[gentoo-dev] acceptable alternatives to -Werror, was: Changing policy about -Werror

[Chí-Thanh Christopher Nguyễn]

Hi!

So from the discussion I gather that -Werror has both desirable and 
undesirable effects. Question is, can we somehow mitigate the undesirable 
effects while still retaining the desirable effects as much as possible?

Requirements:
* Bother the user enough that they will report the problem, but not enough 
that they will leave Gentoo for another distro, which means:
* Do not fail to build/install when a warning is encountered
* Do not silently install the package anyway when a warning is encountered

Rough suggestion:

1. Introduce a new value in ebuilds for PROPERTIES, named "warningfree" (or 
something similar for RESTRICT if that is preferable).
2. Introduce a new package set, named @broken-warningfree. If a package is in 
this set, emerge will display a notification each time it runs (like with 
@preserved-rebuild).
3. Extend install-qa-check.d/90gcc-warnings so that optionally all compiler 
warnings will be caught
4. If PROPERTIES="warningfree" is set, 90gcc-warnings catches all compiler 
warnings
5. If PROPERTIES="warningfree" is set, and there is a warning caught, add the 
package to the @broken-warningfree set on install
6. If there is no warning caught, remove the package from the 
@broken-warningfree set (if it is currently in there)
7. When ebuild maintainers remove -Werror from a package, they can set 
PROPERTIES="warningfree" at their discretion

Also possible is to introduce FEATURES="strict-warnings" or similar, which 
will cause the build to fail if warnings are encountered in a warningfree 
ebuild. I need to think more how this could work with binpkgs though.


Best regards,
Chí-Thanh Christopher Nguyễn