From 69719096bda56661a3e64cf301216e2fda6bcf80 Mon Sep 17 00:00:00 2001
From: Jean-Baptiste Braun <jbaptiste.braun@gmail.com>
Date: Fri, 22 May 2026 12:19:33 +0200
Subject: [PATCH 1/2] fix: type CachedResponse.__init__ so mypy --strict
 accepts it (#628)

Without ``-> None`` and parameter annotations, calling
``CachedResponse(response, timeout)`` in a mypy --strict codebase
raises ``[no-untyped-call]``. Annotate the constructor and document
the in-place ``__dict__`` swap that adopts an existing Response.
---
 CHANGES.rst                   |  7 +++++++
 src/flask_caching/__init__.py |  8 ++++++--
 tests/test_init.py            | 37 +++++++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index a832c22e..f439bcd3 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,13 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+- Type ``CachedResponse.__init__`` so it doesn't trigger mypy ``[no-untyped-call]``
+  in strict downstream codebases. :issue:`628`
+
+
 Version 2.4.0
 -------------
 
diff --git a/src/flask_caching/__init__.py b/src/flask_caching/__init__.py
index 77bd7576..c2657412 100644
--- a/src/flask_caching/__init__.py
+++ b/src/flask_caching/__init__.py
@@ -57,9 +57,13 @@ class CachedResponse(Response):
     to override the cache TTL dynamically
     """
 
-    timeout = None
+    timeout: int | None = None
 
-    def __init__(self, response, timeout):
+    def __init__(self, response: Response, timeout: int | None) -> None:
+        # ``CachedResponse`` adopts the state of an existing Response in
+        # place rather than calling ``Response.__init__``; copying
+        # ``__dict__`` preserves headers, status and body without having
+        # to round-trip the response through Werkzeug's constructor.
         self.__dict__ = response.__dict__
         self.timeout = timeout
 
diff --git a/tests/test_init.py b/tests/test_init.py
index f1b2d900..2416d9f7 100644
--- a/tests/test_init.py
+++ b/tests/test_init.py
@@ -1,9 +1,12 @@
 import importlib.util
+import inspect
 
 import pytest
 from flask import Flask
+from flask import make_response
 
 from flask_caching import Cache
+from flask_caching import CachedResponse
 from flask_caching.backends import FileSystemCache
 from flask_caching.backends import MemcachedCache
 from flask_caching.backends import NullCache
@@ -61,3 +64,37 @@ def test_init_nullcache(cache_type, app, tmp_path):
     cache = Cache(app=app)
 
     assert isinstance(app.extensions["cache"][cache], cache_type)
+
+
+def test_cached_response_init_is_typed():
+    """Regression test for issue #628.
+
+    ``CachedResponse.__init__`` must declare a return type and parameter
+    types so that mypy ``--strict`` doesn't flag construction in typed
+    code with ``[no-untyped-call]``. See
+    https://github.com/pallets-eco/flask-caching/issues/628.
+    """
+    sig = inspect.signature(CachedResponse.__init__)
+    # __init__ should declare ``-> None`` rather than be untyped.
+    # inspect.signature returns the literal ``None`` for ``-> None``.
+    assert sig.return_annotation is None, (
+        f"CachedResponse.__init__ return annotation is {sig.return_annotation!r}; "
+        "expected None"
+    )
+    # All non-self parameters should carry an annotation.
+    for name, param in sig.parameters.items():
+        if name == "self":
+            continue
+        assert param.annotation is not inspect.Parameter.empty, (
+            f"CachedResponse.__init__ parameter {name!r} has no annotation"
+        )
+
+
+def test_cached_response_construction_with_flask_response():
+    """Sanity check that CachedResponse still wraps a flask Response."""
+    app = Flask(__name__)
+    with app.test_request_context():
+        resp = make_response("hi")
+        cached = CachedResponse(resp, 10)
+    assert cached.timeout == 10
+    assert cached.get_data(as_text=True) == "hi"

From 80b8a7145cee81a8b031160c7115aa8e123589cf Mon Sep 17 00:00:00 2001
From: "pre-commit-ci-lite[bot]"
 <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Date: Fri, 22 May 2026 10:26:48 +0000
Subject: [PATCH 2/2] [pre-commit.ci lite] apply automatic fixes

---
 tests/test_init.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/test_init.py b/tests/test_init.py
index 2416d9f7..980ea9a2 100644
--- a/tests/test_init.py
+++ b/tests/test_init.py
@@ -85,9 +85,9 @@ def test_cached_response_init_is_typed():
     for name, param in sig.parameters.items():
         if name == "self":
             continue
-        assert param.annotation is not inspect.Parameter.empty, (
-            f"CachedResponse.__init__ parameter {name!r} has no annotation"
-        )
+        assert (
+            param.annotation is not inspect.Parameter.empty
+        ), f"CachedResponse.__init__ parameter {name!r} has no annotation"
 
 
 def test_cached_response_construction_with_flask_response():