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

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

[Ulf Magnusson]

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@gmail.com>
---
 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

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

[Ulf Magnusson]

On Wed, Oct 4, 2017 at 1:25 AM, Ulf Magnusson <ulfalizer@gmail.com> wrote:
> 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@gmail.com>
> ---
>  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
>

A patch to fix the compiler optimization level choice has been
submitted as well:
https://lkml.org/lkml/2017/10/3/991

Cheers,
Ulf

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

[Ulf Magnusson]

On Wed, Oct 4, 2017 at 2:10 AM, Ulf Magnusson <ulfalizer@gmail.com> wrote:
> On Wed, Oct 4, 2017 at 1:25 AM, Ulf Magnusson <ulfalizer@gmail.com> wrote:
>> 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@gmail.com>
>> ---
>>  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
>>
>
> A patch to fix the compiler optimization level choice has been
> submitted as well:
> https://lkml.org/lkml/2017/10/3/991
>
> Cheers,
> Ulf

Adding some CCs just because I forgot. No panic.

Cheers,
Ulf

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

[Masahiro Yamada]

2017-10-04 8:25 GMT+09:00 Ulf Magnusson <ulfalizer@gmail.com>:
> 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@gmail.com>
> ---

Applied to linux-kbuild/kconfig.
Thanks!

-- 
Best Regards
Masahiro Yamada