CMakeDependentOption: Introduce policy CMP0127 for full Condition Syntax

Fixes: #22303

1 files changed, 42 insertions, 19 deletions

diff --git a/Modules/CMakeDependentOption.cmake b/Modules/CMakeDependentOption.cmake
index 96855d2..b7c478f 100644
--- a/Modules/CMakeDependentOption.cmake
+++ b/Modules/CMakeDependentOption.cmake
@@ -10,44 +10,62 @@ Macro to provide an option dependent on other options.
 This macro presents an option to the user only if a set of other
 conditions are true.
 
-Usage:
+.. command:: cmake_dependent_option
 
-.. code-block:: cmake
+  .. code-block:: cmake
 
-  cmake_dependent_option(<option> "<help_text>" <value> <depends> <force>)
+    cmake_dependent_option(<option> "<help_text>" <value> <depends> <force>)
 
-Where ``<option>`` is available to the user if ``<depends>`` is true. When
-``<option>`` is available, the given ``<help_text>`` and initial ``<value>``
-are used. If the ``<depends>`` condition is not true, ``<option>`` will not be
-presented and will always have the value given by ``<force>``. Any value set by
-the user is preserved for when the option is presented again. Each element in
-the fourth parameter is evaluated as an if-condition, so
-:ref:`Condition Syntax` can be used.
+  Makes ``<option>`` available to the user if ``<depends>`` is true. When
+  ``<option>`` is available, the given ``<help_text>`` and initial ``<value>``
+  are used. If the ``<depends>`` condition is not true, ``<option>`` will not be
+  presented and will always have the value given by ``<force>``. Any value set by
+  the user is preserved for when the option is presented again. In case ``<depends>``
+  is a :ref:`semicolon-separated list <CMake Language Lists>`, all elements must
+  be true in order to initialize ``<option>`` with ``<value>``.
 
 Example invocation:
 
 .. code-block:: cmake
 
-  cmake_dependent_option(USE_FOO "Use Foo" ON
-                         "USE_BAR;NOT USE_ZOT" OFF)
+  cmake_dependent_option(USE_FOO "Use Foo" ON "USE_BAR;NOT USE_ZOT" OFF)
 
 If ``USE_BAR`` is true and ``USE_ZOT`` is false, this provides an option called
 ``USE_FOO`` that defaults to ON. Otherwise, it sets ``USE_FOO`` to OFF and
 hides the option from the user. If the status of ``USE_BAR`` or ``USE_ZOT``
 ever changes, any value for the ``USE_FOO`` option is saved so that when the
 option is re-enabled it retains its old value.
+
+.. versionadded:: 3.22
+
+  Full :ref:`Condition Syntax` is now supported.  See policy :policy:`CMP0127`.
+
 #]=======================================================================]
 
 macro(CMAKE_DEPENDENT_OPTION option doc default depends force)
+  cmake_policy(GET CMP0127 _CDO_CMP0127
+    PARENT_SCOPE # undocumented, do not use outside of CMake
+    )
   if(${option}_ISSET MATCHES "^${option}_ISSET$")
     set(${option}_AVAILABLE 1)
-    foreach(d ${depends})
-      string(REGEX REPLACE " +" ";" CMAKE_DEPENDENT_OPTION_DEP "${d}")
-      if(${CMAKE_DEPENDENT_OPTION_DEP})
-      else()
-        set(${option}_AVAILABLE 0)
-      endif()
-    endforeach()
+    if("x${_CDO_CMP0127}x" STREQUAL "xNEWx")
+      foreach(d ${depends})
+        cmake_language(EVAL CODE "
+          if (${d})
+          else()
+            set(${option}_AVAILABLE 0)
+          endif()"
+        )
+      endforeach()
+    else()
+      foreach(d ${depends})
+        string(REGEX REPLACE " +" ";" CMAKE_DEPENDENT_OPTION_DEP "${d}")
+        if(${CMAKE_DEPENDENT_OPTION_DEP})
+        else()
+          set(${option}_AVAILABLE 0)
+        endif()
+      endforeach()
+    endif()
     if(${option}_AVAILABLE)
       option(${option} "${doc}" "${default}")
       set(${option} "${${option}}" CACHE BOOL "${doc}" FORCE)
@@ -61,4 +79,9 @@ macro(CMAKE_DEPENDENT_OPTION option doc default depends force)
   else()
     set(${option} "${${option}_ISSET}")
   endif()
+  if("x${_CDO_CMP0127}x" STREQUAL "xx" AND "x${depends}x" MATCHES "[^A-Za-z0-9_; ]")
+    cmake_policy(GET_WARNING CMP0127 _CDO_CMP0127_WARNING)
+    message(AUTHOR_WARNING "${_CDO_CMP0127_WARNING}")
+  endif()
+  unset(_CDO_CMP0127)
 endmacro()