On 05/10/2018 10:10, Simon McVittie wrote: > Control: tags -1 - moreinfo > > I think we're ready to upload gjs 1.54 to unstable for wider testing, > and Ubuntu are already doing the same thing. This could cause some > disruption in unstable, and will not migrate without removing some > packages on s390x, but does not require a mass-rebuild of dependent > packages: packages built against the old libgjs0g work fine with the > new one, except in the cases where versioned Breaks were used. > > The new mozjs version does not work on s390x, so to make gjs migrate, > we will need to do architecture-specific removals (I'm not sure whether > this should be from testing or unstable) of binaries from at least the > following source packages:
Fair enough. > gjs > gnome-characters > gnome-documents > gnome-maps > gnome-shell > gnome-sound-recorder > gnome-sushi > gnome-weather > gpaste > polari > seed-webkit2 > Is there a better way we can deal with packages like gdm3 (which require > gnome-shell at runtime) than "Architecture: amd64 arm64 armel..." with > a full list of all the architectures where mozjs60 is known to work? > Perhaps a (slightly spurious) Build-Depends on gjs, to make sure they > don't build uninstallable binary packages for s390x? A build-dep would be preferred, either on gjs or gnome-shell or whatever you deem appropriate. > On Mon, 13 Aug 2018 at 10:38:58 +0100, Simon McVittie wrote: >> libgjs.so.0 currently uses Spidermonkey 52 (mozjs52) and is packaged as >> libgjs0g. The latest upstream version uses Spidermonkey 60 (mozjs60), >> which I'm in the process of packaging. It isn't entirely clear to me >> whether this will require a gjs SONAME bump > > Because there have been queries about this: > > My conclusion was that it *does not* require a SONAME bump, and dependent > packages do not need to be rebuilt. I didn't rebuild GNOME Shell to test > the new libgjs0g, and my desktop works fine. > > libgjs0g 1.54.0-1 still has a Provides on libgjs0-libmozjs-52-0. This > is counterintuitive, but intentional. It's there to avoid needing a > transition in which every dependent package is rebuilt, which is not > actually necessary any more. > > Some background: in historical versions of gjs, the gjs-internals module > exposed mozjs ABI as gjs ABI, and was used by at least GNOME Shell. As a > result, the upstream developers should ideally have bumped the SONAME > every time they upgraded to a new, incompatible version of mozjs; > but because it wasn't, we worked around this with package names like > libgjs0a, libgjs0b, ..., libgjs0g, and per-ABI virtual package names like > libgjs0-libmozjs-38-0, with gjs' shlibs generating a dependency on both. > > The gjs-internals module was removed by upstream commit d3e2f861 between > versions 1.46.x and 1.47.0, in 2016. From that point on, libgjs can > more or less be treated like an ordinary library: there are no longer > any public symbols that expose mozjs ABI, and an application compiled > against one version can run with any later version (as long as it does > not make use of Mozilla-specific JavaScript syntaxes that has been > removed from mozjs, but a rebuild wouldn't fix or even detect that, > so versioned Breaks seem like a better tool to deal with it). > > When we updated to gjs (>= 1.47) and libgjs0f/libgjs0g in 2017, nobody > noticed that libgjs no longer has any public symbols that expose mozjs > ABI, so we assumed that the virtual packages were still necessary. As a > result, the shlibs continued to generate a dependency on the virtual > package libgjs0-libmozjs-52-0, and packages like gnome-shell and polari > now depend on that virtual package. To avoid needing to rebuild dependent > packages immediately and do a full transition, we continue to provide > it from this version: the justification is that this new libgjs has the > same ABI as the one that was built using mozjs52, even though it now > uses mozjs60. > > The new shlibs file does not generate a dependency on the virtual package, > so we do not need a libgjs0-libmozjs-60-0 virtual package, and packages > that have been rebuilt against gjs 1.54.x will simply have "Depends: > libgjs0g (>= 1.54.0)" like any other shared library; the only relic of > the package's unfortunate history is that the shared library package > name is libgjs0g, not the expected libgjs0. Sounds good. My only question: is cjs moving to mozjs60 too, so that we can remove mozjs52? Cheers, Emilio
