patch 7.4.1616
Problem:    Malformed channel request causes a hang.
Solution:   Drop malformed message. (Damien)
diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index 6d38bff..c628bbe 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -123,10 +123,12 @@
     " check that no job is handled correctly
     call assert_equal('no process', string(ch_getjob(handle)))
   endif
-
   " Simple string request and reply.
   call assert_equal('got it', ch_evalexpr(handle, 'hello!'))
 
+  " Malformed command should be ignored.
+  call assert_equal('ok', ch_evalexpr(handle, 'malformed'))
+
   " Request that triggers sending two ex commands.  These will usually be
   " handled before getting the response, but it's not guaranteed, thus wait a
   " tiny bit for the commands to get executed.