Comment by snnn

3 years ago

So for each optional feature we may need three build options:

1. Force enable 2. Enable if available 3. Force disable

Like,

   --enable_landlock=always
   --enable_landlock
   --disable_landlock

8 comments

snnn

Reply
glandium  3 years ago

My rule of thumb is that things should never be disabled automatically. Make the test hard fail and print a message that the feature can be disabled.

  • cperciva  3 years ago

    In my code I have a bunch of routines optimized for different platforms, e.g. using x86 AESNI instructions. Not all compilers support them, and they don't even make sense when compiling for a different CPU architecture.

    It's much simpler to say "enable this if we can compile it" rather than detecting the compiler and target platform and throwing a mess of conditional compilation into an autoconf script.

  • ComputerGuru  3 years ago

    That’s how you make unusable/uncompilable software. It might be a good rule for something security critical like ssh but not as a general rule.

    • glandium  3 years ago

      I'd rather have people complaining about having to run configure a bunch of times to disable several features they don't have the libraries for than complaining that a feature doesn't work (because it ended up being disabled without them knowing).

      Likewise, I'd rather distros figure out the hard way when a new release has a new feature and needs a new dependency rather than their users complain that a new feature is missing.

      Principle of least surprises.

xorcist  3 years ago

That's ... how autoconf works?

If you explicitly set the enable-landlock flag, configure will fail when the feature doesn't compile.