Merge branch 'async_callback_issue_0412' of https://github.com/l04m33/Nim into l04m33-async_callback_issue_0412-2

Conflicts:
	lib/pure/asyncdispatch.nim

tests/async/tasyncconnect.nim

@@ -0,0 +1,33 @@
+discard """
+  file: "tasyncconnect.nim"
+  exitcode: 1
+  outputsub: "Error: unhandled exception: Connection refused [Exception]"
+"""
+
+import
+    asyncdispatch,
+    posix
+
+
+const
+    testHost = "127.0.0.1"
+    testPort = Port(17357)
+
+
+when defined(windows) or defined(nimdoc):
+    discard
+else:
+    proc testAsyncConnect() {.async.} =
+        var s = newAsyncRawSocket()
+
+        await s.connect(testHost, testPort)
+
+        var peerAddr: SockAddr
+        var addrSize = Socklen(sizeof(peerAddr))
+        var ret = SocketHandle(s).getpeername(addr(peerAddr), addr(addrSize))
+
+        if ret < 0:
+            echo("`connect(...)` failed but no exception was raised.")
+            quit(2)
+
+    waitFor(testAsyncConnect())

tests/async/tasynceverror.nim

@@ -0,0 +1,65 @@
+discard """
+  file: "tasynceverror.nim"
+  exitcode: 1
+  outputsub: "Error: unhandled exception: Connection reset by peer [Exception]"
+"""
+
+import
+    asyncdispatch,
+    asyncnet,
+    rawsockets,
+    os
+
+
+const
+    testHost = "127.0.0.1"
+    testPort = Port(17357)
+
+
+when defined(windows) or defined(nimdoc):
+    discard
+else:
+    proc createListenSocket(host: string, port: Port): TAsyncFD =
+        result = newAsyncRawSocket()
+
+        SocketHandle(result).setSockOptInt(SOL_SOCKET, SO_REUSEADDR, 1)
+
+        var aiList = getAddrInfo(host, port, AF_INET)
+        if SocketHandle(result).bindAddr(aiList.ai_addr, aiList.ai_addrlen.Socklen) < 0'i32:
+          dealloc(aiList)
+          raiseOSError(osLastError())
+        dealloc(aiList)
+
+        if SocketHandle(result).listen(1) < 0'i32:
+            raiseOSError(osLastError())
+
+
+    proc testAsyncSend() {.async.} =
+        var
+            ls = createListenSocket(testHost, testPort)
+            s = newAsyncSocket()
+
+        await s.connect(testHost, testPort)
+        
+        var ps = await ls.accept()
+        SocketHandle(ls).close()
+
+        await ps.send("test 1", flags={})
+        s.close()
+        # This send should raise EPIPE
+        await ps.send("test 2", flags={})
+        SocketHandle(ps).close()
+
+
+    # The bug was, when the poll function handled EvError for us,
+    # our callbacks may never get executed, thus making the event
+    # loop block indefinitely. This is a timer to keep everything
+    # rolling. 400 ms is an arbitrary value, should be enough though.
+    proc timer() {.async.} =
+        await sleepAsync(400)
+        echo("Timer expired.")
+        quit(2)
+
+
+    asyncCheck(testAsyncSend())
+    waitFor(timer())