patch 7.4.1665

Problem:    Crash when calling job_start() with a NULL string. (Dominique)
Solution:   Check for an invalid argument.

src/channel.c

@@ -3812,6 +3812,11 @@ job_start(typval_T *argvars)
     {
 	/* Command is a string. */
 	cmd = argvars[0].vval.v_string;
+	if (cmd == NULL || *cmd == NUL)
+	{
+	    EMSG(_(e_invarg));
+	    return job;
+	}
 #ifdef USE_ARGV
 	if (mch_parse_cmd(cmd, FALSE, &argv, &argc) == FAIL)
 	    return job;

src/testdir/test_channel.vim

@@ -1201,5 +1201,10 @@ func Test_close_callback()
   call s:run_server('s:test_close_callback')
 endfunc
 
+func Test_job_start_invalid()
+  call assert_fails('call job_start($x)', 'E474:')
+  call assert_fails('call job_start("")', 'E474:')
+endfunc
+
 " Uncomment this to see what happens, output is in src/testdir/channellog.
 " call ch_logfile('channellog', 'w')

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1665,
 /**/
     1664,
 /**/