New features

Add optimization plain option

The optimization built-in option now accepts plain value, which will not set any optimization flags. This is now the default value of the flag for buildtype=plain, which is useful for distros, that set the optimization and hardening flags by other means.

If you are using the value of get_option('optimization') in your Meson scripts, make sure you are not making assumptions about it, such as that the value can be passed to a compiler in -O flag.

New languages: nasm and masm

When the nasm language is added to the project, .asm files are automatically compiled with NASM. This is only supported for x86 and x86_64 CPU family. yasm is used as fallback if nasm command is not found.

When the masm language is added to the project, .masm files are automatically compiled with Microsoft's Macro Assembler. This is only supported for x86, x86_64, ARM and AARCH64 CPU families.

Note that GNU Assembly files usually have .s or .S extension and were already built using C compiler such as GCC or CLANG.

project('test', 'nasm')

exe = executable('hello', 'hello.asm')
test('hello', exe)

Pager and colors for meson configure output

The output of meson configure, printing all options, is now more readable by automatically using a pager (less by default) and colors. The pager used can be controlled by setting PAGER environment variable, or --no-pager command line option.

various install_* functions no longer handle the sticky bit

It is not possible to portably grant the sticky bit to a file, and where possible, it doesn't do anything. It is not expected that any users are using this functionality.

Variously:

• on Linux, it has no meaningful effect
• on Solaris, attempting to set the permission bit is silently ignored by the OS
• on FreeBSD, attempting to set the permission bit is an error

Attempting to set this permission bit in the install_mode: kwarg to any function other than install_emptydir() will now result in a warning, and the permission bit being ignored.

fs.copyfile to replace configure_file(copy : true)

A new method has been added to the fs module, copyfile. This method replaces configure_file(copy : true), but only copies files. Unlike configure_file() it runs at build time, and the output name is optional defaulting to the filename without paths of the input if unset:

fs.copyfile('src/file.txt')

Will create a file in the current build directory called file.txt

fs.copyfile('file.txt', 'outfile.txt')

Will create a copy renamed to outfile.txt

Added update_mime_database to gnome.post_install()

Applications that install a .xml file containing a mime-type need to update the cache upon installation. Most applications do that using a custom script, but it can now be done by Meson directly.

Added preserve_path arg to install_data

The install_data() function now has an optional argument preserve_path that allows installing multi-directory data file structures that live alongside source code with a single command.

This is also available in the specialized py_installation.install_sources method.

BSD support for the jni dependency

This system dependency now supports all BSD systems that Meson currently supports, including FreeBSD, NetBSD, OpenBSD, and DragonflyBSD.

Credentials from ~/.netrc for https URLs

When a subproject is downloaded using an https:// URL, credentials from ~/.netrc are now used. This avoids hardcoding login and password in plain text in the URL itself.

Basic support for oneAPI compilers on Linux and Windows

To use on Linux:

source /opt/intel/oneapi/setvars.sh
CC=icx CXX=icpx FC=ifx meson setup builddir

New method to preprocess source files

Compiler object has a new preprocess() method. It is supported by all C/C++ compilers. It preprocess sources without compiling them.

The preprocessor will receive the same arguments (include directories, defines, etc) as with normal compilation. That includes for example args added with add_project_arguments(), or on the command line with -Dc_args=-DFOO.

cc = meson.get_compiler('c')
pp_files = cc.preprocess('foo.c', 'bar.c', output: '@PLAINNAME@')
exe = executable('app', pp_files)

python.find_installation() now accepts pure argument

The default value of pure: for py.install_sources() and py.get_install_dir() can now be changed by explicitly passing a pure: kwarg to find_installation().

This can be used to ensure that multiple install_sources() invocations do not forget to specify the kwarg each time.

Generates rust-project.json when there are Rust targets

This is a format similar to compile_commands.json, but specifically used by the official rust LSP, rust-analyzer. It is generated automatically if there are Rust targets, and is placed in the build directory.

summary() accepts disablers

Disabler options can be passed to summary() as the value to be printed.

Option to allow meson test to fail fast after the first failing testcase

meson test --maxfail=1 will now cause all pending or in-progress tests to be canceled or interrupted after 1 test is marked as failing. This can be used for example to quit a CI run and avoid burning additional time as soon as it is known that the overall return status will be failing.

Incremental ThinLTO with b_thinlto_cache

Incremental ThinLTO can now be enabled by passing -Db_thinlto_cache=true during setup. The use of caching speeds up incremental builds significantly while retaining all the runtime performance benefits of ThinLTO.

The cache location defaults to a Meson-managed directory inside the build folder, but can be customized with b_thinlto_cache_dir.

Update all wraps from WrapDB with meson wrap update command

The command meson wrap update, with no extra argument, will now update all wraps that comes from WrapDB to the latest version. The extra --force argument will also replace wraps that do not come from WrapDB if one is available.

The command meson subprojects update will not download new wrap files from WrapDB any more.

Added include_core_only arg to wayland.scan_xml.

The scan_xml function from the wayland module now has an optional bool argument include_core_only, so that headers generated by wayland-scanner now only include wayland-client-core.h instead of wayland-client.h.

Automatic fallback using WrapDB

A new command has been added: meson wrap update-db. It downloads the list of wraps available in WrapDB and stores it locally in subprojects/wrapdb.json. When that file exists and a dependency is not found on the system but is available in WrapDB, Meson will automatically download it.