patch 7.4.1249

Problem:    Crash when the process a channel is connected to exits.
Solution:   Use the file descriptor properly.  Add a test. (Damien)
            Also add a test for eval().

src/channel.c

@@ -698,10 +698,14 @@ channel_exe_cmd(int idx, char_u *cmd, typval_T *arg2, typval_T *arg3)
 	}
 	else
 	{
-	    typval_T	*tv = eval_expr(arg, NULL);
+	    typval_T	*tv;
 	    typval_T	err_tv;
 	    char_u	*json;
 
+	    /* Don't pollute the display with errors. */
+	    ++emsg_skip;
+	    tv = eval_expr(arg, NULL);
+	    --emsg_skip;
 	    if (is_eval)
 	    {
 		if (tv == NULL)
@@ -714,7 +718,8 @@ channel_exe_cmd(int idx, char_u *cmd, typval_T *arg2, typval_T *arg3)
 		channel_send(idx, json, "eval");
 		vim_free(json);
 	    }
-	    free_tv(tv);
+	    if (tv != &err_tv)
+		free_tv(tv);
 	}
     }
     else if (p_verbose > 2)
@@ -1119,7 +1124,8 @@ channel_read_json_block(int ch_idx, int id, typval_T **rettv)
 
 	    /* Wait for up to 2 seconds.
 	     * TODO: use timeout set on the channel. */
-	    if (channel_wait(channels[ch_idx].ch_fd, 2000) == FAIL)
+	    if (channels[ch_idx].ch_fd < 0
+			|| channel_wait(channels[ch_idx].ch_fd, 2000) == FAIL)
 		break;
 	    channel_read(ch_idx);
 	}

src/testdir/test_channel.py

@@ -52,7 +52,6 @@ class ThreadedTCPRequestHandler(socketserver.BaseRequestHandler):
                 decoded = [-1, '']
 
             # Send a response if the sequence number is positive.
-            # Negative numbers are used for "eval" responses.
             if decoded[0] >= 0:
                 if decoded[1] == 'hello!':
                     # simply send back a string
@@ -65,9 +64,27 @@ class ThreadedTCPRequestHandler(socketserver.BaseRequestHandler):
                     print("sending: {}".format(cmd))
                     thesocket.sendall(cmd.encode('utf-8'))
                     response = "ok"
+                elif decoded[1] == 'eval-works':
+                    # Send an eval request.  We ignore the response.
+                    cmd = '["eval","\\"foo\\" . 123", -1]'
+                    print("sending: {}".format(cmd))
+                    thesocket.sendall(cmd.encode('utf-8'))
+                    response = "ok"
+                elif decoded[1] == 'eval-fails':
+                    # Send an eval request that will fail.
+                    cmd = '["eval","xxx", -2]'
+                    print("sending: {}".format(cmd))
+                    thesocket.sendall(cmd.encode('utf-8'))
+                    response = "ok"
+                elif decoded[1] == 'eval-result':
+                    # Send back the last received eval result.
+                    response = last_eval
                 elif decoded[1] == '!quit!':
                     # we're done
                     sys.exit(0)
+                elif decoded[1] == '!crash!':
+                    # Crash!
+                    42 / 0
                 else:
                     response = "what?"
 
@@ -75,6 +92,10 @@ class ThreadedTCPRequestHandler(socketserver.BaseRequestHandler):
                 print("sending: {}".format(encoded))
                 thesocket.sendall(encoded.encode('utf-8'))
 
+            # Negative numbers are used for "eval" responses.
+            elif decoded[0] < 0:
+                last_eval = decoded
+
         thesocket = None
 
 class ThreadedTCPServer(socketserver.ThreadingMixIn, socketserver.TCPServer):

src/testdir/test_channel.vim

@@ -18,25 +18,14 @@ else
 endif
 
 func s:start_server()
+  " The Python program writes the port number in Xportnr.
+  call delete("Xportnr")
+
   if has('win32')
     silent !start cmd /c start "test_channel" py test_channel.py
   else
     silent !python test_channel.py&
   endif
-endfunc
-
-func s:kill_server()
-  if has('win32')
-    call system('taskkill /IM py.exe /T /F /FI "WINDOWTITLE eq test_channel"')
-  else
-    call system("pkill --full test_channel.py")
-  endif
-endfunc
-
-func Test_communicate()
-  call delete("Xportnr")
-  " The Python program writes the port number in Xportnr.
-  call s:start_server()
 
   " Wait for up to 2 seconds for the port number to be there.
   let cnt = 20
@@ -57,10 +46,28 @@ func Test_communicate()
   if len(l) == 0
     " Can't make the connection, give up.
     call s:kill_server()
-    return
+    call assert_false(1, "Can't start test_channel.py")
+    return -1
   endif
   let port = l[0]
+
   let handle = ch_open('localhost:' . port, 'json')
+  return handle
+endfunc
+
+func s:kill_server()
+  if has('win32')
+    call system('taskkill /IM py.exe /T /F /FI "WINDOWTITLE eq test_channel"')
+  else
+    call system("pkill --full test_channel.py")
+  endif
+endfunc
+
+func Test_communicate()
+  let handle = s:start_server()
+  if handle < 0
+    return
+  endif
 
   " Simple string request and reply.
   call assert_equal('got it', ch_sendexpr(handle, 'hello!'))
@@ -73,8 +80,29 @@ func Test_communicate()
   call assert_equal('added1', getline(line('$') - 1))
   call assert_equal('added2', getline('$'))
 
+  " Send an eval request that works.
+  call assert_equal('ok', ch_sendexpr(handle, 'eval-works'))
+  call assert_equal([-1, 'foo123'], ch_sendexpr(handle, 'eval-result'))
+
+  " Send an eval request that fails.
+  call assert_equal('ok', ch_sendexpr(handle, 'eval-fails'))
+  call assert_equal([-2, 'ERROR'], ch_sendexpr(handle, 'eval-result'))
+
   " make the server quit, can't check if this works, should not hang.
   call ch_sendexpr(handle, '!quit!', 0)
 
   call s:kill_server()
 endfunc
+
+" Test that a server crash is handled gracefully.
+func Test_server_crash()
+  let handle = s:start_server()
+  if handle < 0
+    return
+  endif
+  call ch_sendexpr(handle, '!crash!')
+
+  " kill the server in case if failed to crash
+  sleep 10m
+  call s:kill_server()
+endfunc

src/version.c

@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1249,
 /**/
     1248,
 /**/