[Mesa-dev] last call for autotools

[Nicolai Hähnle]

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 <eric at anholt.net> wrote:
>>
>>      Eero Tamminen <eero.t.tamminen at intel.com> 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:
> https://github.com/mesonbuild/meson/issues/4650

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.)

Cheers,
Nicolai


> 
> Dylan
> 
> 
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