patch 8.2.4622: Vim9: crash with :execute and :finish

Problem:    Vim9: Crash with :execute and :finish. (Sergey Vlasov)
Solution:   Check for NULL. (closes #10011)

src/eval.c

@@ -2144,7 +2144,8 @@ getline_peek_skip_comments(evalarg_T *evalarg)
 	p = skipwhite(next);
 	if (*p != NUL && !vim9_comment_start(p))
 	    return next;
-	(void)eval_next_line(evalarg);
+	if (eval_next_line(evalarg) == NULL)
+	    break;
     }
     return NULL;
 }
@@ -2199,6 +2200,9 @@ eval_next_line(evalarg_T *evalarg)
 							   GETLINE_CONCAT_ALL);
     else
 	line = next_line_from_context(evalarg->eval_cctx, TRUE);
+    if (line == NULL)
+	return NULL;
+
     ++evalarg->eval_break_count;
     if (gap->ga_itemsize > 0 && ga_grow(gap, 1) == OK)
     {

src/testdir/test_vim9_script.vim

@@ -1830,6 +1830,24 @@ def Test_execute_cmd_vimscript()
   v9.CheckScriptSuccess(lines)
 enddef
 
+def Test_execute_finish()
+  # the empty lines are relevant here
+  var lines =<< trim END
+      vim9script
+
+      var vname = "g:hello"
+
+      if exists(vname) | finish | endif | execute vname '= "world"'
+
+      assert_equal('world', g:hello)
+
+      if exists(vname) | finish | endif | execute vname '= "world"'
+
+      assert_report('should not be reached')
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
 def Test_echo_cmd()
   echo 'some' # comment
   echon 'thing'

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4622,
 /**/
     4621,
 /**/