Thanks for the review, Martin. On Tue, Apr 05, 2011 at 09:00:25PM -0000, Martin Pitt wrote: > Out of interest, why is it necessary to have co-installable -dev > packages? Is that only for convenience, to avoid having e. g. a i386 > pbuilder/build chroot on amd64? So far I thought that multiarch was > pretty much a runtime-only thing.
In the grand scheme of things: because when cross-compiling, you may have to build part of your package for both the host and build architectures as part of a single package build. Various packages will build tools which they then execute as part of the build. In some cases, this means having both host and build versions of the build dependency installed. That's *very* frequently the case for libc-dev. Sorry to mislead you into thinking multiarch was runtime only. That was the scope of <https://wiki.ubuntu.com/MultiarchSpec>, but that's only one piece of the puzzle (the core around which everything else gets built). In the long term, I have my sights set much higher. :) > For limiting the breakage, would it be reasonable to ship a > /usr/include/asm symlink which points to the "main" architecture? Or > would that hide potential bugs too much? Where do you point the symlink, and what package do you include it in? You can't have each linux-libc-dev package shipping this symlink with a different target, that breaks co-installability. -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. Ubuntu Developer http://www.debian.org/ [email protected] [email protected] -- You received this bug notification because you are a member of Linaro Release Team, which is a direct subscriber. https://bugs.launchpad.net/bugs/750585 Title: [FFe] support for making linux-libc-dev coinstallable under multiarch Status in “linux” package in Ubuntu: New Bug description: FFe justification: now that multiarch support for runtime libraries in the base system is available in the archive, the next step in this process is multiarch coinstallability of -dev packages. Although most of the remaining work on multiarch -dev can and will take place in ppa for natty given where we are in the release cycle, any -dev package tree has at its root linux-libc-dev which is built from the 'linux' source package - the package which is updated more frequently than any other by SRU. Rather than trying to keep up with SRUs, or artificially inflating the version of a linux-libc-dev-only package build in ppa, it would be welcome if a multiarch-ready linux-libc-dev could be included in the archive for natty. Risks: anything that looks directly in /usr/include/asm for headers will have problems with this change; anything that uses the system include path from the compiler will not. My best efforts at examining the archive for this issue (see below for details) have turned up only four packages in main and universe that are affected: three C library implementations, and bash-completion. Updating these packages in concert is manageable (patch for eglibc is ready, patches for the others are in preparation), but there's always some risk that the text search on package sources has missed something, and there wouldn't be room for another full archive rebuild before release to catch other breakage. Details: In order to have coinstallable multiarch -dev packages of any sort, linux-libc-dev first needs to be coinstallable since libc-dev depends on it. This seems to be straightforward to achieve; only the asm directory needs to be moved to the multiarch directory path, all the other header files appear to be (sensibly) architecture-neutral and can be shared between architectures. The compiler will find /usr/include/<triplet>/asm for the corresponding architecture with no problems; I've done a number of test builds that work just fine this way. The only trouble is with software that walks the filesystem looking for asm/<foo>.h includes instead of trusting the compiler to resolve them. It's unlikely that software should need to do this since the asm headers should as a rule not be directly included from userspace anyway, but the chances are not zero. I didn't expect nearly as many packages to break as did by the move to /usr/lib/<triplet>, either, so it seems my faith in the sanity of upstream build systems is generally misplaced. And I don't think we have time to discover any resulting issues with another archive test rebuild and fix the resulting packages before the natty release. _______________________________________________ Mailing list: https://launchpad.net/~linaro-release Post to : [email protected] Unsubscribe : https://launchpad.net/~linaro-release More help : https://help.launchpad.net/ListHelp
