[webkit-dev] RFC: Removing feature flag defaults in build-webkit

[Konstantin Tokarev]

21.09.2017, 21:54, "Tim Horton" <timothy_horton at apple.com>:
> Hi, all!
>
> Would anybody mind if build-webkit stopped being a source of default values of feature flags?
>
> We have defaults for feature flags in FeatureDefines.xcconfig for Xcode, WebKitFeatures.cmake (and Options*.cmake for platform overrides) for CMake, and FeatureDefines.h for everyone. This is already a mess. But it gets worse!
>
> Right now, for both the Xcode and CMake builds, build-webkit overrides those with its own set of defaults (in FeatureList.pm). There is also currently an argument to fall back to the CMake defaults (--default-cmake-features) and ignore build-webkit’s defaults.
>
> It doesn’t make sense that build-webkit enables a different set of features than a plain ol’ ‘xcodebuild’ or ‘cmake’ in the root directory. It seems like we’ve mostly tried to keep them in sync, but that’s silly busywork for seemingly little benefit.
>
> If we do this, the effective changes would be as follows:
>
>> 1) The default values of feature flags would be specified in all of the usual places except FeatureList.pm
>> 2) build-webkit --help will no longer list the default value of feature flags
>> 3) It will be easier (but still not easy, yet) to reason about the default value of feature flags, and keep them in sync between different ways people build
>> 4) --default-cmake-features will go away, because it will always be true
>
> And things that wouldn’t change:
>
>> 1) You will still be able to use --FEATURE, --no-FEATURE, and --minimal arguments to build-webkit
>
> Any objections or things I’ve overlooked?

I think it would be more useful to have a single file (e.g. JSON) with options and their default values, and  generate all other lists from it.

>
> —Tim
> ,
>
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-- 
Regards,
Konstantin