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authorUlf Magnusson <ulfalizer@gmail.com>2018-01-14 12:56:20 +0300
committerMasahiro Yamada <yamada.masahiro@socionext.com>2018-01-21 18:49:32 +0300
commit3e41ba05b6d60cd54e64639b308be62c12308a04 (patch)
tree9c99091340bd13b1a2b57077581598e8bbffe6a6 /scripts/kconfig
parenteea199b445f64c038b1d868bd52700510843ccd6 (diff)
downloadlinux-3e41ba05b6d60cd54e64639b308be62c12308a04.tar.xz
kconfig: Document SYMBOL_OPTIONAL logic
Not obvious, especially if you don't already know how choices are implemented. No functional changes. Only comments added. Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'scripts/kconfig')
-rw-r--r--scripts/kconfig/menu.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 47bec3434fef..7634d567e779 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -549,6 +549,15 @@ void menu_finalize(struct menu *parent)
sym->flags |= SYMBOL_WARNED;
}
+ /*
+ * For non-optional choices, add a reverse dependency (corresponding to
+ * a select) of '<visibility> && m'. This prevents the user from
+ * setting the choice mode to 'n' when the choice is visible.
+ *
+ * This would also work for non-choice symbols, but only non-optional
+ * choices clear SYMBOL_OPTIONAL as of writing. Choices are implemented
+ * as a type of symbol.
+ */
if (sym && !sym_is_optional(sym) && parent->prompt) {
sym->rev_dep.expr = expr_alloc_or(sym->rev_dep.expr,
expr_alloc_and(parent->prompt->visible.expr,