1373485 - Multiple webrtc gyp files are using pkg-config to find gtk+-2.0 cflags

Status: RESOLVED DUPLICATE of bug 1373804

(Core :: WebRTC, enhancement, P2)

Description

[Mike Hommey [:glandium]]

Considering libxul is mainly built against gtk+-3.0, it seems like a footgun that could blow up in the future.

$ git grep gtk+-2.0 media
media/webrtc/trunk/build/linux/system.gyp:            'gtk_packages': 'gmodule-2.0 gtk+-2.0 gthread-2.0',
media/webrtc/trunk/peerconnection.gyp:            '<!@(pkg-config --cflags gtk+-2.0)',
media/webrtc/trunk/peerconnection.gyp:              '<!@(pkg-config --libs-only-L --libs-only-other gtk+-2.0 gthread-2.0)',
media/webrtc/trunk/peerconnection.gyp:              '<!@(pkg-config --libs-only-l gtk+-2.0 gthread-2.0)',
media/webrtc/trunk/webrtc/media/BUILD.gn:      "gtk+-2.0",
media/webrtc/trunk/webrtc/media/media.gyp:            '<!@(pkg-config --cflags gobject-2.0 gthread-2.0 gtk+-2.0)',
media/webrtc/trunk/webrtc/webrtc_examples.gyp:                '<!@(pkg-config --cflags glib-2.0 gobject-2.0 gtk+-2.0)',
media/webrtc/trunk/webrtc/webrtc_examples.gyp:                      ' gobject-2.0 gthread-2.0 gtk+-2.0)',
media/webrtc/trunk/webrtc/webrtc_examples.gyp:                      ' gthread-2.0 gtk+-2.0)',

Comment 1

[Alex Chronopoulos [:achronop]]

I give a medium priority, please check if it is the appropriate.

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

We don't use system.gyp, BUILD.gn (yet), webrtc_examples.gyp.

We use peerconnection.gyp, but we put all but a little of it inside a condition of "build_with_mozilla==0", so this isn't executed.  It will go away when we switch to BUILD.gn.

We use media.gyp, but modified it to only build a small subset (mozilla_rtc_media instead of rtc_media -- really just two classes), so we don't ever look at the gtk stuff.

Comment 3

[Mike Hommey [:glandium]]

(In reply to Randell Jesup [:jesup] from comment #2)
> We don't use system.gyp, BUILD.gn (yet), webrtc_examples.gyp.
> 
> We use peerconnection.gyp, but we put all but a little of it inside a
> condition of "build_with_mozilla==0", so this isn't executed.  It will go
> away when we switch to BUILD.gn.
> 
> We use media.gyp, but modified it to only build a small subset
> (mozilla_rtc_media instead of rtc_media -- really just two classes), so we
> don't ever look at the gtk stuff.

Except we do, since that's how I found about it. See the pasted log in bug 1373486 comment 0.

Comment 4

[Randell Jesup [:jesup] (needinfo me)]

(In reply to Mike Hommey [:glandium] from comment #3)
> Except we do, since that's how I found about it. See the pasted log in bug
> 1373486 comment 0.

I see the grep, but that doesn't show a build log showing it getting tocuhed (though I have no evidence that you're wrong, either).  It was 4:30am when I posted that analysis (and it wasn't that I got up early), so I might have been wrong.  I hope it doesn't evaluate stuff in conditions that are false...  Can you post a log showing what touches gtk2?

Comment 5

[Mike Hommey [:glandium]]

As mentioned in the comment you replied to: bug 1373486 comment 0. Hint: it's not this bug.

Comment 6

[Randell Jesup [:jesup] (needinfo me)]

(In reply to Mike Hommey [:glandium] from comment #5)
> As mentioned in the comment you replied to: bug 1373486 comment 0. Hint:
> it's not this bug.

Ah.  I misread that as *this* bug, sorry.

So, after some experimentation: it appears as if gyp runs through the dependencies of every target, even if it isn't actually referenced.  Thus api.gyp:libjingle_peerconnection (which we have no interest in using) gets processed, causing it to invoke dependencies like media.api:rtc_media.  Even if I rename libjingle_peerconnection to foobar, it will still get processed.  So it looks like this is a bug (or surprising 'feature') in gyp.

So while it will run the pkg-config, we shouldn't end up using any of the results.  Still, it shouldn't be running it.

Can you try 'use_gtk': 0 in gyp.mozbuild?  The cflags entry is inside a use_gtk conditional.  In local tests, that seems to avoid the call to pkg-config.   use_gtk is only used for this one pkg-config call.