While our Makefile supports both Asciidoc and AsciiDoctor, our Meson
build instructions only support the former. Wire up support for the
latter, as well.
Our Makefile always favors Asciidoc, but Meson will automatically figure
out which of both to use based on whether they are installed or not. To
keep compatibility with our Makefile it favors Asciidoc over Asciidoctor
in case both are available.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A topic to optionally build with meson, which has graduated to
'master' recently, has regressed the normal Makefile build, which
is being corrected.
* ps/build-hotfix:
meson: add options to override build information
GIT-VERSION-GEN: fix overriding GIT_BUILT_FROM_COMMIT and GIT_DATE
GIT-VERSION-GEN: fix overriding GIT_VERSION
Makefile: introduce template for GIT-VERSION-GEN
Makefile: drop unneeded indirection for GIT-VERSION-GEN outputs
Makefile: stop including "GIT-VERSION-FILE" in docs
We inject various different kinds of build information into build
artifacts, like the version string or the commit from which Git was
built. Add options to let users explicitly override this information
with Meson.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is possible to configure a Git build without Perl when disabling both
our test suite and all Perl-based features. In Meson, this can be
achieved with `meson setup -Dperl=disabled -Dtests=false`.
It was reported by a user that this breaks the Meson build because
gitweb gets built even if Perl was not discovered in such a build:
$ meson setup .. -Dtests=false -Dperl=disabled
...
../gitweb/meson.build:2:43: ERROR: Unable to get the path of a not-found external program
Fix this issue by introducing a new feature-option that allows the user
to configure whether or not to build Gitweb. The feature is set to
'auto' by default and will be disabled automatically in case Perl was
not found on the system.
Reported-by: Daniel Engberg <daniel.engberg.lists@pyret.net>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce support for the Meson build system, a "modern" meta build
system that supports many different platforms, including Linux, macOS,
Windows and BSDs. Meson supports different backends, including Ninja,
Xcode and Microsoft Visual Studio. Several common IDEs provide an
integration with it.
The biggest contender compared to Meson is probably CMake as outlined in
our "Documentation/technical/build-systems.txt" file. Based on my own
personal experience from working with both build systems extensively I
strongly favor Meson over CMake. In my opinion, it feels significantly
easier to use with a syntax that feels more like a "real" programming
language. The second big reason is that Meson supports Rust natively,
which may prove to be important given that the project may pick up Rust
as another language eventually.
Using Meson is rather straight-forward. An example:
```
# Meson uses out-of-tree builds. You can set up multiple build
# directories, how you name them is completely up to you.
$ mkdir build
$ cd build
$ meson setup .. -Dprefix=/tmp/git-installation
# Build the project. This also provides several other targets like
e.g. `install` or `test`.
$ ninja
# Meson has been wired up to support execution of our test suites.
# Both our unit tests and our integration tests are supported.
# Running `meson test` without any arguments will execute all tests,
# but the syntax supports globbing to select only some tests.
$ meson test 't-*'
# Execute single test interactively to allow for debugging.
$ meson test 't0000-*' --interactive --test-args=-ix
```
The build instructions have been successfully tested on the following
systems, tests are passing:
- Apple macOS 10.15.
- FreeBSD 14.1.
- NixOS 24.11.
- OpenBSD 7.6.
- Ubuntu 24.04.
- Windows 10 with Cygwin.
- Windows 10 with MinGW64, except for t9700, which is also broken with
our Makefile.
- Windows 10 with Visual Studio 2022 toolchain, using the Native Tools
Command Prompt with `meson setup --vsenv`. Tests pass, except for
t9700.
- Windows 10 with Visual Studio 2022 solution, using the Native Tools
Command Prompt with `meson setup --backend vs2022`. Tests pass,
except for t9700.
- Windows 10 with VS Code, using the Meson plug-in.
It is expected that there will still be rough edges in the current
version. If this patch lands the expectation is that it will coexist
with our other build systems for a while. Like this, distributions can
slowly migrate over to Meson and report any findings they have to us
such that we can continue to iterate. A potential cutoff date for other
build systems may be Git 3.0.
Some notes:
- The installed distribution is structured somewhat differently than
how it used to be the case. All of our binaries are installed into
`$libexec/git-core`, while all binaries part of `$bindir` are now
symbolic links pointing to the former. This rule is consistent in
itself and thus easier to reason about.
- We do not install dashed binaries into `$libexec/git-core` anymore,
so there won't e.g. be a symlink for git-add(1). These are not
required by modern Git and there isn't really much of a use case for
those anymore. By not installing those symlinks we thus start the
deprecation of this layout.
- We're targeting Meson 1.3.0, which has been released relatively
recently November 2023. The only feature we use from that version is
`fs.relative_to()`, which we could replace if necessary. If so, we
could start to target Meson 1.0.0 and newer, released in December
2022.
- The whole build instructions count around 3300 lines, half of which
is listing all of our code and test files. Our Makefiles are around
5000 lines, autoconf adds another 1300 lines. CMake in comparison
has only 1200 linescode, but it avoids listing individual files and
does not wire up auto-configuration as extensively as the Meson
instructions do.
- We bundle a set of subproject wrappers for curl, expat, openssl,
pcre2 and zlib. This allows developers to build Git without these
dependencies preinstalled, and Meson will fetch and build them
automatically. This is especially helpful on Windows.
Helped-by: Eli Schwartz <eschwartz@gentoo.org>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Patrick Steinhardt