Set readPending to false when EOF is detected while issue an read

Motivation:

We need to set readPending to false when we detect a EOF while issue a read as otherwise we may not unregister from the Selector / Epoll / KQueue and so keep on receving wakeups.

The important bit is that we may even get a wakeup for a read event but will still will only be able to read 0 bytes from the socket, so we need to be very careful when we clear the readPending. This can happen because we generally using edge-triggered mode for our native transports and because of the nature of edge-triggered we may schedule an read event just to find out there is nothing left to read atm (because we completely drained the socket on the previous read).

Modifications:

Set readPending to false when EOF is detected.

Result:

Fixes [#7255].

transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollStreamChannel.java

@@ -790,6 +790,10 @@ public abstract class AbstractEpollStreamChannel extends AbstractEpollChannel im
                         byteBuf.release();
                         byteBuf = null;
                         close = allocHandle.lastBytesRead() < 0;
+                        if (close) {
+                            // There is nothing left to read as we received an EOF.
+                            readPending = false;
+                        }
                         break;
                     }
                     allocHandle.incMessagesRead(1);

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueStreamChannel.java

@@ -532,6 +532,10 @@ public abstract class AbstractKQueueStreamChannel extends AbstractKQueueChannel
                         byteBuf.release();
                         byteBuf = null;
                         close = allocHandle.lastBytesRead() < 0;
+                        if (close) {
+                            // There is nothing left to read as we received an EOF.
+                            readPending = false;
+                        }
                         break;
                     }
                     allocHandle.incMessagesRead(1);

transport/src/main/java/io/netty/channel/nio/AbstractNioByteChannel.java

@@ -126,6 +126,10 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
                         byteBuf.release();
                         byteBuf = null;
                         close = allocHandle.lastBytesRead() < 0;
+                        if (close) {
+                            // There is nothing left to read as we received an EOF.
+                            readPending = false;
+                        }
                         break;
                     }
 

transport/src/main/java/io/netty/channel/oio/AbstractOioByteChannel.java

@@ -123,6 +123,10 @@ public abstract class AbstractOioByteChannel extends AbstractOioChannel {
                         byteBuf.release();
                         byteBuf = null;
                         close = allocHandle.lastBytesRead() < 0;
+                        if (close) {
+                            // There is nothing left to read as we received an EOF.
+                            readPending = false;
+                        }
                     }
                     break;
                 } else {