Motivation:
• faster builds (on an Intel Core i9-9900K):
( ../configure --disable-sanitizers && make -j8; )
19,47s user 2,78s system 395% cpu 5,632 total
( meson .. -Dmans=true -Ddocs=true -Dprefix=/usr && ninja; )
38,67s user 3,73s system 1095% cpu 3,871 total
• more approachable build system configuration in the
python-esque meson domain specific language instead of
the autotools m4 macro language
• built-in language server support thanks to ninja:
the required compile_commands.json is built automatically
and only needs to be linked from the source dir, e.g.:
ln -s build/compile_commands.json .
Changes:
• the embedded vcs version info format changed from e.g.
4.18-282-gabe46f69 (2020-05-16, branch "next")
to:
4.18-282-gabe46f69
I think it’s better to lose a little bit of detail for
the gained cleanliness of using meson’s vcs_tag()
• Drop unused xcb-event dependency.
• We can no longer enable sanitizers and debug options
based on whether we are in a release or non-release build,
because our new version logic runs at ninja build time,
not at meson configure time.
The new behavior is probably for the better in terms of
what people expect, and we can make the CI use address sanitizer
explicitly to ensure it is still exercised.
• We lose the AX_EXTEND_SRCDIR behavior, i.e. including the
path component of the parent of the source dir in all paths.
This was a trick we used for easier debugging, so that stack
traces would contain e.g. ../i3-4.18.1/src/main.c, instead of
just src/main.c.
The other mechanism (_i3_version symbol) that we have for including
the version number in the “backtrace full” (but not merely
“backtrace”) output of gdb still works.
• Release tarballs now use tar.xz. Why not.
Migration plan
This commit adds the meson build files to the tree, but does not remove
autotools yet. For the development phase, we will keep both build systems
functional (and built on travis).
Then, just before the i3 v4.19 release, we will remove autotools from the tree
and the release tarball will require meson to compile.
This way, we incentivize maintainers to change, while also offering them an easy
way out (if desired) by reverting the most recent commit. In practice, switching
a distribution package from autotools to meson should only be a few line change,
easier than applying the provided patch :). Take a look at the debian/ changes
in this commit for an example.
meson is broadly available everywhere that i3 is available: Both xorg-server and
systemd gained meson build files in 2017, so we can follow suit:
https://anholt.livejournal.com/52574.htmlhttps://in.waw.pl/~zbyszek/blog/systemd-meson.html
How do I?
For producing a coverage report, enable the b_coverage meson base option
and run ninja coverage-html:
% cd build
% meson .. -Db_coverage=true
% ninja
% ninja test
% ninja coverage-html
See also https://mesonbuild.com/howtox.html#producing-a-coverage-report
For using the address sanitizer, memory sanitizer or undefined behavior
sanitizer, use the b_sanitize meson base option:
% cd build
% meson .. -Db_sanitize=address
% ninja
See also https://mesonbuild.com/Builtin-options.html#base-options
related to #4086
meson only supports the top level (no subdirs), so this makes the transition
easier.
For this to work with autotools, we need to *disable* the subdir-objects option,
that autotools wants us to enable for forward-compatibility.
This results in a bunch of warnings at autoreconf-time, but we don’t care, given
that we intend to switch away from autotools. Both build systems working next to
each other (as best as they can) is more important.
related to #4086
The test runs `xrandr setmonitor`, which will otherwise affect any test
scheduled after 533-randr15.t, causing flakyness in t/217-NET_CURRENT_DESKTOP.t
for example.
