[webkit-dev] Common build system (was Re: WebKit Wishes)

[Patrick Gansterer]

Am 31.01.2013 um 21:07 schrieb Dirk Pranke:

> On Thu, Jan 31, 2013 at 11:48 AM, Hugo Parente Lima
> <hugo.lima at openbossa.org> wrote:
>> On Wednesday, January 30, 2013 04:15:48 PM Maciej Stachowiak wrote:
>>> On Jan 30, 2013, at 3:24 PM, Dirk Pranke <dpranke at chromium.org> wrote:
>>>> On Wed, Jan 30, 2013 at 1:50 PM, Filip Pizlo <fpizlo at apple.com> wrote:
>>>>> Thanks for sharing this.
>>>>> 
>>>>> On Jan 30, 2013, at 1:28 PM, Eric Seidel <eric at webkit.org> wrote:
>>>>> 
>>>>> I wish we only had one build system (it were easy to add/remove/move
>>>>> files).
>>>>> 
>>>>> I believe changes like http://trac.webkit.org/changeset/74849 are an
>>>>> unhealthy sign for the project.  Adam is not the only person who has
>>>>> chosen
>>>>> to empty files instead of removing them.  The pain of updating 8 build
>>>>> system is so great, we jump through hoops to avoid it.  Which means it
>>>>> took
>>>>> us months to move JavaScriptCore/wtf to WTF, and will take us years to
>>>>> kill
>>>>> WebCore/platform.
>>>>> 
>>>>> 
>>>>> +1
>>>>> 
>>>>> This is a hard problem.  It is a problem worth solving.
>>>>> 
>>>>> Do you have more thoughts on this, particularly since you know quite well
>>>>> how both Xcode and gyp work?
>>>>> 
>>>>> I suspect this is one of those things that it would be hard to achieve
>>>>> consensus on since there are so many stakeholders.  But it may be
>>>>> fruitful
>>>>> to have a "what if" discussion about what this might look like.
>>>> 
>>>> I think we can solve this problem if we agree that we want to. I think
>>>> we haven't in the past mostly because we couldn't reach a consensus
>>>> that it was worth solving enough to really try.
>>>> 
>>>> I would love to see this fixed and would be glad to work on it. I
>>>> think we should at least pursue this far enough to fully understand
>>>> what our options are and what the costs and tradeoffs might be; does
>>>> anyone disagree, and is anyone else willing to help pitch in?
>>>> 
>>>> I think there are several possible ways we could solve this. One would
>>>> be to switch to a common meta-build system. My understanding is that
>>>> Apple's internal production build processes impose certain constraints
>>>> here that I don't fully understand, but I know we've discussed the
>>>> possibility of checking in generated project files as a workaround.
>>>> Maybe there are other options as well to those constraints? I would
>>>> love to discuss this further w/ someone from Apple ...
>>> 
>>> It's far simplest for us if:
>>> (a) There is an Xcode project (or a Makefile) that builds the Mac port
>>> checked in to source control. (b) The generated project invokes only tools
>>> that are part of the default Mac OS X install.
>>> 
>>> It may not be completely impossible to violate these requirements but it
>>> will require a lot of bureaucracy.
>>>> (Also, just to get this out of the way, I don't think gyp needs to be
>>>> the solution).
>>>> 
>>>> Another alternative would be to write a script that did support at
>>>> least the common use cases (add/move/delete files). There have been
>>>> attempts in the past, but they have foundered on at least some
>>>> perceived skepticism over how well this would work w/ XCode. That
>>>> said, I don't think we've really pushed this to see. At some point
>>>> this script might turn into a meta-meta-build system, which might be
>>>> silly but also be the shortest path to the finish line.
>>>> 
>>>> I suggest if there is interest in this we can start a new thread to
>>>> discuss further ...
>>> 
>>> My preference would be to use a common meta-build system with a comfortably
>>> human-readable and human-editable syntax, and checked in generated project
>>> files for those ports that need them.
>>> 
>>> I think a key to making this work is to get Chromium and the Apple Mac port
>>> onto a common build system, which will probably require both Google and
>>> Apple ponying up at least one person to work on this project for a
>>> reasonable period of time.
>>> 
>>> I think the plausible meta-build-systems to use would be CMake and Gyp, but
>>> in both cases it may be necessary to modify them to work well for everyone.
>>> 
>>> I'd also like to add that I think a key related issue to common build system
>>> is common feature configuration. The many different ways ports control
>>> their feature flags is super confusing. I've long wanted to implement
>>> common configuration management, but have not had time.
>> 
>> I have a patch trying to solve this issue for CMake based ports[1], the patch
>> still on going, but even a change affecting just 2-3 ports using the same build
>> system is a bit hard to get a consensus, so you can imagine how hard will be
>> to get a consensus over all WebKit ports.
>> 
>> [1] https://bugs.webkit.org/show_bug.cgi?id=103162
>> 
> 
> This is slightly off-topic, but I had thought that no one was actually
> using CMake; maybe I was mistaken and just none of the ports that
> build on webkit.org are? It looks like Blackberry and maybe a WinCE
> port uses CMake? Anyone else?

EFL uses CMake too.
4 EFL bots @ http://build.webkit.org
1 WinCE bot @ http://build.webkit.org
1 EFL bot as EWS

-- Patrick