Allow and test for lazy uv_tcp_listen

src/uv-unix.c

@@ -481,14 +481,27 @@ out:
 
 int uv_tcp_listen(uv_tcp_t* tcp, int backlog, uv_connection_cb cb) {
   int r;
-
+  int fd;
-  assert(tcp->fd >= 0);
 
   if (tcp->delayed_error) {
     uv_err_new((uv_handle_t*)tcp, tcp->delayed_error);
     return -1;
   }
 
+  if (tcp->fd <= 0) {
+    if ((fd = uv__socket(AF_INET, SOCK_STREAM, 0)) == -1) {
+      uv_err_new((uv_handle_t*)tcp, errno);
+      return -1;
+    }
+
+    if (uv__stream_open(tcp, fd)) {
+      close(fd);
+      return -1;
+    }
+  }
+
+  assert(tcp->fd >= 0);
+
   r = listen(tcp->fd, backlog);
   if (r < 0) {
     uv_err_new((uv_handle_t*)tcp, errno);

test/test-bind-error.c

@@ -188,3 +188,15 @@ TEST_IMPL(bind_localhost_ok) {
 
   return 0;
 }
+
+
+TEST_IMPL(listen_without_bind) {
+  int r;
+  uv_tcp_t server;
+
+  uv_init();
+  r = uv_tcp_init(&server);
+  ASSERT(r == 0);
+  r = uv_tcp_listen(&server, 128, NULL);
+  ASSERT(r == 0);
+}

test/test-list.h

@@ -30,6 +30,7 @@ TEST_DECLARE   (bind_error_addrnotavail_2)
 TEST_DECLARE   (bind_error_fault)
 TEST_DECLARE   (bind_error_inval)
 TEST_DECLARE   (bind_localhost_ok)
+TEST_DECLARE   (listen_without_bind)
 TEST_DECLARE   (bind6_error_addrinuse)
 TEST_DECLARE   (bind6_error_addrnotavail)
 TEST_DECLARE   (bind6_error_fault)
@@ -82,6 +83,7 @@ TASK_LIST_START
   TEST_ENTRY  (bind_error_fault)
   TEST_ENTRY  (bind_error_inval)
   TEST_ENTRY  (bind_localhost_ok)
+  TEST_ENTRY  (listen_without_bind)
 
   TEST_ENTRY  (bind6_error_addrinuse)
   TEST_ENTRY  (bind6_error_addrnotavail)