On Tue, Oct 16, 2018 at 03:40:01PM -0700, Jonathan Nieder wrote: > SZEDER Gábor wrote: > > On Tue, Oct 16, 2018 at 02:54:56PM -0700, Jonathan Nieder wrote: > >> SZEDER Gábor wrote: > > >>> Our Makefile has lines like these: > >>> > >>> CFLAGS = -g -O2 -Wall > >>> CC = cc > >>> AR = ar > >>> SPATCH = spatch > [...] > >>> I'm not sure what to do. I'm fine with updating our 'ci/' scripts to > >>> explicitly respect CC in the environment (either by running 'make > >>> CC=$CC' or by writing $CC into 'config.mak'). Or I could update our > >>> Makefile to use '?=' for specific variables, but: > >> > >> That's a good question. I don't have a strong opinion myself, so I > >> tend to trust larger projects like Linux to have thought this through > >> more, and they use 'CC = cc' as well. > > > > I don't think Linux is a good example to follow in this case, see e.g. > > 6d62c983f7 (Makefile: Change the default compiler from "gcc" to "cc", > > 2011-12-20) (in short: Git is supposed to be buildable with compilers > > other than GCC as well, while Linux not really, so they can hardcode > > 'CC = gcc'). > > Nowadays Linux builds with clang as well. People also have other > reasons to override the CC setting (cross-compiling, etc) and to > override other settings like CFLAGS. > > > Also, the projects I have on hand usually have 'CC = gcc' hardcoded in > > their Makefiles, too, but those Makefiles were generated by their > > ./configure script (which in turn by ./autogen.sh...), and those tend > > to write CC from the environment into the generated Makefiles. > > Yes, I think that's what makes travis's setup normally work. It makes > sense to me since ./configure is expected to have more implicit or > automatic behavior. For "make", I kind of like that it doesn't depend > on environment variables that I am not thinking about when debugging a > reported build problem. > > When building Git without autoconf, the corresponding place for > settings is config.mak. Would it make sense for the ci scripts to > write a config.mak file? A first I though it doesn't, but it turns out it acually does. 'ci/run-build-and-tests.sh' basically runs: make make test I naively put a 'CC=$CC' argument at the end of the first command, thinking it should Just Work... but then that second 'make test' got all clever on me, said "* new build flags", and then proceeded to rebuild everything with the default 'cc'. (With the additional complication, that on Travis CI we actually run 'make --quiet test', which rebuilds everything, well, quietly... so the rebuild itself is not even visible in the build logs.) So, then it's either 'config.mak', or passing a 'CC=$CC' argument to _all_ make commands, including those that are not supposed to build anything, but only run the tests. I find the latter aesthetically not particularly pleasing.
