patch 8.2.0032: MS-Windows: test for blank job fails

Problem:    MS-Windows: test for blank job fails
Solution:   Check before escaping.

src/channel.c

@@ -5921,7 +5921,7 @@ job_start(
     {
 	// Command is a string.
 	cmd = argvars[0].vval.v_string;
-	if (cmd == NULL || *cmd == NUL)
+	if (cmd == NULL || *skipwhite(cmd) == NUL)
 	{
 	    emsg(_(e_invarg));
 	    goto theend;
@@ -5945,13 +5945,12 @@ job_start(
 	    goto theend;
 
 	// Empty command is invalid.
-#ifdef USE_ARGV
 	if (argc == 0 || *skipwhite((char_u *)argv[0]) == NUL)
 	{
 	    emsg(_(e_invarg));
 	    goto theend;
 	}
-#else
+#ifndef USE_ARGV
 	if (win32_build_cmd(l, &ga) == FAIL)
 	    goto theend;
 	cmd = ga.ga_data;

src/testdir/test_channel.vim

@@ -1962,6 +1962,8 @@ func Test_empty_job()
   " This was crashing on MS-Windows.
   call assert_fails('let job = job_start([""])', 'E474:')
   call assert_fails('let job = job_start(["   "])', 'E474:')
+  call assert_fails('let job = job_start("")', 'E474:')
+  call assert_fails('let job = job_start("   ")', 'E474:')
 endfunc
 
 " Do this last, it stops any channel log.

src/version.c

@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    32,
 /**/
     31,
 /**/