What the tinderbox is doing for you

Since I’ve asked for some help with the tinderbox also with some pretty expensive hardware (the registered ECC RAM), I should probably also explain well what my tinderbox is doing for the final users. Some of the stuff is what any tinderbox would do, but as I wrote before, a tinderbox alone is not enough since it only ties into a specific target, and there are more cases to test.

The basic idea of the tinderbox is that it’s better if I – as a developer – file bugs for the packages, rather than users: not only I know how to file the bug, and often I know how to fix the bug as well; there is the chance that the issue will be fixed without any user hitting it (and thus being turned down by the failure).

So let’s see what my effort is targeted to. First of all, the original idea from which this started was to assess the --as-needed problem to have some data about the related problems. From that idea the things started expanding: while I am still running the --as-needed tests (and this is pretty important because there is new stuff that gets added that fails to build with --as-needed!), I also started seeing failures with new versions of GCC, and new versions of autotools, and after a while this started being a full-blown QA project for me.

While, for instance, Patrick’s tinderbox focuses on the stable branch of Gentoo, I’m actually focusing on unstable and “future” branches. This means that it runs over the full ~arch tree (which is much bigger than the stable one), and sometimes even uses masked packages, such as GCC, or autoconf. This way we can assess whether unmasking a toolchain package is viable or if there are too many things failing to work with it still.

But checking for these things also became just the preamble for more bugs to come: since I’m already building everything, it’s easy to find any other kind of failure: kernel modules not working with the latest version, minimum-flag combinations failing, and probably most importantly parallel make failures (since the tinderbox builds in parallel). And from there to adding more QA safety checks, the step was very short.

Nowadays, among the other things, I end up filing bugs for:

  • fetch failures: since the tinderbox has to download all the packages, it has found more than a couple packages that failed to fetch entirely — while the mirroring system should already report failed fetches for mirrored packages, those with mirror restrictions don’t run through that;
  • the --as-needed failures: you probably know already why I think this flag is a godsend, and yet not all developers use it to test their packages when they add it to portage;
  • parallel make failures, and parallel make misses: not only the tinderbox runs with parallel make enabled, and thus hits the parallel make failures (that are to be worked around to avoid users hitting them keeping a bug open to track them ), but thanks to Kevin Pyle it also checks for direct make calls which is a double-win, as stuff that would otherwise not use parallel make does in the tinderbox and I can fix the to either use emake for all or emake -j1 and file a bug;
  • new (masked) toolchains: GCC 4.4, autoconf 2.65, and so on: building with them when they are still masked helps identifying the problems way before users might stumble into them;
  • failing testsuites: this was added together with GCC 4.4 since the new strict-aliasing system caused quite a bit of packages to fail at runtime rather than build-time; while this does not make the coverage perfect, it’s also very important to identify --as-needed failures for libraries not using --no-undefined;
  • invalid directories: some packages install documentation and man pages out of place; others still refer to the deprecated /usr/X11R6 path; since I’m installing all the packages fully, it’s easy to check for such cases; while these are often petty problems, the same check identifies misplaced Perl modules which is a prerequisite for improving the Perl handling in Gentoo;
  • pre-stripped files in packages: some packages even when compiling source code tend to strip files before installing them; this is bad when you need to track down a crash because just setting -ggdb in your flags is not going to be enough;
  • maintainer-mode rebuilds: when a package causes maintainer-mode rebuild, it often executes configure twice, which is pretty bad (sometimes it takes more to run that script than to build the package); most users won’t care to file bugs about them, since they probably wouldn’t know what they are either, while I can usually do that in batch;
  • file collisions, and unexpected automagic dependencies are also tested; while Patrick’s tinderbox cleans the root at every merge, like binary distributions do in their build servers, and finds missing mandatory dependencies, my approach is the same applied by Gentoo users: install everything together; this helps finding file collisions between packages as well as finding some corner cases where packages fail only if a package is installed.

There are more cases for which I file bug, and you can even see that from the tinderbox quite a few packages were dropped entirely as unfixable. The whole point of it is to make sure that what we package and deliver to users builds and especially builds as intended, respecting policies and not feigning to work.

Now that you know what it’s used for… please help .

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