py(deps[dev]) Scope pillow and fastmcp to Python 3.11+

docs/conftest.py

@@ -0,0 +1,14 @@
+"""Conftest.py for the docs tree's doctest collection.
+
+``fastmcp`` is a dev dependency on Python 3.11+ only, so the demo server that
+imports it cannot be collected without it.
+"""
+
+from __future__ import annotations
+
+import importlib.util
+
+collect_ignore: list[str] = []
+
+if importlib.util.find_spec("fastmcp") is None:
+    collect_ignore.append("_ext/fastmcp_demo_server.py")

pyproject.toml

@@ -68,14 +68,14 @@ dev = [
   # which no shim reproduces faithfully — an SDK field rename is invisible
   # to a hand-written stub. Dev-only: the extension keeps working without
   # FastMCP installed, and its real-object tests skip when it is absent.
-  "fastmcp>=4.0.2",
+  "fastmcp>=4.0.2; python_version >= '3.11'",
   "pytest",
   "pytest-asyncio",
   "pytest-rerunfailures",
   "pytest-mock",
   "pytest-watcher",
   "pytest-playwright",
-  "pillow",
+  "pillow>=13; python_version >= '3.11'",
   # Coverage
   "codecov",
   "coverage",
@@ -138,6 +138,20 @@ ignore_errors = true
 module = ["fastmcp", "fastmcp.*"]
 ignore_missing_imports = true
 
+[[tool.mypy.overrides]]
+# pillow and fastmcp (with its pydantic and mcp dependencies) are installed
+# on Python 3.11+ only, so on 3.10 these modules type-check against Any.
+module = ["PIL", "PIL.*", "pydantic", "pydantic.*", "mcp", "mcp.*"]
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = [
+  "tests.ext.fastmcp.test_real_server",
+  "tests.visual.test_visual_regression",
+  "fastmcp_demo_server",
+]
+disable_error_code = ["misc", "no-any-return", "untyped-decorator"]
+
 [tool.ruff]
 target-version = "py310"
 extend-exclude = [

tests/visual/test_visual_regression.py

@@ -22,9 +22,13 @@
 import typing as t
 
 import pytest
-from PIL import Image, ImageChops
 from playwright.sync_api import Page
 
+# Pillow is scoped to Python 3.11+ in the dev group; skip the module without it.
+pytest.importorskip("PIL")
+
+from PIL import Image, ImageChops
+
 _BASELINE_DIR = (
     pathlib.Path(__file__).resolve().parent / "__snapshots__" / "baseline-scss"
 )