kconfig: Document 'if' flattening logic

It is not obvious that this might refer to an 'if', making the code
pretty cryptic:

	if (menu->list && (!menu->prompt || !menu->prompt->text)) {

Kconfig keeps the 'if' menu nodes even after flattening. Reflect that in
the example to be accurate.

No functional changes. Only comments added.

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

diff --git a/config/menu.c b/config/menu.c
index dcf22008b2d6e4732d1e2785b0706395a8e1b071..af66065733bb636be638d72c9fe4492692462d28 100644 (file)
--- a/config/menu.c
+++ b/config/menu.c
@@ -532,6 +532,35 @@ void menu_finalize(struct menu *parent)
                        *ep = expr_alloc_one(E_LIST, NULL);
                        (*ep)->right.sym = menu->sym;
                }
+
+               /*
+                * This code serves two purposes:
+                *
+                * (1) Flattening 'if' blocks, which do not specify a submenu
+                *     and only add dependencies.
+                *
+                *     (Automatic submenu creation might still create a submenu
+                *     from an 'if' before this code runs.)
+                *
+                * (2) "Undoing" any automatic submenus created earlier below
+                *     promptless symbols.
+                *
+                * Before:
+                *
+                *      A
+                *      if ... (or promptless symbol)
+                *       +-B
+                *       +-C
+                *      D
+                *
+                * After:
+                *
+                *      A
+                *      if ... (or promptless symbol)
+                *      B
+                *      C
+                *      D
+                */
                if (menu->list && (!menu->prompt || !menu->prompt->text)) {
                        for (last_menu = menu->list; ; last_menu = last_menu->next) {
                                last_menu->parent = parent;