More selective X11 dependencies

[MikeMcQuaid]

I think it's a bit nasty to just pushing users to XQuartz. I'd propose that common things like libpng are reintroduced as Homebrew dependencies and things like Qt which contain internal versions just use them instead of pulling in XQuartz.

I already did the latter here and will start working on the prior unless there is huge objections.

[adamv]

Seems reasonable, let's just think this through and get lots of code review before committing anything.

Certainly installing all of XQuartz is heavy just to get libpng.

[adamv]

We can use depends_on :libpng symbol dep to do smart things with user configuration, rather than adding direct deps. on a new libpng brew.

[MikeMcQuaid]

Yep, agreed. If they have XQuartz or another X11 installed, use that instead. I think this would still be useful on non-Mountain Lion too.

[jacknagel]

My main worry is another mess like Cairo where some things are linked against the xquartz version and some against our own version, and things that have transitive dependencies on both.

[jacknagel]

I'm certainly in favor of things using internal versions, though.

[MikeMcQuaid]

Good point on Cairo. In that situation I'd rather do what's best for the latest OSX (even if that means adding an unnecessary dep to lower versions).

[MikeMcQuaid]

You can see the start of my X11 work here: https://github.com/mikemcquaid/homebrew/compare/x11

What else do we want other than freetype, libpng?

[adamv]

fontconfig?

[adamv]

Maybe libpng should always be keg-only, even on Mountain Lion.

[MikeMcQuaid]

I don't think so as Apple ships an intentionally broken version.

[MikeMcQuaid]

I've made this stuff apply on Lion to save users installing X11 and will apply it soonish unless there's any huge objections as there are outstanding issues (#13638) that will be fixed by it.

[MikeMcQuaid]

I've pushed quite a bit more stuff (adding cairo, freetype, libpng, pixman, fontconfig and been testing with cairo, imagemagick and graphviz) so will leave it a few more days.

Am I right in assuming that stuff that depends on cairo usually always needs real X11 too (just for the default mode to compile it in)?

[2bits]

What is the key problem this is trying to solve? Is it the gigabyte of x11 libraries installed when some users may only want a few megs? Is it the 8 minutes it took to install XQuartz? Is it the size of the x11 tarball that's been up since February?

[2bits]

Sorry I think my sugar is low :-) Forget that stuff. Ima grab a beer. There's this Marin Brew Co. Bluberry Ale at my corner store.

[jacknagel]

No, I think it is worth answering those questions. With XQuartz we get everything we need in one shot. Do the benefits of this outweigh the minor inconvenience of installing XQuartz, along with the problems that will surely surface when users end up with things that are transitively dependent on both libs that we provide and that XQuartz provides? The cairo dupe, while necessary, has already caused this type of problem.

I feel like this needs to be addressed somehow before we paint ourselves into a corner.

[jacknagel]

(Note: not trying to be argumentative, I just think these things should be discussed and addressed before making hasty decisions).

[MikeMcQuaid]

I'd like it so the only people who install XQuartz are people who actually want to run X applications on OSX. I created this partly to scratch a personal itch as I don't run X applications on OSX but want to install ImageMagick with PNG support.

I'm happy for us to force the use of XQuartz libs for X11 applications (and Cairo; is there anything that uses that without X11?) if you feel that would avoid bugs (and because I don't use them).

[mxcl]

I agree.

Probably we can get away with just adding the formula and imaging XQuartz doesn't exist even. It's not a default install and it's in a weird place.

[2bits]

So should we pull the useful libraries out of all sorts of packages as we find them like macports does? Yuk.

[mxcl]

So should we pull the useful libraries out of all sorts of packages as we find them like macports does? Yuk.

Don't understand.

[MikeMcQuaid]

@2bits We should depend on as little as possible. If we have enough bottles at some point later we should also e.g. try and not depend on Xcode. Installing a piece of software only to be told to install another is a crappy user experience, unexpected on OSX and a bit lazy.

[MikeMcQuaid]

3895b9c and friends were merged. I'll go through and do the boring fixing of anything depending on :x11 later.

[adamv]

So what's our current best practice here? I can fix some of the :x11 deps if I know what to look for.

[MikeMcQuaid]

I've got as far as ffmpeg but feel free to continue. Basically uninstall/move X11/XQuartz (if you can) and brew install, see what fails and add the various X11 dependencies until it works.

[adamv]

Ah, I'm not on Mountain Lion, so presumably I can't do a good test of removing the dep.

[mxcl]

Superenv will forcibly remove X11 from paths if it is not a dep. Should be proper. If it doesn’t it's a bug in superenv.

[jacknagel]

Presumably this is done or mostly-done.

[MikeMcQuaid]

Yep, pretty much, thanks.