patch 9.1.0481: Vim9: term_getjob() throws an exception on error

Problem:  Vim9: term_getjob() throws an exception on error
Solution: Return null_job instead, when there is no job
          (Ernie Rael)

closes: #14984

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/terminal.txt

@@ -1,4 +1,4 @@
-*terminal.txt*	For Vim version 9.1.  Last change: 2024 Jun 08
+*terminal.txt*	For Vim version 9.1.  Last change: 2024 Jun 13
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -647,7 +647,8 @@ term_getcursor({buf})					*term_getcursor()*
 term_getjob({buf})					*term_getjob()*
 		Get the Job associated with terminal window {buf}.
 		{buf} is used as with |term_getsize()|.
-		Returns |v:null| when there is no job.
+		Returns |v:null| when there is no job. In Vim9 script, return
+		null_job when there is no job.
 
 		Can also be used as a |method|: >
 			GetBufnr()->term_getjob()

src/terminal.c

@@ -6171,8 +6171,16 @@ f_term_getjob(typval_T *argvars, typval_T *rettv)
     buf = term_get_buf(argvars, "term_getjob()");
     if (buf == NULL)
     {
-	rettv->v_type = VAR_SPECIAL;
-	rettv->vval.v_number = VVAL_NULL;
+	if (in_vim9script())
+	{
+	    rettv->v_type = VAR_JOB;
+	    rettv->vval.v_job = NULL;
+	}
+	else
+	{
+	    rettv->v_type = VAR_SPECIAL;
+	    rettv->vval.v_number = VVAL_NULL;
+	}
 	return;
     }
 

src/testdir/test_vim9_builtin.vim

@@ -4557,6 +4557,7 @@ enddef
 def Test_term_getjob()
   CheckRunVimInTerminal
   v9.CheckSourceDefAndScriptFailure(['term_getjob(0z10)'], ['E1013: Argument 1: type mismatch, expected string but got blob', 'E1220: String or Number required for argument 1'])
+  v9.CheckSourceDefAndScriptSuccess(['assert_true(term_getjob(0) == null_job)'])
 enddef
 
 def Test_term_getline()

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    481,
 /**/
     480,
 /**/