fix never run code (#3145)

* fix never run code

* add client session timeout arguments unit test

* add change log

CHANGES/3145.bugfix

@@ -0,0 +1 @@
+Fix timeout precondition checkers

aiohttp/client.py

@@ -146,24 +146,21 @@ def __init__(self, *, connector=None, loop=None, cookies=None,
         self._json_serialize = json_serialize
         if timeout is not sentinel:
             self._timeout = timeout
+            if read_timeout is not sentinel:
+                raise ValueError("read_timeout and timeout parameters "
+                                 "conflict, please setup "
+                                 "timeout.read")
+            if conn_timeout is not None:
+                raise ValueError("conn_timeout and timeout parameters "
+                                 "conflict, please setup "
+                                 "timeout.connect")
         else:
             self._timeout = DEFAULT_TIMEOUT
             if read_timeout is not sentinel:
-                if timeout is not sentinel:
-                    raise ValueError("read_timeout and timeout parameters "
-                                     "conflict, please setup "
-                                     "timeout.read")
-                else:
-                    self._timeout = attr.evolve(self._timeout,
-                                                total=read_timeout)
+                self._timeout = attr.evolve(self._timeout, total=read_timeout)
             if conn_timeout is not None:
-                if timeout is not sentinel:
-                    raise ValueError("conn_timeout and timeout parameters "
-                                     "conflict, please setup "
-                                     "timeout.connect")
-                else:
-                    self._timeout = attr.evolve(self._timeout,
-                                                connect=conn_timeout)
+                self._timeout = attr.evolve(self._timeout,
+                                            connect=conn_timeout)
         self._raise_for_status = raise_for_status
         self._auto_decompress = auto_decompress
         self._trust_env = trust_env

tests/test_client_session.py

@@ -12,7 +12,7 @@
 from yarl import URL
 
 import aiohttp
-from aiohttp import hdrs, web
+from aiohttp import client, hdrs, web
 from aiohttp.client import ClientSession
 from aiohttp.client_reqrep import ClientRequest
 from aiohttp.connector import BaseConnector, TCPConnector
@@ -646,3 +646,22 @@ def test_client_session_custom_attr(loop):
     session = ClientSession(loop=loop)
     with pytest.warns(DeprecationWarning):
         session.custom = None
+
+
+def test_client_session_timeout_args(loop):
+    session1 = ClientSession(loop=loop)
+    assert session1._timeout == client.DEFAULT_TIMEOUT
+
+    session2 = ClientSession(loop=loop, read_timeout=20*60, conn_timeout=30*60)
+    assert session2._timeout == client.ClientTimeout(total=20*60,
+                                                     connect=30*60)
+
+    with pytest.raises(ValueError):
+        ClientSession(loop=loop,
+                      timeout=client.ClientTimeout(total=10*60),
+                      read_timeout=20*60)
+
+    with pytest.raises(ValueError):
+        ClientSession(loop=loop,
+                      timeout=client.ClientTimeout(total=10 * 60),
+                      conn_timeout=30 * 60)