IDE integration

Meson has exporters for Visual Studio and XCode, but writing a custom backend for every IDE out there is not a scalable approach. To solve this problem, Meson provides an API that makes it easy for any IDE or build tools to integrate Meson builds and provide an experience comparable to a solution native to the IDE.

All the resources required for such a IDE integration can be found in the meson-info directory in the build directory.

The first thing to do when setting up a Meson project in an IDE is to select the source and build directories. For this example we assume that the source resides in an Eclipse-like directory called workspace/project and the build tree is nested inside it as workspace/project/build. First, we initialize Meson by running the following command in the source directory.

meson builddir

With this command meson will configure the project and also generate introspection information that is stored in intro-*.json files in the meson-info directory. The introspection dump will be automatically updated when meson is (re)configured, or the build options change. Thus, an IDE can watch for changes in this directory to know when something changed.

The meson-info directory should contain the following files:

File | Description ------------------------------- | --------------------------------------------------------------------- intro-benchmarks.json | Lists all benchmarks intro-buildoptions.json | Contains a full list of meson configuration options for the project intro-buildsystem_files.json | Full list of all meson build files intro-dependencies.json | Lists all dependencies used in the project intro-installed.json | Contains mapping of files to their installed location intro-projectinfo.json | Stores basic information about the project (name, version, etc.) intro-targets.json | Full list of all build targets intro-tests.json | Lists all tests with instructions how to run them

The content of the JSON files is further specified in the remainder of this document.

The targets section

The most important file for an IDE is probably intro-targets.json. Here each target with its sources and compiler parameters is specified. The JSON format for one target is defined as follows:

{
    "name": "Name of the target",
    "id": "The internal ID meson uses",
    "type": "<TYPE>",
    "filename": ["list", "of", "generated", "files"],
    "build_by_default": true / false,
    "target_sources": [],
    "installed": true / false,
}

If the key installed is set to true, the key install_filename will also be present. It stores the installation location for each file in filename. If one file in filename is not installed, its corresponding install location is set to null.

A target usually generates only one file. However, it is possible for custom targets to have multiple outputs.

Target sources

The intro-targets.json file also stores a list of all source objects of the target in the target_sources. With this information, an IDE can provide code completion for all source files.

{
    "language": "language ID",
    "compiler": ["The", "compiler", "command"],
    "parameters": ["list", "of", "compiler", "parameters"],
    "sources": ["list", "of", "all", "source", "files", "for", "this", "language"],
    "generated_sources": ["list", "of", "all", "source", "files", "that", "where", "generated", "somewhere", "else"]
}

It should be noted that the compiler parameters stored in the parameters differ from the actual parameters used to compile the file. This is because the parameters are optimized for the usage in an IDE to provide autocompletion support, etc. It is thus not recommended to use this introspection information for actual compilation.

Possible values for type

The following table shows all valid types for a target.

value of type | Description ---------------- | ------------------------------------------------------------------------------------------------- executable | This target will generate an executable file static library | Target for a static library shared library | Target for a shared library shared module | A shared library that is meant to be used with dlopen rather than linking into something else custom | A custom target run | A Meson run target jar | A Java JAR target

Build Options

The list of all build options (build type, warning level, etc.) is stored in the intro-buildoptions.json file. Here is the JSON format for each option.

{
    "name": "name of the option",
    "description": "the description",
    "type": "type ID",
    "value": "value depends on type",
    "section": "section ID"
}

The supported types are:

  • string
  • boolean
  • combo
  • integer
  • array

For the type combo the key choices is also present. Here all valid values for the option are stored.

The possible values for section are:

  • core
  • backend
  • base
  • compiler
  • directory
  • user
  • test

To set the options, use the meson configure command.

Since Meson 0.50.0 it is also possible to get the default buildoptions without a build directory by providing the root meson.build instead of a build directory to meson introspect --buildoptions.

Running --buildoptions without a build directory produces the same output as running it with a freshly configured build directory.

However, this behavior is not guaranteed if subprojects are present. Due to internal limitations all subprojects are processed even if they are never used in a real meson run. Because of this options for the subprojects can differ.

Tests

Compilation and unit tests are done as usual by running the ninja and ninja test commands. A JSON formatted result log can be found in workspace/project/builddir/meson-logs/testlog.json.

When these tests fail, the user probably wants to run the failing test in a debugger. To make this as integrated as possible, extract the tests from the intro-tests.json and intro-benchmarks.json files. This provides you with all the information needed to run the test: what command to execute, command line arguments and environment variable settings.

{
    "name": "name of the test",
    "workdir": "the working directory (can be null)",
    "timeout": "the test timeout",
    "suite": ["list", "of", "test", "suites"],
    "is_parallel": true / false,
    "cmd": ["command", "to", "run"],
    "env": {
        "VARIABLE1": "value 1",
        "VARIABLE2": "value 2"
    }
}

Programmatic interface

Meson also provides the meson introspect for project introspection via the command line. Use meson introspect -h to see all available options.

This API can also work without a build directory for the --projectinfo command.

Existing integrations

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