Fix badly encoded charset exception instead of falling back to detect…

…or (#9160)

CHANGES/9160.bugfix

@@ -0,0 +1 @@
+Fixed badly encoded charset crashing when getting response text instead of falling back to charset detector.

CONTRIBUTORS.txt

@@ -280,6 +280,7 @@ Pawel Kowalski
 Pawel Miech
 Pepe Osca
 Philipp A.
+Pierre-Louis Peeters
 Pieter van Beek
 Qiao Han
 Rafael Viotti

aiohttp/client_reqrep.py

@@ -1090,7 +1090,7 @@ def get_encoding(self) -> str:
 
         encoding = mimetype.parameters.get("charset")
         if encoding:
-            with contextlib.suppress(LookupError):
+            with contextlib.suppress(LookupError, ValueError):
                 return codecs.lookup(encoding).name
 
         if mimetype.type == "application" and (

tests/test_client_response.py

@@ -423,6 +423,38 @@ def side_effect(*args: object, **kwargs: object) -> "asyncio.Future[bytes]":
     assert response._connection is None
 
 
+async def test_text_badly_encoded_encoding_header(
+    loop: asyncio.AbstractEventLoop, session: ClientSession
+) -> None:
+    session._resolve_charset = lambda *_: "utf-8"
+    response = ClientResponse(
+        "get",
+        URL("http://def-cl-resp.org"),
+        request_info=mock.Mock(),
+        writer=WriterMock(),
+        continue100=None,
+        timer=TimerNoop(),
+        traces=[],
+        loop=loop,
+        session=session,
+    )
+
+    def side_effect(*args: object, **kwargs: object) -> "asyncio.Future[bytes]":
+        fut = loop.create_future()
+        fut.set_result(b"foo")
+        return fut
+
+    h = {"Content-Type": "text/html; charset=\udc81gutf-8\udc81\udc8d"}
+    response._headers = CIMultiDictProxy(CIMultiDict(h))
+    content = response.content = mock.Mock()
+    content.read.side_effect = side_effect
+
+    await response.read()
+    encoding = response.get_encoding()
+
+    assert encoding == "utf-8"
+
+
 async def test_text_custom_encoding(
     loop: asyncio.AbstractEventLoop, session: ClientSession
 ) -> None: