New features (in development)

Custom dependency for atomic now works on MSVC

dependency('atomic') now works on MSVC >=19.35.32124. It requires c_std=c11 or later, otherwise the dependency will return not found.

Support for CACHEDIR.TAG specification

A CACHEDIR.TAG file (https://bford.info/cachedir/) is now created in the build directory as part of the setup and regenerate phases, allowing backup software to ignore the whole directory.

New "clippy-json" Ninja Target For rust-analyzer

A new clippy-json ninja target will now be generated for rust projects.

rust-analyzer supports non-cargo based projects so long as you provide it with a rust-project.json file and a custom "check command" to provide compiler errors. Meson already for some time has generated a rust-project.json file for rust-analyzer, but had no way to hook up its rustc/clippy output to rust-analyzer.

To use the new feature, you need to override the rust-analyzer check command as shown in the rust-analyzer documentation, and set it to a ninja invocation along the lines ofninja clippy-json -C build`.

Delay install script errors to install time

Previously, gnome.post_install might've caused a configure to fail due to tools such as update-desktop-database not being installed or due to an exe_wrapper missing when cross-building glib. Those errors will now be delayed to install time, or not emitted at all if installing with DESTDIR set, since then they'll be skipped.

find_program() now respects --force-fallback-for

If a subproject listed in --force-fallback-for provides a particular program (via program_names in its wrapfile), find_program will use the program from the subproject instead of looking it up from the system.

fs.copyfile() now has a build_subdir argument

fs.copyfile()'s new build_subdir argument allows creating a file inside a subdirectory of the current build directory.

Added depends kwarg to generator.process()

The generator.process() method now supports specifying depends as a kwarg to extend the list of dependencies for generated files.

Added msgfmt_args arg to i18n.gettext

i18n.gettext now supports the msgfmt_args argument. This argument can be used to pass additional arguments to msgfmt when building the translations.

i18n = import('i18n')
i18n.gettext('mycatalog',
             args : ['-k_', '-kN_'],
             msgfmt_args : ['--use-fuzzy'])

include_directories object now have a to_list() method

The inc object returned by include_directories() now has a to_list() method that returns a list of strings of absolute paths. Unless the include path is a system path, there will be a path for the source root and one for the build root.

inc = include_directories('include')
include_paths = inc.to_list()

Added integer base conversions to str.to_int() and int.to_string()

Meson strings can now be converted from hexadecimal, octal, and binary integer literals with str.to_int(). Integers can also be formatted back to strings in those bases with int.to_string(format:).

assert('0xff'.to_int() == 255)
assert(255.to_string(format: 'hex') == '0xff')

Multiple positional arguments for meson wrap install

Previously meson wrap install only accepted a single wrap name to install. This limitation has now been lifted, and it is now possible to specify multiple wrap names for installation. The exit code will be non-zero if any of the wraps fail to install.

meson format allows --recursive with --check-diff

Previously, the --recursive option to meson format required either --inplace or --output. With this version, --check-diff is allowed to.

New option --subprojects for meson format

A new option --subprojects, to be specified together with --recursive, tells meson format to also recurse into subprojects.

OpenHarmony (OHOS) is now recognized as an Android subsystem

Meson now recognizes OpenHarmony / HarmonyOS (OHOS). OHOS behaves like Android -- applications are shared libraries, shared libraries are not versioned, and so on -- but uses musl instead of Bionic. It is therefore modelled as an Android subsystem rather than a separate system.

Machine files select it in the [host_machine] section with:

[host_machine]
system = 'android'
subsystem = 'ohos'

With this, host_machine.system() is 'android' (so all Android handling applies, including unversioned libfoo.so output) while host_machine.subsystem() is 'ohos'. When cross-compiling a CMake subproject, the toolchain file generated by the CMake module sets CMAKE_SYSTEM_NAME = OHOS.

Support for Python 3.7, 3.8, and 3.9 dropped

Meson 1.12 is the first version to require Python version 3.10 or greater.

Support for older versions of Python is maintained with bug fixes only for some LTS releases. See the FAQ entry for more information.

More types of generated files allowed by qt.preprocess

qt.preprocess now allows custom target indexes or generators in addition to custom targets for ui_files, moc_sources and moc_headers.

Non-default members of Cargo workspaces can now be built

The new keyword argument extra_members to the workspace() method allows configuring non-default members of a Cargo workspace. Previously, non-default members were never used for dependency resolution and could not be built.

subproject() and meson.override_find_program() now support the native keyword argument

Subprojects may now be built for the host or build machine (or both). Therefore, in a cross compile setup, build-time dependencies can be built for the machine running the build. When a subproject is run for the build machine it will act just like a normal build == host setup, except that no targets will be installed.

This necessarily means that meson.override_find_program() must differentiate between programs for the host and those for the build machine, as you may need two versions of the same program, which have different outputs based on the machine they are for. For backwards compatibility reasons the default is for the host machine. Inside a native subproject the host and build machine will both be the build machine.

Cargo workspaces use this feature automatically when building procedural macro crates and their dependencies.

meson test now accepts --exclude

meson test has a new --exclude argument to allow skipping named tests. It takes a full test name and can be specified repeatedly. This should help distributions that need to skip tests irrelevant for them or known to be buggy.

werror=true now applies to the linker as well

When werror=true is set, Meson now passes the appropriate fatal-warnings flag to the linker (for example --fatal-warnings for GNU ld, -fatal_warnings for Apple ld, /WX for MSVC link). Previously, werror=true only affected compiler warnings.

Added win_subsystem to shared_library() and shared_module()

Synonym for the one found in executable().

Mostly useful for setting the subsystem version in PE headers. This can affects Windows's ShimEngine, but not SxS lookups. Usually you still want to provide a manifest when targeting modern Windows. Sometime also useful for targeting other subsystems.

Visual Studio backends now also properly supports setting subsystem versions.

i18n.xgettext recursive option now includes "private" dependencies

Suppose we have:

libA.dll -> libB.dll -> libC.dll

Here, libA links with libB, and libB links with libC, but libA does not link with libC directly. So, libC is a "private" dependency of libB. If we collect strings to translate using:

i18n.xgettext(libC)
i18n.xgettext(libB)
pot_file = i18n.xgettext(libA, recursive: true)

Previously, strings from libC would not be included in pot_file, since libC is not a direct link dependency of libA. This has been fixed: when the recursive: true option is used, xgettext now recursively includes translations from all dependencies, including those of dependencies. This is more logical, as even if libA does not directly link with libC, it may still need translated strings from libC.