[Python-Dev] Community buildbots (was Re: User's complaints) (original) (raw)

Giovanni Bajo rasky at develer.com
Fri Jul 14 12:00:07 CEST 2006

Neal Norwitz <nnorwitz at gmail.com> wrote:

a longer beta period gives external developers more time to catch up, and results in less work for the end users. This is the part I don't get. For the external developers, if they care about compatibility, why aren't they testing periodically, regardless of alpha/beta releases?

Because it is a cost, and I don't want to waste my time if the trunk is unstable or whatnot. There is no official statement of the kind "all the real development is done in branches, the trunk is always very stable, feel free to grab it". Thus, we (external developers) assume that it's better to wait for the first alpha or beta before starting doing any testing. Personally, I won't touch something before the first beta: there are already enough known bugs when the alphas are shipped that I prefer to wait a little bit more.

In my case, the beta period is too short. It's already a great luck if, during the beta cycle, I'm not deep into some milestone or release cycle for my own software. It might well happen that I have barely time to notice a Python beta is out, but I can't afford spending any time on it because of time constraint. By the time I'm done with my own deadlines, Python final is already out. But for the sake of the argument and the rest of this mail, let's assume I have tons of spare time to dedicate to Python 2.5 beta testing.

My applications have several external dependencies (I wouldn't classify those as "many", but still around 6-7 libraries in average). For each of those libraries, there won't be Py2.5-ready RPM or Windows installer to grab and build. Most of the time, I have to download the source package, and try to build it. This also means hunting down and fixing Py2.5-related bugs in all those libraries before I can even boot my own application (which is what I would care about). Then I occasionally hit a core Python bug while doing so, which is good, but I have to sit and wait. Some libraries have very complex build process which are still distutils-based, but might require many other external C/C++ libraries, which need to be fetched and compiled just to setup the build environment.

Alternatively, I could cross my fingers and wait for all the maintainers of the external libraries to have spare time, and dedicate to Python 2.5 upgrading. If I'm lucky, by the time RC1 is out, most of them might have binary packages available for download, or at least have their (unstable) CVS/SVN trunk fixed for Python 2.5 (which means that I'll have to fetch that unstable version and basically perform a forced upgrade of the library, which might trigger another class of compatibility/feature/regression bugs in my application, not related at all to Python 2.5 by itself, but still needed to be dealt).

So I think it's useless to ask people to rush testing beta releases: it takes months to get the community synched, and will always take. It's also useless to point the finger to external developers if they don't test Python and there is a bug in a .0 release. Bugs happen. It's software that evolves. My own suggestion is that it's useless to stall a release for months to give external developers time to fix things. I think it's much better to "release early - release often", and just get the damn release out of the door. Usually, it's at that point that the whole community start working on it, and discover bugs. And so what? For production usage, .0 releases of libraries (let alone the interpreter of the language) are a no-go for all software, and I know that for a long time already. I don't ship an application of mine with a Python .0 release no matter what, no matter even if the whole testsuite passes and everything seems to work. I don't have enough benefits for the risks, so I'll wait for .1 or .2 release anyway. It's very fine by me if .0 release is actually the first "official" "beta" release for the community, when the core developers say "we're done" and external developers really start get things going.

If you really care about .0 stability from a purely commercial point-of-view (it's bad advertisement if many people complain if a major release is broken, etc. etc.), I might suggest you to coordinate with a small group of selected external developers maintaing the larger external packages (Twisted and others). You could put a list of those packages in the release PEP as showstoppers for the release: you should not get a .0 out if those packages are broken. I think this could help smooth out the process. If important external libraries work, many applications relying on it will mostly work as well. I personally don't think it's such a big problem if one has to fix a couple of things in a 100K-line application to adjust it to the new .0 release, even if it's actually because of a bug in Python itself.

Giovanni Bajo

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