On Tue, Oct 18, 2011 at 10:45 AM, Damjan Jovanovic <damjan....@gmail.com>wrote:
> Hi > > Since the beginning, I've had issues with regression testing. Despite the > fact it's very useful, it takes forever, it's easy to make a mistake > (especially during "reverse regression testing"), users find it too long and > technical, and only a small minority of regressions are ever bisected. And > several patches need backporting to allow older versions of Wine to compile > and run on today's make, gcc, and libraries - this is the case even for the > 1.0.x releases from less than 3 years ago! > > The problem is of course compilation. "configure" takes at least 40 > seconds, without any way to speed it up on multi-core CPUs. "make" takes > 5 > minutes, and it's only taking longer as Wine gets bigger. Compilation is > fundamentally complex and technical to users. > > But what if we had precompiled binaries, and regression testing consisted > of just running different versions of Wine? > > Wine binaries take up about 122 MB and take over 5 minutes to compile. > There's now 35770 commits between 36def4af0ca85a1d0e66b5207056775bcb3b09ff > (Release 1.0) and "origin". That's about 4.4 terrabytes of storage and over > 4 months of compilation, if each of those versions had to be compiled and > installed into its own prefix, way beyond what most users are willing or > able to store or do. Most patches however end up affecting only a few binary > files in the end, and compiling successive versions allows "make" to be very > quick. > > So I've written a tool that compiles Wine and adds each commit's binaries > into a Git repository. It knows how to compile old versions of Wine > (currently as far back as 1.0). It knows that commits affecting only > ANNOUNCE, .gitignore, and files in dll/ or programs/ ending with .c and such > don't need to go through the endlessly slow "configure", only "make". It is > stateless: if interrupted, it can resume from the last successful commit. It > works around bugs in GNU make (you won't believe how many there are...). > > This tool compiled all 35000 or so commits from Wine 1.0 to around 4th > October 2011 in only 7 days, generating a Git repository of Wine binaries > that's only 26 gigabytes in size. Regression testing with binaries is a > pleasure: it takes only a few seconds :-) on each bisection. I bisected a 16 > step regression in just 20 minutes, and most of that time was spent running > the application and dealing with 2 X-server crashes. > > I haven't figured out how to make the binaries available to users. Few > users can clone a 26 gigabyte repository, and even fewer places can serve > that much to multiple users. Maybe Git can compress it further? The other > idea I had is that users should be able to regression test through a GUI > tool. Maybe the GUI tool can just download and run the +/- 122 MB binary > snapshots for specific commits, instead of having the entire binary > repository locally? > > Any other ideas? Would you like to see this tool? Can I send an attachment > with it? > > Thank you > Damjan Jovanovic > > Hi, while I agree that 26 GB is a lot for most people, it would be no problem for me. Long compilation times were exactly the most important factor that kept me away from testing regressions so far. And I think I am not the only one on this side, so even if the repository is that huge, I think it might still worth to grant at least a few people the possibility to clone it. If I could arrange with my VPS provider to buy more disk space, I would even be willing to hold a mirror of it online. I would also definiately like to see how it is all achieved. Regards, Ferenc Gergely Szilagyi
