Use SO_UPDATE_CONNECT_CONTEXT to try fix windows errors.

Some further research also suggests that this is well know limitation of
winsock and failure to call this in combination with ConnectEx can be a
problem.

However, I cannot reproduce locally on my windows machine. Searching
suggests a timing error within the network stack - if we call net/
functions before the connect is actually setup, it will be in an invalid
state.

src/core/ev.c

@@ -2468,7 +2468,6 @@ Janet janet_ev_lasterr(void) {
                   msgbuf,
                   sizeof(msgbuf),
                   NULL);
-    if (!*msgbuf) snprintf(msgbuf, sizeof(msgbuf), "%d", code);
     char *c = msgbuf;
     while (*c) {
         if (*c == '\n' || *c == '\r') {
@@ -2477,6 +2476,8 @@ Janet janet_ev_lasterr(void) {
         }
         c++;
     }
+    size_t len = c - msgbuf;
+    snprintf(c, sizeof(msgbuf) - len, "(%d)", code);
     return janet_cstringv(msgbuf);
 }
 #else

src/core/net.c

@@ -196,6 +196,10 @@ void net_callback_connect(JanetFiber *fiber, JanetAsyncEvent event) {
         return; /* This apparently indicates we haven't yet gotten a connection */
     }
     const int no_error = NO_ERROR;
+    if (r == NO_ERROR) { /* Last sockopt worked, one more */
+        /* Put socket in a good state instead of an empty default state. */
+        r = setsockopt((SOCKET)stream->handle, SOL_SOCKET, SO_UPDATE_CONNECT_CONTEXT, NULL, 0);
+    }
 #else
     int res = 0;
     socklen_t size = sizeof(res);
@@ -256,9 +260,11 @@ void net_callback_accept(JanetFiber *fiber, JanetAsyncEvent event) {
                 return;
             }
             SOCKET lsock = (SOCKET) state->lstream->handle;
-            if (NO_ERROR != setsockopt((SOCKET) state->astream->handle, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
+            SOCKET asock = (SOCKET) state->astream->handle;
+
+            if (NO_ERROR != setsockopt(asock, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
                                        (char *) &lsock, sizeof(lsock))) {
-                janet_cancel(fiber, janet_cstringv("failed to accept connection"));
+                janet_cancel(fiber, janet_cstringv("failed to accept connection (accept context)"));
                 janet_async_end(fiber);
                 return;
             }
@@ -947,7 +953,7 @@ JANET_CORE_FN(cfun_net_getsockname,
     janet_fixarity(argc, 1);
     JanetStream *js = janet_getabstract(argv, 0, &janet_stream_type);
     if (js->flags & JANET_STREAM_CLOSED) janet_panic("stream closed");
-    struct sockaddr_storage ss;
+    char ss[sizeof(struct sockaddr_storage) + 64]; /* extra space */
     socklen_t slen = sizeof(ss);
     memset(&ss, 0, slen);
     if (getsockname((JSock)js->handle, (struct sockaddr *) &ss, &slen)) {
@@ -963,7 +969,7 @@ JANET_CORE_FN(cfun_net_getpeername,
     janet_fixarity(argc, 1);
     JanetStream *js = janet_getabstract(argv, 0, &janet_stream_type);
     if (js->flags & JANET_STREAM_CLOSED) janet_panic("stream closed");
-    struct sockaddr_storage ss;
+    char ss[sizeof(struct sockaddr_storage) + 64]; /* extra space */
     socklen_t slen = sizeof(ss);
     memset(&ss, 0, slen);
     if (getpeername((JSock)js->handle, (struct sockaddr *)&ss, &slen)) {

test/suite-ev.janet

@@ -232,7 +232,7 @@
   [stream]
   (defer (:close stream)
     # prevent immediate close
-    (ev/read stream 1)
+    (assert (ev/read stream 1) "stream should be open")
     (def [host port] (net/localname stream))
     (assert (= host test-host) "localname host server")
     (assert (= port (scan-number test-port)) "localname port server")