Good developers don’t necessarily create good build systems

it’s very common for users to expect that good developers will be good at any part of the development process, so if they wrote a good software that works, they expect the build system is just as good, and that the tests are good, and that the documentation should be good. Increasingly, the last part of this starts to be understood not to be the case; there is a huge amount of very good software that just lacks documentation (cough FFmpeg cough). In truth, none of these parts are always the case.

Being a good developer is a complex matter; one might be a very good coder, and thus write code that just works or that is very optimised, but write it in a way that is so obfuscated that nobody can deal with it but the original coder. One might be a very good interface designer, and write software that is perfectly user friendly, so that the users just love to work with it, but have a backend that just doesn’t do what it should. One might have very clear documentation, but the software is just too badly written to be useful.

Build systems are just the same, writing a proper buildsystem is a complex matter. With proper, I mean a buildsystem that allows to do just anything the user might expect to be able to do with a build system. This does not only mean building the software, but also installing, choosing a different installation prefix, cross-compiling, if it makes sense, and choosing build options so that optional features might or might not be compiled.

I have written many posts about how people try to replace autotools and in my opinion fail; I already express my discontent with CMake, since it replaces autotools with something just as complex, that only seems to be easier because KDE people are being instructed on how to use it (just as they were instructed to wrongly use autotools before). I already said that in my opinion the only reason for which CMake makes sense to be used by KDE is supporting the Microsoft C++ compiler under Windows. But at least CMake, after a not-so-long time, is shaping up as being an acceptable build system, I have to give credit to Kitware for that. SCons and similar failed in a cosmic way.

But what I think is worse is when the developers are not even trying to replace autotools, but just don’t seem to understand them at all. I have said recently that I’m going to look into ragel for both LScube and xine. Ragel is a very nice piece of software, its code is very complex and the results are very good. I’m sure the author is a very good developer. But it’s not a very good build system manager.

The build system used by ragel, both release and trunk, uses autoconf for some basic discovery and to allow the user to choose the prefix, but then it uses custom-tailored makefiles, as well as a custom-made config.h file. So what is the problem with them? Well there are many, some of which are being worked around in the ebuild. For instance, the install phase does not support a DESTDIR variable, which is fundamental for almost any distribution to install the package in a temporary directory before packaging it (or in the case of Gentoo, merging it on the live filesystem); it also uses the CFLAGS variable for compiling C++ sources, which is not nice at all either.

You can guess that all these problems are solved very nicely by using automake instead of custom-tailored makefiles. But it’s not just this; when you check out ragel from the Subversion repository, it needs to be bootstrapped; part of the sources are built starting from ragel itself, but to enable/disable the regeneration of these, it’s not just checking if they are missing or what, you have to edit the configure.ac file to enable/disable checking for the tools needed (ragel, kelbt and gperf). Again, it’s not really a good idea.

I’ve sent a few patches to ragel-users to update the buildsystem; a few are to update the currently-used build system to at least support some basic features used by packagers, but then I was quite tired and decided to go with destroying the old buildsystem and replacing it with proper autotools. Why this? Because I found out that the old build system didn’t support out of tree builds either. And of course they were handling packaging manually, while autotools has a nice make dist and especially make distcheck target to take care of the source packaging step automatically.

I’m waiting to see if the maintainer(s) get in touch with me to see if they are intentioned to merge in the new buildsystem. I sincerely hope so, and if they are going to open up the repository of kelbt (hopefully with Git), I’d be glad to rework the buildsystem of that project too. Hopefully with the new buildsystems building ragel on OpenSolaris will be piece of cake (I’ll write more about what I’m doing with OpenSolaris in the next days).