Merge topic 'try_compile-project-platform-vars'

a6562ff579 try_compile: Add option to skip passing platform variables
4843a37676 try_compile: Propagate platform variables in project-mode too

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !7265

7 files changed, 79 insertions, 0 deletions

diff --git a/Help/command/try_compile.rst b/Help/command/try_compile.rst
index 4b2a631..806a98d 100644
--- a/Help/command/try_compile.rst
+++ b/Help/command/try_compile.rst
@@ -7,6 +7,8 @@ try_compile
 
 Try building some code.
 
+.. _`Try Compiling Whole Projects`:
+
 Try Compiling Whole Projects
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -25,6 +27,15 @@ will not be deleted after this command is run.  Specify ``<targetName>`` to
 build a specific target instead of the ``all`` or ``ALL_BUILD`` target.  See
 below for the meaning of other options.
 
+.. versionchanged:: 3.24
+  CMake variables describing platform settings, and those listed by the
+  :variable:`CMAKE_TRY_COMPILE_PLATFORM_VARIABLES` variable, are propagated
+  into the project's build configuration.  See policy :policy:`CMP0137`.
+  Previously this was only done by the
+  :ref:`source file <Try Compiling Source Files>` signature.
+
+.. _`Try Compiling Source Files`:
+
 Try Compiling Source Files
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -205,3 +216,7 @@ a build configuration.
 .. versionchanged:: 3.14
   For the :generator:`Green Hills MULTI` generator the GHS toolset and target
   system customization cache variables are also propagated into the test project.
+
+.. versionadded:: 3.24
+  The :variable:`CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES` variable may be
+  set to disable passing platform variables into the test project.
diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst
index 259cebb..788d086 100644
--- a/Help/manual/cmake-policies.7.rst
+++ b/Help/manual/cmake-policies.7.rst
@@ -58,6 +58,7 @@ Policies Introduced by CMake 3.24
 .. toctree::
    :maxdepth: 1
 
+   CMP0137: try_compile() passes platform variables in project mode. </policy/CMP0137>
    CMP0136: Watcom runtime library flags are selected by an abstraction. </policy/CMP0136>
    CMP0135: ExternalProject ignores timestamps in archives by default for the URL download method. </policy/CMP0135>
    CMP0134: Fallback to \"HOST\" Windows registry view when \"TARGET\" view is not usable. </policy/CMP0134>
diff --git a/Help/manual/cmake-variables.7.rst b/Help/manual/cmake-variables.7.rst
index 00ea0bc..ff431ad 100644
--- a/Help/manual/cmake-variables.7.rst
+++ b/Help/manual/cmake-variables.7.rst
@@ -503,6 +503,7 @@ Variables that Control the Build
    /variable/CMAKE_STATIC_LINKER_FLAGS_CONFIG_INIT
    /variable/CMAKE_STATIC_LINKER_FLAGS_INIT
    /variable/CMAKE_TRY_COMPILE_CONFIGURATION
+   /variable/CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES
    /variable/CMAKE_TRY_COMPILE_PLATFORM_VARIABLES
    /variable/CMAKE_TRY_COMPILE_TARGET_TYPE
    /variable/CMAKE_UNITY_BUILD
diff --git a/Help/policy/CMP0137.rst b/Help/policy/CMP0137.rst
new file mode 100644
index 0000000..ba3cb9c
--- /dev/null
+++ b/Help/policy/CMP0137.rst
@@ -0,0 +1,33 @@
+CMP0137
+-------
+
+.. versionadded:: 3.24
+
+:command:`try_compile` passes platform variables in project mode.
+
+The :command:`try_compile` command :ref:`source file <Try Compiling Source
+Files>` signature propagates CMake variables containing platform settings,
+and those specified by the :variable:`CMAKE_TRY_COMPILE_PLATFORM_VARIABLES`
+variable, into the generated test project.  This helps the test project drive
+the toolchain the same way the calling project will.  In CMake 3.23 and below,
+the :ref:`whole-project <Try Compiling Whole Projects>` signature does not
+propagate platform variables automatically.  CMake 3.24 and above prefer to
+propagate platform variables in the :ref:`whole-project <Try Compiling Whole
+Projects>` signature.  This policy provides compatibility with projects that
+have not been updated to expect the behavior.
+
+The ``OLD`` behavior for this policy is to not pass any additional variables to
+the :ref:`whole-project <Try Compiling Whole Projects>` signature.
+The ``NEW`` behavior for this policy is to pass the same variables that the
+:ref:`source file <Try Compiling Source Files>` signature does.
+
+Regardless of the policy setting, the
+:variable:`CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES` variable may be set
+to suppress passing the platform variables through either signature.
+
+This policy was introduced in CMake version 3.24.  Use the
+:command:`cmake_policy` command to set this policy to ``OLD`` or ``NEW``
+explicitly. Unlike many policies, CMake version |release| does *not* warn
+by default when this policy is not set and simply uses ``OLD`` behavior.
+
+.. include:: DEPRECATED.txt
diff --git a/Help/release/dev/try_compile-project-platform-vars.rst b/Help/release/dev/try_compile-project-platform-vars.rst
new file mode 100644
index 0000000..06596d4
--- /dev/null
+++ b/Help/release/dev/try_compile-project-platform-vars.rst
@@ -0,0 +1,10 @@
+try_compile-project-platform-vars
+---------------------------------
+
+* The :command:`try_compile` command
+  :ref:`whole-project <Try Compiling Whole Projects>` signature
+  now propagates platform variables.  See policy :policy:`CMP0137`.
+
+* The :variable:`CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES` variable
+  was added to tell the :command:`try_compile` command not to
+  pass any platform variables to the test project.
diff --git a/Help/variable/CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES.rst b/Help/variable/CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES.rst
new file mode 100644
index 0000000..944caa5
--- /dev/null
+++ b/Help/variable/CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES.rst
@@ -0,0 +1,10 @@
+CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES
+---------------------------------------
+
+Set to a true value to tell the :command:`try_compile` command not
+to propagate any platform variables into the test project.
+
+The :command:`try_compile` command normally passes some CMake variables
+that configure the platform and toolchain behavior into test projects.
+See policy :policy:`CMP0137`.  This variable may be set to disable
+that behavior.
diff --git a/Help/variable/CMAKE_TRY_COMPILE_PLATFORM_VARIABLES.rst b/Help/variable/CMAKE_TRY_COMPILE_PLATFORM_VARIABLES.rst
index d178513..6b26d14 100644
--- a/Help/variable/CMAKE_TRY_COMPILE_PLATFORM_VARIABLES.rst
+++ b/Help/variable/CMAKE_TRY_COMPILE_PLATFORM_VARIABLES.rst
@@ -26,3 +26,12 @@ If a user passes ``-DMY_CUSTOM_VARIABLE=SomeValue`` to CMake then this
 setting will be made visible to the toolchain file both for the main
 project and for test projects generated by the :command:`try_compile`
 command source file signature.
+
+.. versionchanged:: 3.24
+  Listed variables are propagated to the :command:`try_compile`
+  :ref:`whole-project <Try Compiling Whole Projects>` signature too.
+  See :policy:`CMP0137`.
+
+.. versionadded:: 3.24
+  The :variable:`CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES` variable may be
+  set to disable passing platform variables into the test project.