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Make deprecation warnings visible and controllable

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This commit is contained in:
Jeremiah Lowin 2025-06-11 10:13:01 -04:00
commit e82cd9f742
11 changed files with 207 additions and 151 deletions
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3
src/fastmcp/__init__.py
View file

@ -25,7 +25,6 @@ __all__ = [
]
# ensure deprecation warnings are displayedby default
if settings.deprecation_warnings:
warnings.simplefilter("default", DeprecationWarning)
else:
warnings.simplefilter("ignore", DeprecationWarning)

12
src/fastmcp/client/transports.py
View file

@ -20,6 +20,7 @@ from mcp.shared.memory import create_client_server_memory_streams
from pydantic import AnyUrl
from typing_extensions import Unpack
import fastmcp
from fastmcp.client.auth.bearer import BearerAuth
from fastmcp.client.auth.oauth import OAuth
from fastmcp.server.dependencies import get_http_headers
@ -109,11 +110,12 @@ class WSTransport(ClientTransport):
def __init__(self, url: str | AnyUrl):
# we never really used this transport, so it can be removed at any time
warnings.warn(
"WSTransport is a deprecated MCP transport and will be removed in a future version. Use StreamableHttpTransport instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"WSTransport is a deprecated MCP transport and will be removed in a future version. Use StreamableHttpTransport instead.",
DeprecationWarning,
stacklevel=2,
)
if isinstance(url, AnyUrl):
url = str(url)
if not isinstance(url, str) or not url.startswith("ws"):

11
src/fastmcp/prompts/prompt_manager.py
View file

@ -60,11 +60,12 @@ class PromptManager:
) -> FunctionPrompt:
"""Create a prompt from a function."""
# deprecated in 2.7.0
warnings.warn(
"PromptManager.add_prompt_from_fn() is deprecated. Use Prompt.from_function() and call add_prompt() instead.",
DeprecationWarning,
stacklevel=2,
)
if settings.deprecation_warnings:
warnings.warn(
"PromptManager.add_prompt_from_fn() is deprecated. Use Prompt.from_function() and call add_prompt() instead.",
DeprecationWarning,
stacklevel=2,
)
prompt = FunctionPrompt.from_function(
fn, name=name, description=description, tags=tags
)

22
src/fastmcp/resources/resource_manager.py
View file

@ -123,11 +123,12 @@ class ResourceManager:
returns the existing resource.
"""
# deprecated in 2.7.0
warnings.warn(
"add_resource_from_fn is deprecated. Use Resource.from_function() and call add_resource() instead.",
DeprecationWarning,
stacklevel=2,
)
if settings.deprecation_warnings:
warnings.warn(
"add_resource_from_fn is deprecated. Use Resource.from_function() and call add_resource() instead.",
DeprecationWarning,
stacklevel=2,
)
resource = Resource.from_function(
fn=fn,
uri=uri,
@ -180,11 +181,12 @@ class ResourceManager:
) -> ResourceTemplate:
"""Create a template from a function."""
# deprecated in 2.7.0
warnings.warn(
"add_template_from_fn is deprecated. Use ResourceTemplate.from_function() and call add_template() instead.",
DeprecationWarning,
stacklevel=2,
)
if settings.deprecation_warnings:
warnings.warn(
"add_template_from_fn is deprecated. Use ResourceTemplate.from_function() and call add_template() instead.",
DeprecationWarning,
stacklevel=2,
)
template = ResourceTemplate.from_function(
fn,
uri_template=uri_template,

18
src/fastmcp/server/context.py
View file

@ -22,6 +22,7 @@ from pydantic.networks import AnyUrl
from starlette.requests import Request
import fastmcp.server.dependencies
from fastmcp import settings
from fastmcp.server.server import FastMCP
from fastmcp.utilities.logging import get_logger
@ -242,14 +243,15 @@ class Context:
def get_http_request(self) -> Request:
"""Get the active starlette request."""
# Deprecation warning, added in FastMCP 2.2.11
warnings.warn(
"Context.get_http_request() is deprecated and will be removed in a future version. "
"Use get_http_request() from fastmcp.server.dependencies instead. "
"See https://gofastmcp.com/patterns/http-requests for more details.",
DeprecationWarning,
stacklevel=2,
)
# Deprecated in 2.2.11
if settings.deprecation_warnings:
warnings.warn(
"Context.get_http_request() is deprecated and will be removed in a future version. "
"Use get_http_request() from fastmcp.server.dependencies instead. "
"See https://gofastmcp.com/patterns/http-requests for more details.",
DeprecationWarning,
stacklevel=2,
)
return fastmcp.server.dependencies.get_http_request()

34
src/fastmcp/server/openapi.py
View file

@ -16,6 +16,7 @@ import httpx
from mcp.types import EmbeddedResource, ImageContent, TextContent, ToolAnnotations
from pydantic.networks import AnyUrl
import fastmcp
from fastmcp.exceptions import ToolError
from fastmcp.resources import Resource, ResourceTemplate
from fastmcp.server.dependencies import get_http_headers
@ -129,27 +130,30 @@ class RouteMap:
"""Validate and process the route map after initialization."""
# Handle backward compatibility for route_type, deprecated in 2.5.0
if self.mcp_type is None and self.route_type is not None:
warnings.warn(
"The 'route_type' parameter is deprecated and will be removed in a future version. "
"Use 'mcp_type' instead with the appropriate MCPType value.",
DeprecationWarning,
stacklevel=2,
)
if isinstance(self.route_type, RouteType):
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The RouteType class is deprecated and will be removed in a future version. "
"Use MCPType instead.",
"The 'route_type' parameter is deprecated and will be removed in a future version. "
"Use 'mcp_type' instead with the appropriate MCPType value.",
DeprecationWarning,
stacklevel=2,
)
if isinstance(self.route_type, RouteType):
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The RouteType class is deprecated and will be removed in a future version. "
"Use MCPType instead.",
DeprecationWarning,
stacklevel=2,
)
# Check for the deprecated IGNORE value
if self.route_type == RouteType.IGNORE:
warnings.warn(
"RouteType.IGNORE is deprecated and will be removed in a future version. "
"Use MCPType.EXCLUDE instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"RouteType.IGNORE is deprecated and will be removed in a future version. "
"Use MCPType.EXCLUDE instead.",
DeprecationWarning,
stacklevel=2,
)
# Convert from RouteType to MCPType if needed
if isinstance(self.route_type, RouteType):

175
src/fastmcp/server/server.py
View file

@ -242,11 +242,12 @@ class FastMCP(Generic[LifespanResultT]):
]:
if arg is not None:
# Deprecated in 2.8.0
warnings.warn(
f"Providing `{name}` when creating a server is deprecated. Provide it when calling `run` or as a global setting instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
f"Providing `{name}` when creating a server is deprecated. Provide it when calling `run` or as a global setting instead.",
DeprecationWarning,
stacklevel=2,
)
deprecated_settings[name] = arg
combined_settings = fastmcp.settings.model_dump() | deprecated_settings
@ -254,11 +255,13 @@ class FastMCP(Generic[LifespanResultT]):
@property
def settings(self) -> Settings:
warnings.warn(
"Accessing `.settings` on a FastMCP instance is deprecated. Use the global `fastmcp.settings` instead.",
DeprecationWarning,
stacklevel=2,
)
# Deprecated in 2.8.0
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"Accessing `.settings` on a FastMCP instance is deprecated. Use the global `fastmcp.settings` instead.",
DeprecationWarning,
stacklevel=2,
)
return self._deprecated_settings
@property
@ -865,11 +868,12 @@ class FastMCP(Generic[LifespanResultT]):
tags: Optional set of tags for categorizing the resource
"""
# deprecated since 2.7.0
warnings.warn(
"The add_resource_fn method is deprecated. Use the resource decorator instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The add_resource_fn method is deprecated. Use the resource decorator instead.",
DeprecationWarning,
stacklevel=2,
)
self._resource_manager.add_resource_or_template_from_fn(
fn=fn,
uri=uri,
@ -1233,13 +1237,14 @@ class FastMCP(Generic[LifespanResultT]):
"""Run the server using SSE transport."""
# Deprecated since 2.3.2
warnings.warn(
"The run_sse_async method is deprecated (as of 2.3.2). Use run_http_async for a "
"modern (non-SSE) alternative, or create an SSE app with "
"`fastmcp.server.http.create_sse_app` and run it directly.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The run_sse_async method is deprecated (as of 2.3.2). Use run_http_async for a "
"modern (non-SSE) alternative, or create an SSE app with "
"`fastmcp.server.http.create_sse_app` and run it directly.",
DeprecationWarning,
stacklevel=2,
)
await self.run_http_async(
transport="sse",
host=host,
@ -1264,12 +1269,13 @@ class FastMCP(Generic[LifespanResultT]):
middleware: A list of middleware to apply to the app
"""
# Deprecated since 2.3.2
warnings.warn(
"The sse_app method is deprecated (as of 2.3.2). Use http_app as a modern (non-SSE) "
"alternative, or call `fastmcp.server.http.create_sse_app` directly.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The sse_app method is deprecated (as of 2.3.2). Use http_app as a modern (non-SSE) "
"alternative, or call `fastmcp.server.http.create_sse_app` directly.",
DeprecationWarning,
stacklevel=2,
)
return create_sse_app(
server=self,
message_path=message_path or self._deprecated_settings.message_path,
@ -1292,11 +1298,12 @@ class FastMCP(Generic[LifespanResultT]):
middleware: A list of middleware to apply to the app
"""
# Deprecated since 2.3.2
warnings.warn(
"The streamable_http_app method is deprecated (as of 2.3.2). Use http_app() instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The streamable_http_app method is deprecated (as of 2.3.2). Use http_app() instead.",
DeprecationWarning,
stacklevel=2,
)
return self.http_app(path=path, middleware=middleware)
def http_app(
@ -1349,12 +1356,13 @@ class FastMCP(Generic[LifespanResultT]):
uvicorn_config: dict[str, Any] | None = None,
) -> None:
# Deprecated since 2.3.2
warnings.warn(
"The run_streamable_http_async method is deprecated (as of 2.3.2). "
"Use run_http_async instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The run_streamable_http_async method is deprecated (as of 2.3.2). "
"Use run_http_async instead.",
DeprecationWarning,
stacklevel=2,
)
await self.run_http_async(
transport="streamable-http",
host=host,
@ -1422,30 +1430,33 @@ class FastMCP(Generic[LifespanResultT]):
if tool_separator is not None:
# Deprecated since 2.4.0
warnings.warn(
"The tool_separator parameter is deprecated and will be removed in a future version. "
"Tools are now prefixed using 'prefix_toolname' format.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The tool_separator parameter is deprecated and will be removed in a future version. "
"Tools are now prefixed using 'prefix_toolname' format.",
DeprecationWarning,
stacklevel=2,
)
if resource_separator is not None:
# Deprecated since 2.4.0
warnings.warn(
"The resource_separator parameter is deprecated and ignored. "
"Resource prefixes are now added using the protocol://prefix/path format.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The resource_separator parameter is deprecated and ignored. "
"Resource prefixes are now added using the protocol://prefix/path format.",
DeprecationWarning,
stacklevel=2,
)
if prompt_separator is not None:
# Deprecated since 2.4.0
warnings.warn(
"The prompt_separator parameter is deprecated and will be removed in a future version. "
"Prompts are now prefixed using 'prefix_promptname' format.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The prompt_separator parameter is deprecated and will be removed in a future version. "
"Prompts are now prefixed using 'prefix_promptname' format.",
DeprecationWarning,
stacklevel=2,
)
# if as_proxy is not specified and the server has a custom lifespan,
# we should treat it as a proxy
@ -1507,30 +1518,33 @@ class FastMCP(Generic[LifespanResultT]):
"""
if tool_separator is not None:
# Deprecated since 2.4.0
warnings.warn(
"The tool_separator parameter is deprecated and will be removed in a future version. "
"Tools are now prefixed using 'prefix_toolname' format.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The tool_separator parameter is deprecated and will be removed in a future version. "
"Tools are now prefixed using 'prefix_toolname' format.",
DeprecationWarning,
stacklevel=2,
)
if resource_separator is not None:
# Deprecated since 2.4.0
warnings.warn(
"The resource_separator parameter is deprecated and ignored. "
"Resource prefixes are now added using the protocol://prefix/path format.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The resource_separator parameter is deprecated and ignored. "
"Resource prefixes are now added using the protocol://prefix/path format.",
DeprecationWarning,
stacklevel=2,
)
if prompt_separator is not None:
# Deprecated since 2.4.0
warnings.warn(
"The prompt_separator parameter is deprecated and will be removed in a future version. "
"Prompts are now prefixed using 'prefix_promptname' format.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"The prompt_separator parameter is deprecated and will be removed in a future version. "
"Prompts are now prefixed using 'prefix_promptname' format.",
DeprecationWarning,
stacklevel=2,
)
# Import tools from the mounted server
tool_prefix = f"{prefix}_"
@ -1666,11 +1680,12 @@ class FastMCP(Generic[LifespanResultT]):
Create a FastMCP proxy server from a FastMCP client.
"""
# Deprecated since 2.3.5
warnings.warn(
"FastMCP.from_client() is deprecated; use FastMCP.as_proxy() instead.",
DeprecationWarning,
stacklevel=2,
)
if fastmcp.settings.deprecation_warnings:
warnings.warn(
"FastMCP.from_client() is deprecated; use FastMCP.as_proxy() instead.",
DeprecationWarning,
stacklevel=2,
)
return cls.as_proxy(client, **settings)

13
src/fastmcp/settings.py
View file

@ -1,7 +1,6 @@
from __future__ import annotations as _annotations
import inspect
import warnings
from pathlib import Path
from typing import Annotated, Any, Literal
@ -15,6 +14,10 @@ from pydantic_settings import (
)
from typing_extensions import Self
from fastmcp.utilities.logging import get_logger
logger = get_logger(__name__)
LOG_LEVEL = Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"]
DuplicateBehavior = Literal["warn", "error", "replace", "ignore"]
@ -39,10 +42,8 @@ class ExtendedEnvSettingsSource(EnvSettingsSource):
if env_val is not None:
if prefix == "FASTMCP_SERVER_":
# Deprecated in 2.8.0
warnings.warn(
logger.warning(
"Using `FASTMCP_SERVER_` environment variables is deprecated. Use `FASTMCP_` instead.",
DeprecationWarning,
stacklevel=2,
)
return env_val, field_key, value_is_complex
@ -89,10 +90,8 @@ class Settings(BaseSettings):
which accessed fastmcp.settings.settings
"""
# Deprecated in 2.8.0
warnings.warn(
logger.warning(
"Using fastmcp.settings.settings is deprecated. Use fastmcp.settings instead.",
DeprecationWarning,
stacklevel=2,
)
return self

11
src/fastmcp/tools/tool_manager.py
View file

@ -71,11 +71,12 @@ class ToolManager:
) -> Tool:
"""Add a tool to the server."""
# deprecated in 2.7.0
warnings.warn(
"ToolManager.add_tool_from_fn() is deprecated. Use Tool.from_function() and call add_tool() instead.",
DeprecationWarning,
stacklevel=2,
)
if settings.deprecation_warnings:
warnings.warn(
"ToolManager.add_tool_from_fn() is deprecated. Use Tool.from_function() and call add_tool() instead.",
DeprecationWarning,
stacklevel=2,
)
tool = Tool.from_function(
fn,
name=name,

23
tests/deprecated/test_deprecated.py
View file

@ -5,11 +5,34 @@ import pytest
from starlette.applications import Starlette
from fastmcp import Client, FastMCP
from fastmcp.utilities.tests import temporary_settings
# reset deprecation warnings for this module
pytestmark = pytest.mark.filterwarnings("default::DeprecationWarning")
class TestDeprecationWarningsSetting:
def test_deprecation_warnings_setting_true(self):
with temporary_settings(deprecation_warnings=True):
with pytest.warns(DeprecationWarning) as recorded_warnings:
# will warn once for providing deprecated arg
mcp = FastMCP(host="1.2.3.4")
# will warn once for accessing deprecated property
mcp.settings
assert len(recorded_warnings) == 2
def test_deprecation_warnings_setting_false(self):
with temporary_settings(deprecation_warnings=False):
# will error if a warning is raised
with warnings.catch_warnings():
warnings.simplefilter("error")
# will warn once for providing deprecated arg
mcp = FastMCP(host="1.2.3.4")
# will warn once for accessing deprecated property
mcp.settings
def test_sse_app_deprecation_warning():
"""Test that sse_app raises a deprecation warning."""
server = FastMCP("TestServer")

36
tests/deprecated/test_settings.py
View file

@ -305,7 +305,7 @@ class TestDeprecatedServerInitKwargs:
class TestDeprecatedEnvironmentVariables:
"""Test deprecated environment variable prefixes."""
def test_fastmcp_server_env_var_deprecation_warning(self):
def test_fastmcp_server_env_var_deprecation_warning(self, caplog):
"""Test that FASTMCP_SERVER_ environment variables emit deprecation warnings."""
env_var_name = "FASTMCP_SERVER_HOST"
original_value = os.environ.get(env_var_name)
@ -313,11 +313,15 @@ class TestDeprecatedEnvironmentVariables:
try:
os.environ[env_var_name] = "192.168.1.1"
with pytest.warns(
DeprecationWarning,
match=r"Using `FASTMCP_SERVER_` environment variables is deprecated\. Use `FASTMCP_` instead\.",
):
settings = Settings()
settings = Settings()
# Check that a warning was logged
assert any(
"Using `FASTMCP_SERVER_` environment variables is deprecated. Use `FASTMCP_` instead."
in record.message
for record in caplog.records
if record.levelname == "WARNING"
)
# Verify the setting is still applied
assert settings.host == "192.168.1.1"
@ -333,16 +337,20 @@ class TestDeprecatedEnvironmentVariables:
class TestDeprecatedSettingsProperty:
"""Test deprecated settings property access."""
def test_settings_property_deprecation_warning(self):
"""Test that accessing fastmcp.settings.settings raises a deprecation warning."""
def test_settings_property_deprecation_warning(self, caplog):
"""Test that accessing fastmcp.settings.settings logs a deprecation warning."""
from fastmcp import settings
with pytest.warns(
DeprecationWarning,
match=r"Using fastmcp\.settings\.settings is deprecated\. Use fastmcp\.settings instead\.",
):
# Access the deprecated property
deprecated_settings = settings.settings
# Access the deprecated property
deprecated_settings = settings.settings
# Check that a warning was logged
assert any(
"Using fastmcp.settings.settings is deprecated. Use fastmcp.settings instead."
in record.message
for record in caplog.records
if record.levelname == "WARNING"
)
# Verify it still returns the same settings object
assert deprecated_settings is settings