patch 7.4.1331

Problem:    Crash when closing the channel in a callback. (Christian J.
            Robinson)
Solution:   Take the callback out of the list before invoking it.

src/testdir/test_channel.vim

@@ -301,6 +301,8 @@ func Test_pipe()
   endtry
 endfunc
 
+""""""""""
+
 let s:unletResponse = ''
 func s:UnletHandler(handle, msg)
   let s:unletResponse = a:msg
@@ -319,6 +321,28 @@ func Test_unlet_handle()
   call s:run_server('s:unlet_handle')
 endfunc
 
+""""""""""
+
+let s:unletResponse = ''
+func s:CloseHandler(handle, msg)
+  let s:unletResponse = a:msg
+  call ch_close(s:channelfd)
+endfunc
+
+" Test that "unlet handle" in a handler doesn't crash Vim.
+func s:close_handle(port)
+  let s:channelfd = ch_open('localhost:' . a:port, s:chopt)
+  call ch_sendexpr(s:channelfd, "test", function('s:CloseHandler'))
+  sleep 10m
+  call assert_equal('what?', s:unletResponse)
+endfunc
+
+func Test_close_handle()
+  call s:run_server('s:close_handle')
+endfunc
+
+""""""""""
+
 func Test_open_fail()
   silent! let ch = ch_open("noserver")
   echo ch