SpiderMonkey dependency change for gjs 1.47.3

[philip chimento gmail com]

Hi list,

I'm told this is where I should write to inform downstream packagers of dependency changes in GNOME packages.

The gjs module has depended on SpiderMonkey 24 (variously known as js24 or mozjs24) for some time. By Monday I plan to release an unstable 1.47.3 which will depend on SpiderMonkey 31, the next ESR (extended support release) after 24. SpiderMonkey ESRs do not maintain API/ABI compatibility, and can be installed in parallel with each other. So it cannot be an upgrade to the SpiderMonkey 24 package.

SpiderMonkey 31 may need to be packaged for your distribution, in particular Ubuntu does not have a package for it yet. The official location to download the SpiderMonkey 31 source is: https://people.mozilla.org/~sstangl/mozjs-31.5.0.tar.bz2 (Sadly, this information is not well advertised by Mozilla.)

If you intend to package it I would suggest using this Ubuntu PPA package as a starting point, taken from here: https://launchpad.net/~ricotz/+archive/ubuntu/testing/+packages

- dsc - https://launchpad.net/~ricotz/+archive/ubuntu/testing/+files/mozjs31_31.5.0-0ubuntu1~15.10~wfg2.dsc

- orig source - https://launchpad.net/~ricotz/+archive/ubuntu/testing/+files/mozjs31_31.5.0.orig.tar.bz2

- debian files - https://launchpad.net/~ricotz/+archive/ubuntu/testing/+files/mozjs31_31.5.0-0ubuntu1~15.10~wfg2.debian.tar.xz

The package contains several patches backported from later versions of SpiderMonkey that make 31 work with later releases of some compilers. Without some of those patches, current versions of gcc and clang will error out.

Additionally, I'd like to give a heads up that I intend to continue porting gjs to subsequent ESRs of SpiderMonkey, in order to keep pace with modern _javascript_ features and performance improvements. The next one after 31 is 38. I don't know if I will be able to land that change in time for GNOME 3.24, but if not, then you should expect it in 3.26.

Best regards,

Philip Chimento