Some distros, notably Fedora, want to install non-core Perl libraries
into specific directory, namely /usr/share/perl5/vendor_perl.
The Makefile build system allows this by overriding perllibdir variable,
let's make meson works on par with our Makefile.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`generate_perl_command` needs `depends: [git_version_file]` and the uses
in top-level meson.build were fine, but the ones in perl/ weren't, causing
parallel build failures in some cases as GIT-BUILD-OPTIONS wasn't yet
available.
Signed-off-by: Sam James <sam@gentoo.org>
Acked-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>
These sites offer https versions of their content.
Using the https versions provides some protection for users.
Signed-off-by: Josh Soref <jsoref@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We set "use warnings" in most of our perl code to catch problems. But as
the name implies, warnings just emit a message to stderr and don't
otherwise affect the program. So our tests are quite likely to miss that
warnings are being spewed, as most of them do not look at stderr.
We could ask perl to make all warnings fatal, but this is likely
annoying for non-developers, who would rather have a running program
with a warning than something that refuses to work at all.
So instead, let's teach the perl code to respect an environment variable
(GIT_PERL_FATAL_WARNINGS) to increase the severity of the warnings. This
can be set for day-to-day running if people want to be really pedantic,
but the primary use is to trigger it within the test suite.
We could also trigger that for every test run, but likewise even the
tests failing may be annoying to distro builders, etc (just as -Werror
would be for compiling C code). So we'll tie it to a special test-mode
variable (GIT_TEST_PERL_FATAL_WARNINGS) that can be set in the
environment or as a Makefile knob, and we'll automatically turn the knob
when DEVELOPER=1 is set. That should give developers and CI the more
careful view without disrupting normal users or packagers.
Note that the mapping from the GIT_TEST_* form to the GIT_* form in
test-lib.sh is necessary even if they had the same name: the perl
scripts need it to be normalized to a perl truth value, and we also have
to make sure it's exported (we might have gotten it from the
environment, but we might also have gotten it from GIT-BUILD-OPTIONS
directly).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the CPAN modules that have lived under perl/Git/FromCPAN since my
20d2a30f8f ("Makefile: replace perl/Makefile.PL with simple make
rules", 2017-12-10) to perl/FromCPAN.
A subsequent change will teach the Makefile to only install these
copies of CPAN modules if a flag that distro packagers would like to
set isn't set. Due to how the wildcard globbing is being done it's
much easier to accomplish that if they're moved to their own
directory.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Đoàn Trần Công Danh