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2026-02-04meson: wire up gitk and git-guiPatrick Steinhardt
Wire up both gitk and git-gui in Meson as subprojects. These two programs should be the last missing pieces for feature compatibility with our Makefile for distributors. Note that Meson expects subprojects to live in the "subprojects/" directory. Create symlinks to fulfill this requirement. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-06meson: make GIT_HTML_PATH configurableD. Ben Knoble
Makefile-based builds can configure Git's internal HTML_PATH by defining htmldir, which is useful for packagers that put documentation in different locations. Gentoo, for example, uses version-suffixed directories like ${prefix}/share/doc/git-2.51 and puts the HTML documentation in an 'html' subdirectory of the same. Propagate the same configuration knob to Meson-based builds so that "git --html-path" on such systems can be configured to output the correct directory. Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-10-02meson: add infrastructure to build internal Rust libraryPatrick Steinhardt
Add the infrastructure into Meson to build an internal Rust library. Building the Rust parts of Git are for now entirely optional, as they are mostly intended as a test balloon for both Git developers, but also for distributors of Git. So for now, they may contain: - New features that are not mission critical to Git and that users can easily live without. - Alternative implementations of small subsystems. If these test balloons are successful, we will eventually make Rust a mandatory dependency for our build process in Git 3.0. The availability of a Rust toolchain will be auto-detected by Meson at setup time. This behaviour can be tweaked via the `-Drust=` feature toggle. Next to the linkable Rust library, also wire up tests that can be executed via `meson test`. This allows us to use the native unit testing capabilities of Rust. Note that the Rust edition is currently set to 2018. This edition is supported by Rust 1.49, which is the target for the upcoming gcc-rs backend. For now we don't use any features of Rust that would require a newer version, so settling on this old version makes sense so that gcc-rs may become an alternative backend for compiling Git. If we _do_ want to introduce features that were added in more recent editions of Rust though we should reevaluate that choice. Inspired-by: Ezekiel Newren <ezekielnewren@gmail.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-18meson: work around broken system PCRE2 dependency in macOSCarlo Marcelo Arenas Belón
macOS provides a PCRE2 library in base that is not usable and not configured properly, as it installs a pkgconf module that points to a non-existent pcre2.h header in /usr/local/include. Detect that case and if the feature is enabled, try to fallback to a wrapped subproject through an anonymous dependency, aborting with an error if that is not possible. Change the feature to "auto" and print a warning and disable it if a broken dependency was detected, but to keep consistency with the cmake build system used on Windows, add a special rule to re-enable the pcre2 feature by default there. Helped-by: Eric Sunshine <sunshine@sunshineco.com> Suggested-by: Eli Schwartz <eschwartz@gentoo.org> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-27Merge branch 'rj/build-tweaks-part2'Junio C Hamano
Updates to meson-based build procedure. * rj/build-tweaks-part2: configure.ac: upgrade to a compilation check for sysinfo meson.build: correct setting of GIT_EXEC_PATH meson: correct path to system config/attribute files meson: correct install location of YAML.pm meson.build: quote the GITWEBDIR build configuration
2025-05-19meson: correct path to system config/attribute filesRamsay Jones
The path to the system-wide config and attributes files are not being set correctly in the meson build. Unless explicitly overridden on the command line during setup, the 'gitconfig' and 'gitattributes' options are defaulting to absolute paths in the '/etc' system directory. This is only appropriate if the <prefix> is set specifically to '/usr'. The directory in which these files are placed is generally referred to as the 'system configuration directory' or 'sysconfdir' for short. When the prefix is '/usr' then the sysconfdir is usually set to '/etc', but any other value for prefix results in the relative directory value 'etc' instead. (eg if prefix is '/usr/local', then the 'etc' relative value results in a system configuration directory of '/usr/local/etc'). When setting the 'sysconfdir' builtin option value, the meson system uses exactly this algorithm, so we can use get_option('sysconfdir') directly when setting the (non-overridden) build variables. In order to allow for overriding from the command line, remove the default values specified for the 'gitconfig' and 'gitattributes' options in the 'meson_options.txt' file. This allows the user to specify any pathname for those options, while being able to test for the unset (empty) value. An absolute pathname will be used unchanged and a relative pathname will be appended to '<prefix>/'. These values are then used to set the 'ETC_GITCONFIG' and 'ETC_GITATTRIBUTES' build variables which are, in turn, passed to the compiler as '-D' arguments. When the 'gitconfig' or 'gitattributes' options are not used, then use the built-in 'sysconfdir' and set the ETC_GITCONFIG build variable to the string "<sysconfdir>/gitconfig". Similarly, set ETC_ATTRIBUTES to "<sysconfdir>/gitattributes". Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-15Merge branch 'dd/meson-perl-custom-path'Junio C Hamano
Meson-based build framework update. * dd/meson-perl-custom-path: meson: allow customize perl installation path
2025-05-08meson: allow customize perl installation pathĐoàn Trần Công Danh
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>
2025-04-28meson: wire up benchmarking optionsPatrick Steinhardt
Wire up a couple of benchmarking options that we end up writing into our "GIT-BUILD-OPTIONS" file. These options allow users to control how exactly benchmarks are executed. Note that neither `GIT_PERF_MAKE_COMMAND` nor `GIT_PERF_MAKE_OPTS` are exposed as a build option. Those options are used by "t/perf/run", which is not used by Meson. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-28meson: wire up benchmarksPatrick Steinhardt
Wire up benchmarks in Meson. The setup is mostly the same as how we wire up our tests. The only difference is that benchmarks get wired up via the `benchmark()` option instead of via `test()`, which gives them a bit of special treatment: - Benchmarks never run in parallel. - Benchmarks aren't run by default when tests are executed. - Meson does not inject the `MALLOC_PERTURB` environment variable. Using benchmarks is quite simple: ``` $ meson setup build # Run all benchmarks. $ meson test -C build --benchmark # Run a specific benchmark. $ meson test -C build --benchmark p0000-* ``` Other than that the usual command line arguments accepted when running tests are also accepted when running benchmarks. Note that the benchmarking target is somewhat limited because it will only run benchmarks for the current build. Other use cases, like running benchmarks against multiple different versions of Git, are not currently supported. Users should continue to use "t/perf/run" for those use cases. The script should get extended at one point in time to support Meson, but this is outside of the scope of this series. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16meson.build: set default help format to html on windowsRamsay Jones
The build variable DEFAULT_HELP_FORMAT has an appropriate default ('man') set in the code, so there is no need to pass the -Define on the compiler command-line, unless the build requires a non-standard value. In addition, on windows the make build overrides the default help format to 'html', rather than 'man', in the 'config.mak.uname' file. In order to suppress the -Define on the C compiler command-line, only add the -Define to the 'libgit_c_args' variable when the requested value is not the standard 'man'. In order to override the default value on windows, add a 'platform' value to the 'default_help_format' combo option and set it as the default choice. When this option is set to 'platform', use the 'host_machine.system()' method call to determine the appropriate default value for the host system. Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-03Merge branch 'ps/meson-contrib-bits'Junio C Hamano
Update meson-based build procedure to cover contrib/ and other places as well. * ps/meson-contrib-bits: ci: exercise credential helpers ci: fix propagating UTF-8 test locale in musl-based Meson job meson: wire up static analysis via Coccinelle meson: wire up git-contacts(1) meson: wire up credential helpers contrib/credential: fix compilation of "osxkeychain" helper contrib/credential: fix compiling "libsecret" helper contrib/credential: fix compilation of wincred helper with MSVC contrib/credential: fix "netrc" tests with out-of-tree builds GIT-BUILD-OPTIONS: propagate project's source directory
2025-03-03Merge branch 'ps/build-meson-fixes-0130'Junio C Hamano
Assorted fixes and improvements to the build procedure based on meson. * ps/build-meson-fixes-0130: gitlab-ci: restrict maximum number of link jobs on Windows meson: consistently use custom program paths to resolve programs meson: fix overwritten `git` variable meson: prevent finding sed(1) in a loop meson: improve handling of `sane_tool_path` option meson: improve PATH handling meson: drop separate version library meson: stop linking libcurl into all executables meson: introduce `libgit_curl` dependency meson: simplify use of the common-main library meson: inline the static 'git' library meson: fix OpenSSL fallback when not explicitly required meson: fix exec path with enabled runtime prefix
2025-02-26meson: improve handling of `sane_tool_path` optionPatrick Steinhardt
The `sane_tool_path` option can be used to override the PATH variable from which the build process, tests and ultimately Git will end up picking programs from. It is currently lacking though because we only use it to populate the PATH environment variable for executed scripts and for the `BROKEN_PATH_FIX` mechanism, but we don't use it to find programs used in the build process itself. Fix this issue by treating it similar to the Windows-specific paths, which will make us use it both to find programs and to populate the PATH environment variable. To help with this fix, change the type of the option to be an array of paths, which makes the handling a bit easier for us. It's also the correct thing to do as the input indeed is a list of paths. Furthermore, the option now overrides the default behaviour on Windows, which si to pick up tools from Git for Windows. This is done so that it becomes easier to override that default behaviour in case it's not desired. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18meson: wire up static analysis via CoccinellePatrick Steinhardt
Wire up static analysis via Coccinelle via a new test target "coccicheck". This target can be executed via `meson compile coccicheck` and generates the semantic patch for us. Note that we don't hardcode the list of source and header files that shall be analyzed, and instead use git-ls-files(1) to find them for us. This is because we also want to analyze files that may not get built on the current platform, so finding all sources at configure time is easier than introducing a new variable that tracks all sources, including those which aren't being built. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18meson: wire up git-contacts(1)Patrick Steinhardt
Wire up the build for git-contacts(1) in Meson. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-18meson: wire up credential helpersPatrick Steinhardt
We've got a couple of credential helpers in "contrib/credential", all of which aren't yet wired up via Meson. Do so. Note that ideally, we'd also wire up t0303 to be executed with each of the credential helpers to verify their functionality. Unfortunately though, none of them pass the test suite right now, so this is left for a future change. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-06Merge branch 'ps/zlib-ng'Junio C Hamano
The code paths to interact with zlib has been cleaned up in preparation for building with zlib-ng. * ps/zlib-ng: ci: make "linux-musl" job use zlib-ng ci: switch linux-musl to use Meson compat/zlib: allow use of zlib-ng as backend git-zlib: cast away potential constness of `next_in` pointer compat/zlib: provide stubs for `deflateSetHeader()` compat/zlib: provide `deflateBound()` shim centrally git-compat-util: move include of "compat/zlib.h" into "git-zlib.h" compat: introduce new "zlib.h" header git-compat-util: drop `z_const` define compat: drop `uncompress2()` compatibility shim
2025-02-03Merge branch 'ps/build-meson-fixes'Junio C Hamano
More build fixes and enhancements on meson based build procedure. * ps/build-meson-fixes: ci: wire up Visual Studio build with Meson ci: raise error when Meson generates warnings meson: fix compilation with Visual Studio meson: make the CSPRNG backend configurable meson: wire up fuzzers meson: wire up generation of distribution archive meson: wire up development environments meson: fix dependencies for generated headers meson: populate project version via GIT-VERSION-GEN GIT-VERSION-GEN: allow running without input and output files GIT-VERSION-GEN: simplify computing the dirty marker
2025-02-03Merge branch 'ps/3.0-remote-deprecation'Junio C Hamano
Following the procedure we established to introduce breaking changes for Git 3.0, allow an early opt-in for removing support of $GIT_DIR/branches/ and $GIT_DIR/remotes/ directories to configure remotes. * ps/3.0-remote-deprecation: remote: announce removal of "branches/" and "remotes/" builtin/pack-redundant: remove subcommand with breaking changes ci: repurpose "linux-gcc" job for deprecations ci: merge linux-gcc-default into linux-gcc Makefile: wire up build option for deprecated features
2025-01-30Merge branch 'ps/build-meson-fixes' into ps/build-meson-fixes-0130Junio C Hamano
* ps/build-meson-fixes: ci: wire up Visual Studio build with Meson ci: raise error when Meson generates warnings meson: fix compilation with Visual Studio meson: make the CSPRNG backend configurable meson: wire up fuzzers meson: wire up generation of distribution archive meson: wire up development environments meson: fix dependencies for generated headers meson: populate project version via GIT-VERSION-GEN GIT-VERSION-GEN: allow running without input and output files GIT-VERSION-GEN: simplify computing the dirty marker
2025-01-28ci: switch linux-musl to use MesonPatrick Steinhardt
Switch over the "linux-musl" job to use Meson instead of Makefiles. This is done due to multiple reasons: - It simplifies our CI infrastructure a bit as we don't have to manually specify a couple of build options anymore. - It verifies that Meson detects and sets those build options automatically. - It makes it easier for us to wire up a new CI job using zlib-ng as backend. One platform compatibility that Meson cannot easily detect automatically is the `GIT_TEST_UTF8_LOCALE` variable used in tests. Wire up a build option for it, which we set via a new "MESONFLAGS" environment variable. Note that we also drop the CC variable, which is set to "gcc". We already default to GCC when CC is unset in "ci/lib.sh", so this is not needed. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-28compat/zlib: allow use of zlib-ng as backendPatrick Steinhardt
The zlib-ng library is a hard fork of the old and venerable zlib library. It describes itself as zlib replacement with optimizations for "next generation" systems. As such, it contains several implementations of central algorithms using for example SSE2, AVX2 and other vectorized CPU intrinsics that supposedly speed up in- and deflating data. And indeed, compiling Git against zlib-ng leads to a significant speedup when reading objects. The following benchmark uses git-cat-file(1) with `--batch --batch-all-objects` in the Git repository: Benchmark 1: zlib Time (mean ± σ): 52.085 s ± 0.141 s [User: 51.500 s, System: 0.456 s] Range (min … max): 52.004 s … 52.335 s 5 runs Benchmark 2: zlib-ng Time (mean ± σ): 40.324 s ± 0.134 s [User: 39.731 s, System: 0.490 s] Range (min … max): 40.135 s … 40.484 s 5 runs Summary zlib-ng ran 1.29 ± 0.01 times faster than zlib So we're looking at a ~25% speedup compared to zlib. This is of course an extreme example, as it makes us read through all objects in the repository. But regardless, it should be possible to see some sort of speedup in most commands that end up accessing the object database. The zlib-ng library provides a compatibility layer that makes it a proper drop-in replacement for zlib: nothing needs to change in the build system to support it. Unfortunately though, this mode isn't easy to use on most systems because distributions do not allow you to install zlib-ng in that way, as that would mean that the zlib library would be globally replaced. Instead, many distributions provide a package that installs zlib-ng without the compatibility layer. This version does provide effectively the same APIs like zlib does, but all of the symbols are prefixed with `zng_` to avoid symbol collisions. Implement a new build option that allows us to link against zlib-ng directly. If set, we redefine zlib symbols so that we use the `zng_` prefixed versions thereof provided by that library. Like this, it becomes possible to install both zlib and zlib-ng (without the compat layer) and then pick whichever library one wants to link against for Git. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-28Merge branch 'ps/build-meson-subtree'Junio C Hamano
The meson-driven build is now aware of "git-subtree" housed in contrib/subtree hierarchy. * ps/build-meson-subtree: meson: wire up the git-subtree(1) command meson: introduce build option for contrib contrib/subtree: fix building docs
2025-01-22meson: make the CSPRNG backend configurablePatrick Steinhardt
The CSPRNG backend is not configurable in Meson and isn't quite discoverable, either. Make it configurable and add the actual backend used to the summary. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22meson: wire up fuzzersPatrick Steinhardt
Meson does not yet know to build our fuzzers. Introduce a new build option "fuzzers" and wire up the fuzzers in case it is enabled. Adapt our CI jobs so that they build the fuzzers by default. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22Makefile: wire up build option for deprecated featuresPatrick Steinhardt
With 57ec9254eb (docs: introduce document to announce breaking changes, 2024-06-14), we have introduced a new document that tracks upcoming breaking changes in the Git project. In 2454970930 (BreakingChanges: early adopter option, 2024-10-11) we have amended the document a bit to mention that any introduced breaking changes must be accompanied by logic that allows us to enable the breaking change at compile-time. While we already have two breaking changes lined up, neither of them has such a switch because they predate those instructions. Introduce the proposed `WITH_BREAKING_CHANGES` preprocessor macro and wire it up with both our Makefiles and Meson. This does not yet wire up the build flag for existing deprecations. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-17meson: introduce build option for contribPatrick Steinhardt
We unconditionally wire up building command completion present in the "contrib/" directory. This may or may not be what users want, and we don't provide a way to disable it. Introduce a new "contrib" build option. This option is introduced as an array so that users can manually pick which exact features they want to include from the "contrib" directory. By default, we build and install shell completions, which is a commonly used feature and also the current default. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-16Merge branch 'ps/meson-weak-sha1-build'Junio C Hamano
meson-based build now supports the unsafe-sha1 build knob. * ps/meson-weak-sha1-build: meson: provide a summary of configured backends meson: wire up unsafe SHA1 backend meson: add missing dots for build options meson: simplify conditions for HTTPS and SHA1 dependencies meson: require SecurityFramework when it's used as SHA1 backend meson: deduplicate access to SHA1/SHA256 backend options meson: consistenlty spell 'CommonCrypto'
2025-01-13Merge branch 'ps/meson-weak-sha1-build' into ps/build-meson-fixesJunio C Hamano
* ps/meson-weak-sha1-build: meson: provide a summary of configured backends meson: wire up unsafe SHA1 backend meson: add missing dots for build options meson: simplify conditions for HTTPS and SHA1 dependencies meson: require SecurityFramework when it's used as SHA1 backend meson: deduplicate access to SHA1/SHA256 backend options meson: consistenlty spell 'CommonCrypto'
2024-12-30meson: wire up unsafe SHA1 backendPatrick Steinhardt
In 06c92dafb8 (Makefile: allow specifying a SHA-1 for non-cryptographic uses, 2024-09-26), we have introduced a cryptographically-insecure backend for SHA1 that can optionally be used in some contexts where the processed data is not security relevant. This effort was in-flight with the effort to introduce Meson, so we don't have an equivalent here. Wire up a new build option that lets users pick an unsafe SHA1 backend. Note that for simplicity's sake we have to drop the error condition around an unhandled SHA1 backend. This should be fine though given that Meson verifies the value for combo-options for us. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30meson: add missing dots for build optionsPatrick Steinhardt
Most of our Meson build options end with a trailing dot, but those for our SHA1 and SHA256 backends don't. Add it. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30meson: consistenlty spell 'CommonCrypto'Patrick Steinhardt
The 'CommonCrypto' backend can be specified as HTTPS and SHA1 backends, but the value that one needs to use is inconsistent across those two build options. Unify it to 'CommonCrypto'. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-27meson: wire up support for AsciiDoctorPatrick Steinhardt
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>
2024-12-23Merge branch 'ps/build-hotfix'Junio C Hamano
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
2024-12-20meson: add options to override build informationPatrick Steinhardt
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>
2024-12-20meson: skip gitweb build when Perl is disabledPatrick Steinhardt
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>
2024-12-07Introduce support for the Meson build systemPatrick Steinhardt
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>