From 7e3465f63a0a70641ed8e49f9d40ee613f7da586 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sat, 23 Mar 2024 17:51:01 +0900
Subject: kconfig: do not reparent the menu inside a choice block

The boolean 'choice' is used to list exclusively selected config
options.

You must not add a dependency between choice members, because such a
dependency would create an invisible entry.

In the following test case, it is impossible to choose 'C'.

[Test Case 1]

  choice
          prompt "Choose one, but how to choose C?"

  config A
          bool "A"

  config B
          bool "B"

  config C
          bool "C"
          depends on A

  endchoice

Hence, Kconfig shows the following error message:

  Kconfig:1:error: recursive dependency detected!
  Kconfig:1:      choice <choice> contains symbol C
  Kconfig:10:     symbol C is part of choice A
  Kconfig:4:      symbol A is part of choice <choice>
  For a resolution refer to Documentation/kbuild/kconfig-language.rst
  subsection "Kconfig recursive dependency limitations"

However, Kconfig does not report anything for the following similar code:

[Test Case 2]

  choice
         prompt "Choose one, but how to choose B?"

  config A
          bool "A"

  config B
          bool "B"
          depends on A

  config C
          bool "C"

  endchoice

This is because menu_finalize() reparents the menu tree when an entry
depends on the preceding one.

With reparenting, the menu tree:

  choice
   |- A
   |- B
   \- C

... will be transformed into the following structure:

  choice
   |- A
   |  \- B
   \- C

Consequently, Kconfig considers only 'A' and 'C' as choice members.
This behavior is awkward. The second test case should be an error too.

This commit stops reparenting inside a choice.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 scripts/kconfig/parser.y | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'scripts/kconfig/parser.y')

diff --git a/scripts/kconfig/parser.y b/scripts/kconfig/parser.y
index b45bfaf0a02b..7fb996612c96 100644
--- a/scripts/kconfig/parser.y
+++ b/scripts/kconfig/parser.y
@@ -515,7 +515,7 @@ void conf_parse(const char *name)
 		menu_add_prompt(P_MENU, "Main menu", NULL);
 	}
 
-	menu_finalize(&rootmenu);
+	menu_finalize();
 
 	menu = &rootmenu;
 	while (menu) {
-- 
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