Re: Meson feedback as a user

[Michael Catanzaro <mike catanzaro gmail com>]

All good guidelines!

On Fri, Nov 24, 2017 at 8:49 AM, Emmanuele Bassi <ebassi gmail com> 
wrote:
> - Try to avoid automatic feature detection; this makes it harder for 
> distributors and continuous integration systems to identify the 
> dependencies needed to build your project

I would use much stronger wording here. Automagic dependencies (meson's 
auto dependencies) are *evil*, a huge number of GNOME projects used 
them in their Autotools build systems, and believe some projects have 
dutifully ported them over to their new Meson build systems. Please 
pick reasonable true or false defaults for your project, and *fail the 
build* if a dependency for a feature is missing. Make the user 
explicitly disable the feature to proceed without the dependency. It's 
really, really unkind to distributions, Gentoo users, and anyone 
building your software to make features *silently disappear* if they 
don't magically know to have a certain BuildRequires.

There are some *very rare* cases where automagic dependencies actually 
do make sense. For example, WebKitGTK+ will automagically determine to 
build with OpenGL ES support rather than OpenGL support if OpenGL ES is 
available but not OpenGL, because in the end no feature is disabled, 
and if you have one but not the other it's very likely that's the one 
you intend to be used. But if neither one is installed, the build will 
*fail* until you decide what to do: GL support will not just disappear 
unless you explicitly turn it off.

Michael