<div dir="auto">On Wed, Dec 19, 2018 at 1:30 PM Dylan Baker <<a href="mailto:dylan@pnwbakers.com" target="_blank" rel="noreferrer">dylan@pnwbakers.com</a>> wrote: > > Quoting Nicolai Hähnle (2018-12-18 09:37:43) > > On 17.12.18 23:46, Dylan Baker wrote: > > > Quoting Marek Olšák (2018-12-17 12:25:29) > > >> On Mon, Dec 17, 2018 at 1:18 PM Eric Anholt <<a href="mailto:eric@anholt.net" target="_blank" rel="noreferrer">eric@anholt.net</a>> wrote: > > >> > > >> Eero Tamminen <<a href="mailto:eero.t.tamminen@intel.com" target="_blank" rel="noreferrer">eero.t.tamminen@intel.com</a>> writes: > > >> > > >> > Hi, > > >> > > > >> > On 17.12.2018 8.08, Marek Olšák wrote: > > >> > [...] > > >> >> I think one of the serious usability issues is that environment > > >> >> variables such as CFLAGS, CXXFLAGS, LDFLAGS, and PKG_CONFIG_PATH are not > > >> >> saved by meson for future reconfigures. > > >> > > > >> > I don't know what Meson is supposed to do, but to me that would be > > >> > a bug in a build tool. > > >> > > > >> > Re-configure is supposed to adapt SW to the changes in the build > > >> > environment, and environment variables are part of that (along with > > >> > command line options and SW installed to to the system). Build > > >> > configure tool deciding to "remember" some of those things instead > > >> > of checking the new situation, seems like a great opportunity for > > >> > confusion. > > >> > > >> A user-triggered reconfigure, sure. Recapture env vars then. But "git > > >> pull; ninja -C build" losing track of the configuration state is broken. > > >> We don't have to specify all of your meson -Doption=state configuration > > >> on every build, why should you need to specify your PKG_CONFIG_PATH > > >> configure options on every build? > > >> > > >> > > >> Thanks, Eric. > > >> > > >> Yes, meson behaves such that users have to set all environment variables for > > >> every "ninja" command that might reconfigure. > > >> > > >> I see 2 solutions: > > >> 1) meson needs to remember the relevant env vars > > >> 2) meson should FAIL to configure if any of the env vars are set (if it wants > > >> to ignore them) > > >> > > >> Marek > > > > > > Meson does remember the *_FLAGS variables. Those are translated on configure > > > into meson's internal ${lang}_args and ${lang}_link args. It does look like > > > those aren't remembered when --wipe is called though, I filed a bug for that: > > > <a href="https://github.com/mesonbuild/meson/issues/4650" rel="noreferrer noreferrer" target="_blank">https://github.com/mesonbuild/meson/issues/4650</a> > > > > I ran into this same problem and noticed that Meson is already able to > > *warn* about such changes. > > > > It should either ignore the changes, or better yet, fail. > > > > (Or even better: ignore environment variables entirely; IMO sourcing the > > environment implicitly in a build system with an explicit configure is > > just a broken design that was unfortunately inherited from plain make > > without really considering the UI implications.) > > I agree with this, as do most of the upstream meson developers. So do the > autotools developers, who recommend passing CFLAGS (and friends) as arguments > instead of as env variables: > > ./configure CFLAGS='-march=native -03' LDFLAGS='-O3' --enable-foo > > meson supports this using: > > meson -Dc_args='-march-native' -Dc_link_args='-O3' -Dfoo=true > > Meson basically inherited this from autotools, and in hindsight we shouldn't > have. > > I'm going to do 3 things I think: > - Update our documentation to strongly recommend -Dc_args and not CLFAGS > - Push for meson to warn about using environment variables and recommend command > line options. > - Push for meson to remove CFLAGS and friends support: > <a href="https://github.com/mesonbuild/meson/issues/4664" rel="noreferrer noreferrer" target="_blank">https://github.com/mesonbuild/meson/issues/4664</a> FWIW when I was talking about env vars, I was very much referring to ./configure CFLAGS=..., not the CFLAGS=... ./configure variant -- that's fraught with peril. An especially important one to be able to bake in is PKG_CONFIG_PATH. Having support for just doing it rather than knowing what the mapping to meson is would be rather preferable -- e.g. meson CFLAGS=... </div>