kconfig: forbid multiple entries with the same symbol in a choice

Commit 6a859f1a19d1 ("powerpc: unify two CONFIG_POWERPC64_CPU entries
in the same choice block") removed the only occurrence of this tricky
use case.

Disallow this pattern in choice_check_sanity() and revert commit
4d46b5b623e0 ("kconfig: fix infinite loop in sym_calc_choice()").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260330115736.1559962-1-masahiroy@kernel.org
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Signed-off-by: Nicolas Schier <nsc@kernel.org>

diff --git a/scripts/kconfig/parser.y b/scripts/kconfig/parser.y
index 6d1bbee38f5d16c71ce9dcb985a7df6ef43a94ba..5fb6f07b6ad292a3547eab47bec63837b042749b 100644 (file)
--- a/scripts/kconfig/parser.y
+++ b/scripts/kconfig/parser.y
@@ -159,14 +159,8 @@ config_stmt: config_entry_start config_option_list
                        yynerrs++;
                }
 
-               /*
-                * If the same symbol appears twice in a choice block, the list
-                * node would be added twice, leading to a broken linked list.
-                * list_empty() ensures that this symbol has not yet added.
-                */
-               if (list_empty(&current_entry->sym->choice_link))
-                       list_add_tail(&current_entry->sym->choice_link,
-                                     &current_choice->choice_members);
+               list_add_tail(&current_entry->sym->choice_link,
+                             &current_choice->choice_members);
        }
 
        printd(DEBUG_PARSE, "%s:%d:endconfig\n", cur_filename, cur_lineno);
@@ -546,11 +540,10 @@ static int choice_check_sanity(const struct menu *menu)
                        ret = -1;
                }
 
-               if (prop->menu != menu && prop->type == P_PROMPT &&
-                   prop->menu->parent != menu->parent) {
+               if (prop->menu != menu && prop->type == P_PROMPT) {
                        fprintf(stderr, "%s:%d: error: %s",
                                prop->filename, prop->lineno,
-                               "choice value has a prompt outside its choice group\n");
+                               "choice value must not have a prompt in another entry\n");
                        ret = -1;
                }
        }