[Development] Qt 6 buildsystem support requirements
Matthew Woehlke
mwoehlke.floss at gmail.com
Mon Jul 30 22:30:11 CEST 2018
On 2018-07-21 19:52, Jason Newton wrote:
> I wanted to mention that this is on my mind alot for a few years days
> as a user for a plethora of libraries. My conclusion for the build
> system with the brightest future is bazel [...]
No. Just, *no*.
Persistent build server? Java? No, thanks.
Maybe it's gotten better, but last I knew, bazel had no notion of
"installing" software, which is just a non-starter. It's also heavily
optimized for Google's internal usage, and (partly as a result)
basically does not play at all nicely with software that's intended to
exist in an open source, package-managed ecosystem.
(I'd be interested to know if there is *any* software packaged by any
FLOSS distribution that uses bazel...)
Basically, ask your distributors before even *considering* bazel. My
suspicion is they're going to tell you that they refuse to package
anything using it.
And... seriously, *Java*?! Talk about bloat-ware... As dependencies for
*a build tool* go, that's pretty insane. Especially if you're not
planning to use it to build Java code.
By comparison, CMake+ninja depend on... a C++ compiler. (Which is also
needed for Qt itself, of course, so...) I haven't really looked, but I'd
guess qmake is also pretty light-weight in the dependency department.
> Why the qt project may be interested in this in short is:
> -Fast and scaling bazel uses a long lived server technique that hangs
> around
Yeah... that's *just* the sort of thing we should be forcing on users...
It's even *more* of an anti-feature if some other build systems needs to
build Qt. (Yes, that happens.)
On a related note, "hermetic builds" is pretty ironic. Your *build*
might be hermetic, but bazel itself is *far* from... it's very reliant
on putting all its garbage in "magic locations" in your home directory,
unlike most build tools that only need to write to your build directory.
Again, *not* friendly for anyone that needs to build Qt as an external
dependency.
> The amount of time that useful work is being performed is greater
> than I've observed in large cmake projects, even using ninja (assuming
> ninja would work across projects that size, due to frequent make
> sensitivities)
Um... very few projects don't work with Ninja, and I've seen plenty of
very large projects that *do*.
> -Ability to build external libraries from source
Yeah... no. Building third party libraries yourself is *evil*. And a
great way to piss off package maintainers. No open source project should
*EVER* rely on, or preferably even use by default, this ability.
On 2018-07-22 06:11, Kevin Kofler wrote:
> There is also little to no documentation on packaging Bazel-using software
> for GNU/Linux distributions. E.g., the Fedora wiki does not contain a single
> reference to Bazel.
There's a *reason* why that's so...
--
Matthew
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