. Before 2.9.0:
+       {
+         "allOf": [{"$ref": "#/$defs/Model"}],
+         "default": {}
+       }
+       
+    2. Since 2.9.0:
+       {
+         "$ref": "#/$defs/Model",
+         "default": {}
+       }
+       
+    Both formats are valid and functionally equivalent. This test accepts either format
+    to ensure compatibility across our supported pydantic versions.
+    
+    This change in format does not affect runtime behavior since:
+    1. Both schemas validate the same way
+    2. The actual model classes and validation logic are unchanged
+    3. func_metadata uses model_validate/model_dump, not the schema directly
+    """
     meta = func_metadata(complex_arguments_fn)
-    assert meta.arg_model.model_json_schema() == {
+    actual_schema = meta.arg_model.model_json_schema()
+    
+    # Create a copy of the actual schema to normalize
+    normalized_schema = actual_schema.copy()
+    
+    # Normalize the my_model_a_with_default field to handle both pydantic formats
+    if 'allOf' in actual_schema['properties']['my_model_a_with_default']:
+        normalized_schema['properties']['my_model_a_with_default'] = {
+            '$ref': '#/$defs/SomeInputModelA',
+            'default': {}
+        }
+    
+    assert normalized_schema == {
         "$defs": {
             "InnerModel": {
                 "properties": {"x": {"title": "X", "type": "integer"}},