Bash-5.2 patch 34: fix for parsing compound assignment while expanding alias

parse.y

@@ -6489,9 +6489,10 @@ parse_compound_assignment (retlenp)
      int *retlenp;
 {
   WORD_LIST *wl, *rl;
-  int tok, orig_line_number, assignok;
+  int tok, orig_line_number, assignok, ea, restore_pushed_strings;
   sh_parser_state_t ps;
   char *ret;
+  STRING_SAVER *ss;
 
   orig_line_number = line_number;
   save_parser_state (&ps);
@@ -6514,6 +6515,12 @@ parse_compound_assignment (retlenp)
 
   esacs_needed_count = expecting_in_token = 0;
 
+  /* We're not pushing any new input here, we're reading from the current input
+     source. If that's an alias, we have to be prepared for the alias to get
+     popped out from underneath us. */
+  ss = (ea = expanding_alias ()) ? pushed_string_list : (STRING_SAVER *)NULL;
+  restore_pushed_strings = 0;
+    
   while ((tok = read_token (READ)) != ')')
     {
       if (tok == '\n')			/* Allow newlines in compound assignments */
@@ -6537,7 +6544,16 @@ parse_compound_assignment (retlenp)
       wl = make_word_list (yylval.word, wl);
     }
 
+  /* Check whether or not an alias got popped out from underneath us and
+     fix up after restore_parser_state. */
+  if (ea && ss && ss != pushed_string_list)
+    {
+      restore_pushed_strings = 1;
+      ss = pushed_string_list;
+    }
   restore_parser_state (&ps);
+  if (restore_pushed_strings)
+    pushed_string_list = ss;
 
   if (wl == &parse_string_error)
     {