Help: Add presets documentation and release notes

3 files changed, 378 insertions, 0 deletions

diff --git a/Help/manual/cmake-gui.1.rst b/Help/manual/cmake-gui.1.rst
index ff8311b..d9c8ed7 100644
--- a/Help/manual/cmake-gui.1.rst
+++ b/Help/manual/cmake-gui.1.rst
@@ -11,6 +11,7 @@ Synopsis
  cmake-gui [<options>]
  cmake-gui [<options>] {<path-to-source> | <path-to-existing-build>}
  cmake-gui [<options>] -S <path-to-source> -B <path-to-build>
+ cmake-gui [<options>] -S <path-to-source> --preset=<preset-name>
 
 Description
 ===========
@@ -36,6 +37,10 @@ Options
 
  If the directory doesn't already exist CMake will make it.
 
+``--preset=<preset-name>``
+ Name of the preset to use from the project's ``CMakePresets.json`` file, if it
+ has one.
+
 .. include:: OPTIONS_HELP.txt
 
 See Also
diff --git a/Help/manual/cmake.1.rst b/Help/manual/cmake.1.rst
index 9850116..764f61e 100644
--- a/Help/manual/cmake.1.rst
+++ b/Help/manual/cmake.1.rst
@@ -12,6 +12,7 @@ Synopsis
   cmake [<options>] <path-to-source>
   cmake [<options>] <path-to-existing-build>
   cmake [<options>] -S <path-to-source> -B <path-to-build>
+  cmake [<options>] -S <path-to-source> --preset=<preset-name>
 
  `Build a Project`_
   cmake --build <dir> [<options>] [-- <build-tool-options>]
@@ -148,6 +149,368 @@ source and build trees and generate a buildsystem:
 
     $ cmake -S src -B build
 
+``cmake [<options>] -S <path-to-source> --preset=<preset-name>``
+  Uses ``<path-to-source>`` as the source tree and reads a preset from
+  ``<path-to-source>/CMakePresets.json`` and
+  ``<path-to-source>/CMakeUserPresets.json``. The preset specifies the
+  generator and the build directory, and optionally a list of variables and
+  other arguments to pass to CMake. The :manual:`CMake GUI <cmake-gui(1)>` can
+  also recognize ``CMakePresets.json`` and ``CMakeUserPresets.json`` files.
+
+  ``CMakePresets.json`` and ``CMakeUserPresets.json`` have exactly the same
+  format, and both are optional (though at least one must be present if
+  ``--preset`` is specified.) ``CMakePresets.json`` is meant to save
+  project-wide builds, while ``CMakeUserPresets.json`` is meant for developers
+  to save their own local builds. ``CMakePresets.json`` may be checked into a
+  version control system, and ``CMakeUserPresets.json`` should NOT be checked
+  in. For example, if a project is using Git, ``CMakePresets.json`` may be
+  tracked, and ``CMakeUserPresets.json`` should be added to the ``.gitignore``.
+
+  The presets are read before all other command line options. The options
+  specified by the preset (variables, generator, etc.) can all be overridden by
+  manually specifying them on the command line. For example, if the preset sets
+  a variable called ``MYVAR`` to ``1``, but the user sets it to ``2`` with a
+  ``-D`` argument, the value ``2`` is preferred.
+
+  The files are a JSON document with an object as the root:
+
+  .. code-block:: json
+
+    {
+      "version": 1,
+      "cmakeMinimumRequired": {
+        "major": 3,
+        "minor": 19,
+        "patch": 0
+      },
+      "configurePresets": [
+        {
+          "name": "default",
+          "displayName": "Default Config",
+          "description": "Default build using Ninja generator",
+          "generator": "Ninja",
+          "binaryDir": "${sourceDir}/build/default",
+          "cacheVariables": [
+            {
+              "name": "MY_CACHE_VARIABLE",
+              "type": "BOOL",
+              "value": "OFF"
+            }
+          ]
+        }
+      ]
+    }
+
+  The root object recognizes the following fields:
+
+  ``version``
+
+    A required integer representing the version of the JSON schema. Currently,
+    the only supported version is 1.
+
+  ``cmakeMinimumRequired``
+
+    An optional object representing the minimum version of CMake needed to
+    build this project. This object consists of the following fields:
+
+    ``major``
+
+      An optional integer representing the major version.
+
+    ``minor``
+
+      An optional integer representing the minor version.
+
+    ``patch``
+
+      An optional integer representing the patch version.
+
+  ``vendor``
+
+    An optional map containing vendor-specific information. CMake does not
+    interpret the contents of this field except to verify that it is a map if
+    it does exist. However, the keys should be a vendor-specific domain name
+    followed by a ``/``-separated path. For example, the Example IDE 1.0 could
+    use ``example.com/ExampleIDE/1.0``. The value of each field can be anything
+    desired by the vendor, though will typically be a map. For example:
+
+    .. code-block:: json
+
+      {
+        "version": 1,
+        "vendor": {
+          "example.com/ExampleIDE/1.0": {
+            "autoFormat": true
+          }
+        },
+        "configurePresets": []
+      }
+
+  ``configurePresets``
+
+    An optional array of configure preset objects. Each preset may contain the
+    following fields:
+
+    ``name``
+
+      A required string representing the machine-friendly name of the preset.
+      This identifier is used in the ``--preset`` argument. There must not be
+      two presets in the union of ``CMakePresets.json`` and
+      ``CMakeUserPresets.json`` in the same directory with the same name.
+
+    ``hidden``
+
+      An optional boolean specifying whether or not a preset should be hidden.
+      If a preset is hidden, it cannot be used in the ``--preset=`` argument,
+      will not show up in the :manual:`CMake GUI <cmake-gui(1)>`, and does not
+      have to have a valid ``generator`` or ``binaryDir``, even from
+      inheritance. ``hidden`` presets are intended to be used as a base for
+      other presets to inherit via the ``inherits`` field.
+
+    ``inherits``
+
+      An optional array of strings representing the names of presets to inherit
+      from. The preset will inherit all of the fields from the ``inherits``
+      presets by default (except ``name``, ``hidden``, ``inherits``,
+      ``description``, and ``longDescription``), but can override them as
+      desired. If multiple ``inherits`` presets provide conflicting values for
+      the same field, the earlier preset in the ``inherits`` list will be
+      preferred. Presets in ``CMakePresets.json`` may not inherit from presets
+      in ``CMakeUserPresets.json``.
+
+      This field can also be a string, which is equivalent to an array
+      containing one string.
+
+    ``vendor``
+
+      An optional map containing vendor-specific information. CMake does not
+      interpret the contents of this field except to verify that it is a map
+      if it does exist. However, it should follow the same conventions as the
+      root-level ``vendor`` field. If vendors use their own per-preset
+      ``vendor`` field, they should implement inheritance in a sensible manner
+      when appropriate.
+
+    ``displayName``
+
+      An optional string with a human-friendly name of the preset.
+
+    ``description``
+
+      An optional string with a human-friendly description of the preset.
+
+    ``generator``
+
+      An optional string representing the generator to use for the preset. If
+      ``generator`` is not specified, it must be inherited from the
+      ``inherits`` preset (unless this preset is ``hidden``).
+
+      Note that for Visual Studio generators, unlike in the command line ``-G``
+      argument, you cannot include the platform name in the generator name. Use
+      the ``architecture`` field instead.
+
+    ``architecture``
+
+      An optional string representing the platform name to use for Visual
+      Studio generators.
+
+    ``toolset``
+
+      An optional string representing the toolset name to use for Visual Studio
+      generators.
+
+    ``cmakeGeneratorConfig``
+
+      An optional string telling CMake how to handle the ``architecture`` and
+      ``toolset`` fields. Valid values are:
+
+      ``"default"``
+
+        Set the platform and toolset using the ``architecture`` and ``toolset``
+        fields respectively. On non-Visual Studio generators, this will result
+        in an error if ``architecture`` or ``toolset`` are set.
+
+      ``"ignore"``
+
+        Do not set the platform or toolset at all, even on Visual Studio
+        generators. This is useful if, for example, a preset uses the Ninja
+        generator, and an IDE knows how to set up the Visual C++ environment
+        from the ``architecture`` and ``toolset`` fields. In that case, CMake
+        will ignore ``architecture`` and ``toolset``, but the IDE can use them
+        to set up the environment before invoking CMake.
+
+    ``binaryDir``
+
+      An optional string representing the path to the output binary directory.
+      This field supports macro expansion. If a relative path is specified, it
+      is calculated relative to the source directory. If ``binaryDir`` is not
+      specified, it must be inherited from the ``inherits`` preset (unless this
+      preset is ``hidden``).
+
+    ``cmakeExecutable``
+
+      An optional string representing the path to the CMake executable to use
+      for this preset. This is reserved for use by IDEs, and is not used by
+      CMake itself. IDEs that use this field should expand any macros in it.
+
+    ``cacheVariables``
+
+      An optional map of cache variables. The key is the variable name, and the
+      value is either ``null``, a string representing the value of the variable
+      (which supports macro expansion), or an object with the following fields:
+
+      ``type``
+
+        An optional string representing the type of the variable.
+
+      ``value``
+
+        A required string representing the value of the variable. This field
+        supports macro expansion.
+
+      Cache variables are inherited through the ``inherits`` field, and the
+      preset's variables will be the union of its own ``cacheVariables`` and
+      the ``cacheVariables`` from all its parents. If multiple presets in this
+      union define the same variable, the standard rules of ``inherits`` are
+      applied. Setting a variable to ``null`` causes it to not be set, even if
+      a value was inherited from another preset.
+
+    ``environment``
+
+      An optional map of environment variables. The key is the variable name,
+      and the value is either ``null`` or a string representing the value of
+      the variable. Each variable is set regardless of whether or not a value
+      was given to it by the process's environment. This field supports macro
+      expansion, and environment variables in this map may reference each
+      other, and may be listed in any order, as long as such references do not
+      cause a cycle (for example, if ``ENV_1`` is ``$env{ENV_2}``, ``ENV_2``
+      may not be ``$env{ENV_1}``.)
+
+      Environment variables are inherited through the ``inherits`` field, and
+      the preset's environment will be the union of its own ``environment`` and
+      the ``environment`` from all its parents. If multiple presets in this
+      union define the same variable, the standard rules of ``inherits`` are
+      applied. Setting a variable to ``null`` causes it to not be set, even if
+      a value was inherited from another preset.
+
+    ``warnings``
+
+      An optional object specifying warnings. The object may contain the
+      following fields:
+
+      ``dev``
+
+        An optional boolean. Equivalent to passing ``-Wdev`` or ``-Wno-dev``
+        on the command line. This may not be set to ``false`` if ``errors.dev``
+        is set to ``true``.
+
+      ``deprecated``
+
+        An optional boolean. Equivalent to passing ``-Wdeprecated`` or
+        ``-Wno-deprecated`` on the command line. This may not be set to
+        ``false`` if ``errors.deprecated`` is set to ``true``.
+
+      ``uninitialized``
+
+        An optional boolean. Setting this to ``true`` is equivalent to passing
+        ``--warn-uninitialized`` on the command line.
+
+      ``unusedVars``
+
+        An optional boolean. Setting this to ``false`` is equivalent to passing
+        ``--no-warn-unused-cli`` on the command line.
+
+      ``systemVars``
+
+        An optional boolean. Setting this to ``true`` is equivalent to passing
+        ``--check-system-vars`` on the command line.
+
+    ``errors``
+
+      An optional object specifying errors. The object may contain the
+      following fields:
+
+      ``dev``
+
+        An optional boolean. Equivalent to passing ``-Werror=dev`` or
+        ``-Wno-error=dev`` on the command line. This may not be set to ``true``
+        if ``warnings.dev`` is set to ``false``.
+
+      ``deprecated``
+
+        An optional boolean. Equivalent to passing ``-Werror=deprecated`` or
+        ``-Wno-error=deprecated`` on the command line. This may not be set to
+        ``true`` if ``warnings.deprecated`` is set to ``false``.
+
+  As mentioned above, some fields support macro expansion. Macros are
+  recognized in the form ``$<macro-namespace>{<macro-name>}``. All macros are
+  evaluated in the context of the preset being used, even if the macro is in a
+  field that was inherited from another preset. For example, if the ``Base``
+  preset sets variable ``PRESET_NAME`` to ``${presetName}``, and the
+  ``Derived`` preset inherits from ``Base``, ``PRESET_NAME`` will be set to
+  ``Derived``.
+
+  It is an error to not put a closing brace at the end of a macro name. For
+  example, ``${sourceDir`` is invalid. A dollar sign (``$``) followed by
+  anything other than a left curly brace (``{``) with a possible namespace is
+  interpreted as a literal dollar sign.
+
+  Recognized macros include:
+
+  ``${sourceDir}``
+
+    Path to the project source directory.
+
+  ``${sourceParentDir}``
+
+    Path to the project source directory's parent directory.
+
+  ``${presetName}``
+
+    Name specified in the preset's ``name`` field.
+
+  ``${generator}``
+
+    Generator specified in the preset's ``generator`` field.
+
+  ``${dollar}``
+
+    A literal dollar sign (``$``).
+
+  ``$env{<variable-name>}``
+
+    Environment variable with name ``<variable-name>``. If the variable is
+    defined in the ``environment`` field, that value is used instead of the
+    value from the parent environment. If the environment variable is not
+    defined, this evaluates as an empty string.
+
+    Note that while Windows environment variable names are case-insensitive,
+    variable names within a preset are still case-sensitive. This may lead to
+    unexpected results when using inconsistent casing. For best results, keep
+    the casing of environment variable names consistent.
+
+  ``$penv{<variable-name>}``
+
+    Similar to ``$env{<variable-name>}``, except that the value only comes from
+    the parent environment, and never from the ``environment`` field. This
+    allows you to prepend or append values to existing environment variables.
+    For example, setting ``PATH`` to ``/path/to/ninja/bin:$penv{PATH}`` will
+    prepend ``/path/to/ninja/bin`` to the ``PATH`` environment variable. This
+    is needed because ``$env{<variable-name>}`` does not allow circular
+    references.
+
+  ``$vendor{<macro-name>}``
+
+    An extension point for vendors to insert their own macros. CMake will not
+    be able to use presets which have a ``$vendor{<macro-name>}`` macro, and
+    effectively ignores such presets. However, it will still be able to use
+    other presets from the same file.
+
+    CMake does not make any attempt to interpret ``$vendor{<macro-name>}``
+    macros. However, to avoid name collisions, IDE vendors should prefix
+    ``<macro-name>`` with a very short (preferably <= 4 characters) vendor
+    identifier prefix, followed by a ``.``, followed by the macro name. For
+    example, the Example IDE could have ``$vendor{xide.ideInstallDir}``.
+
 In all cases the ``<options>`` may be zero or more of the `Options`_ below.
 
 After generating a buildsystem one may use the corresponding native
@@ -813,6 +1176,11 @@ with one of the following options:
 
 .. include:: OPTIONS_HELP.txt
 
+To view the presets available for a project, use
+
+.. code-block::shell
+
+  cmake <source-dir> --list-presets
 
 See Also
 ========
diff --git a/Help/release/dev/cmake-presets.rst b/Help/release/dev/cmake-presets.rst
new file mode 100644
index 0000000..a901f10
--- /dev/null
+++ b/Help/release/dev/cmake-presets.rst
@@ -0,0 +1,5 @@
+cmake-presets
+-------------
+
+* :manual:`cmake(1)` and :manual:`cmake-gui(1)` now recognize
+  ``CMakePresets.json`` and ``CMakeUserPresets.json`` files.