[PATCH] kconfig: Warn if choice default is not in choice

From: Ulf Magnusson
Date: Tue Oct 03 2017 - 19:26:49 EST


This will catch mistakes like in the following real-world example, where
a "CONFIG_" prefix snuck in, making an undefined symbol the default:

choice
prompt "Compiler optimization level"
default CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE

config CC_OPTIMIZE_FOR_PERFORMANCE
...

config CC_OPTIMIZE_FOR_SIZE
...

endchoice

This now prints the following warning:

init/Kconfig:1036:warning: choice default symbol 'CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE' is not contained in the choice

Cases where the default symbol belongs to the wrong choice are also
detected.

(The mistake is harmless here: Since the default symbol is not visible,
the choice falls back on using the first visible symbol as the default,
which is CC_OPTIMIZE_FOR_PERFORMANCE, as intended.)

Discovered while playing around with Kconfiglib
(https://github.com/ulfalizer/Kconfiglib).

Signed-off-by: Ulf Magnusson <ulfalizer@xxxxxxxxx>
---
scripts/kconfig/menu.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index e935793..ce88de8 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -252,6 +252,16 @@ static void sym_check_prop(struct symbol *sym)
"'%s': number is invalid",
sym->name);
}
+ if (sym_is_choice(sym)) {
+ struct property *choice_prop =
+ sym_get_choice_prop(sym2);
+
+ if (!choice_prop ||
+ prop_get_symbol(choice_prop) != sym)
+ prop_warn(prop,
+ "choice default symbol '%s' is not contained in the choice",
+ sym2->name);
+ }
break;
case P_SELECT:
case P_IMPLY:
--
2.7.4