patch 8.2.1979: "term_opencmd" option of term_start() is truncated

Problem:    "term_opencmd" option of term_start() is truncated. (Sergey
            Vlasov)
Solution:   Allocate the buffer to hold the command. (closes #7284)

src/terminal.c

@@ -3450,15 +3450,19 @@ term_after_channel_closed(term_T *term)
 	if (term->tl_finish == TL_FINISH_OPEN
 				   && term->tl_buffer->b_nwindows == 0)
 	{
-	    char buf[50];
+	    char    *cmd = term->tl_opencmd == NULL
-
-	    // TODO: use term_opencmd
-	    ch_log(NULL, "terminal job finished, opening window");
-	    vim_snprintf(buf, sizeof(buf),
-		    term->tl_opencmd == NULL
 				? "botright sbuf %d"
-			    : (char *)term->tl_opencmd, fnum);
+				: (char *)term->tl_opencmd;
+	    size_t  len = strlen(cmd) + 50;
+	    char    *buf = alloc(len);
+
+	    if (buf != NULL)
+	    {
+		ch_log(NULL, "terminal job finished, opening window");
+		vim_snprintf(buf, len, cmd, fnum);
 		do_cmdline_cmd((char_u *)buf);
+		vim_free(buf);
+	    }
 	}
 	else
 	    ch_log(NULL, "terminal job finished");

src/testdir/test_terminal.vim

@@ -567,10 +567,12 @@ func Test_terminal_finish_open_close()
   call assert_fails("call term_start(cmd, {'term_opencmd': 'split %d and %s'})", 'E475:')
   call assert_fails("call term_start(cmd, {'term_opencmd': 'split % and %d'})", 'E475:')
 
-  call term_start(cmd, {'term_finish': 'open', 'term_opencmd': '4split | buffer %d'})
+  call term_start(cmd, {'term_finish': 'open', 'term_opencmd': '4split | buffer %d | let g:result = "opened the buffer in a window"'})
   close!
   call WaitForAssert({-> assert_equal(2, winnr('$'))}, waittime)
   call assert_equal(4, winheight(0))
+  call assert_equal('opened the buffer in a window', g:result)
+  unlet g:result
   bwipe
 endfunc
 

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1979,
 /**/
     1978,
 /**/