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/conf.c

@@ -552,11 +552,6 @@ static int conf_choice(struct menu *menu)
 			continue;
 		}
 		sym_set_tristate_value(child->sym, yes);
-		for (child = child->list; child; child = child->next) {
-			indent += 2;
-			conf(child);
-			indent -= 2;
-		}
 		return 1;
 	}
 }

scripts/kconfig/lkc.h

@@ -89,7 +89,7 @@ void menu_add_visibility(struct expr *dep);
 struct property *menu_add_prompt(enum prop_type type, char *prompt, struct expr *dep);
 void menu_add_expr(enum prop_type type, struct expr *expr, struct expr *dep);
 void menu_add_symbol(enum prop_type type, struct symbol *sym, struct expr *dep);
-void menu_finalize(struct menu *parent);
+void menu_finalize(void);
 void menu_set_type(int type);
 
 extern struct menu rootmenu;

scripts/kconfig/menu.c

@@ -282,7 +282,7 @@ static void sym_check_prop(struct symbol *sym)
 	}
 }
 
-void menu_finalize(struct menu *parent)
+static void _menu_finalize(struct menu *parent, bool inside_choice)
 {
 	struct menu *menu, *last_menu;
 	struct symbol *sym;
@@ -296,7 +296,12 @@ void menu_finalize(struct menu *parent)
 		 * and propagate parent dependencies before moving on.
 		 */
 
-		if (sym && sym_is_choice(sym)) {
+		bool is_choice = false;
+
+		if (sym && sym_is_choice(sym))
+			is_choice = true;
+
+		if (is_choice) {
 			if (sym->type == S_UNKNOWN) {
 				/* find the first choice value to find out choice type */
 				current_entry = parent;
@@ -394,7 +399,7 @@ void menu_finalize(struct menu *parent)
 			}
 		}
 
-		if (sym && sym_is_choice(sym))
+		if (is_choice)
 			expr_free(parentdep);
 
 		/*
@@ -402,8 +407,8 @@ void menu_finalize(struct menu *parent)
 		 * moving on
 		 */
 		for (menu = parent->list; menu; menu = menu->next)
-			menu_finalize(menu);
-	} else if (sym) {
+			_menu_finalize(menu, is_choice);
+	} else if (!inside_choice && sym) {
 		/*
 		 * Automatic submenu creation. If sym is a symbol and A, B, C,
 		 * ... are consecutive items (symbols, menus, ifs, etc.) that
@@ -463,7 +468,7 @@ void menu_finalize(struct menu *parent)
 			/* Superset, put in submenu */
 			expr_free(dep2);
 		next:
-			menu_finalize(menu);
+			_menu_finalize(menu, false);
 			menu->parent = parent;
 			last_menu = menu;
 		}
@@ -582,6 +587,11 @@ void menu_finalize(struct menu *parent)
 	}
 }
 
+void menu_finalize(void)
+{
+	_menu_finalize(&rootmenu, false);
+}
+
 bool menu_has_prompt(struct menu *menu)
 {
 	if (!menu->prompt)

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) {