Hi, for a long time now I wanted to make this observation in the hope it can be improved:
Mesa is painfully hard to bisect because of many things. The most common thing hindering bisect tasks is the fact some options values are constantly swapped to `true` to `enabled` and things like that. Even when there are some legacy-compatibility implemented to recognize one for the other, Meson looks to only be able to process the compatibility if and only if the build folder has been entirely cleaned-up first. So bisecting requires to clean-up the build folder on almost every bisecting step, and most of the bisecting steps also require to modify the options themselves. I wonder if there are some rooms to improve the bisecting experience: - either by implementing some working method like not doing random enable/true change one by one throughout the years but focusing at porting all of them at once, - either at making Meson accept one for the other in all cases. Then comes the silent breaking of enabled features requiring another feature to be enabled too to be working again, which also prevents to bisect properly because the same configure and build commands for the same feature may or may not produce a working installation given the commit that is tested while bisecting, this has been reported there: - https://gitlab.freedesktop.org/mesa/mesa/-/issues/12024 Then comes the usual renaming things like the `swrast` gallium driver option being split into by `llvmpipe` and `softpipe`, we can't probably avoid that, and I would be happy if in the future I and others would only have to deal with that. Do you you also experience similar problems when bisecting Mesa? Do you also face similar problems but some I may have not listed ? I focus myself on OpenGL on Xorg with GLX and on OpenCL (clover/rusticl) so other people bisecting other things like GL ES, EGL, Vulkan or even some drivers I'm not testing myself that much or not at all may experience other things I'm not aware of but making bisecting uneasy as well. An example of thing I don't test that much is zink, so problems like zink not being working while being installed given which commit is built is definitely something that makes bisecting painful, but it took me months to experience this problem myself only because I don't test zink that much myself, but I guess some people experience similar problems and pain with other features or components of Mesa. More info about that zink problem can be found there, but this is just yet one example among others: - https://gitlab.freedesktop.org/mesa/mesa/-/issues/12024 While I don't bisect zink that much myself, when I had to bisect r300 to discover what Meson option I needed to make it work again, I experienced the pain of having to rewrite Meson command line options and to clean-up the build on various bisecting steps. So I expect other people to experience similar problems I'm not aware of, only because they bisect other things in Mesa I don't bisect myself. Do you have any opinion on the topic and/or ideas to make bisecting Mesa easier? -- Thomas “illwieckz” Debesse
