Merge topic 'save-restore-PACKAGE_PREFIX_DIR'

41f4e1c457 CMakePackageConfigHelpers: Document PACKAGE_PREFIX_DIR for public use
c5231ba29e find_package: Save/restore PACKAGE_PREFIX_DIR
8ac7958e3a generate_apple_*_selection_file: Save/restore PACKAGE_PREFIX_DIR
bf88879f1f generate_apple_architecture_selection_file: Avoid early returns
a4ac2c92f4 Help: Add missing section heading for apple architecture selection
b7fcc44be9 Help: Fix CMakePackageConfigHelpers typos, grammar and formatting
f1cacaa830 Tests/RunCMake/CMakePackage: Define variable closer to where it is used

Acked-by: Kitware Robot <[email protected]>
Merge-request: !9430

Modules/CMakePackageConfigHelpers.cmake

@@ -5,7 +5,7 @@
 CMakePackageConfigHelpers
 -------------------------
 
-Helpers functions for creating config files that can be included by other
+Helper functions for creating config files that can be included by other
 projects to find and use a package.
 
 Generating a Package Configuration File
@@ -26,11 +26,11 @@ Generating a Package Configuration File
 ``configure_package_config_file()`` should be used instead of the plain
 :command:`configure_file()` command when creating the ``<PackageName>Config.cmake``
 or ``<PackageName>-config.cmake`` file for installing a project or library.
-It helps making the resulting package relocatable by avoiding hardcoded paths
-in the installed ``Config.cmake`` file.
+It helps make the resulting package relocatable by avoiding hardcoded paths
+in the installed ``<PackageName>Config.cmake`` file.
 
 In a ``FooConfig.cmake`` file there may be code like this to make the install
-destinations know to the using project:
+destinations known to the using project:
 
 .. code-block:: cmake
 
@@ -40,27 +40,25 @@ destinations know to the using project:
    #...logic to determine installedPrefix from the own location...
    set(FOO_CONFIG_DIR  "${installedPrefix}/@CONFIG_INSTALL_DIR@" )
 
-All 4 options shown above are not sufficient, since the first 3 hardcode the
-absolute directory locations, and the 4th case works only if the logic to
+All four options shown above are not sufficient  The first three hardcode the
+absolute directory locations.  The fourth case works only if the logic to
 determine the ``installedPrefix`` is correct, and if ``CONFIG_INSTALL_DIR``
 contains a relative path, which in general cannot be guaranteed.  This has the
 effect that the resulting ``FooConfig.cmake`` file would work poorly under
-Windows and OSX, where users are used to choose the install location of a
+Windows and macOS, where users are used to choosing the install location of a
 binary package at install time, independent from how
 :variable:`CMAKE_INSTALL_PREFIX` was set at build/cmake time.
 
-Using ``configure_package_config_file`` helps.  If used correctly, it makes
+Using ``configure_package_config_file()`` helps.  If used correctly, it makes
 the resulting ``FooConfig.cmake`` file relocatable.  Usage:
 
-1. write a ``FooConfig.cmake.in`` file as you are used to
-2. insert a line containing only the string ``@PACKAGE_INIT@``
-3. instead of ``set(FOO_DIR "@SOME_INSTALL_DIR@")``, use
+1. Write a ``FooConfig.cmake.in`` file as you are used to.
+2. Insert a line at the top containing only the string ``@PACKAGE_INIT@``.
+3. Instead of ``set(FOO_DIR "@SOME_INSTALL_DIR@")``, use
    ``set(FOO_DIR "@PACKAGE_SOME_INSTALL_DIR@")`` (this must be after the
-   ``@PACKAGE_INIT@`` line)
-4. instead of using the normal :command:`configure_file()`, use
-   ``configure_package_config_file()``
-
-
+   ``@PACKAGE_INIT@`` line).
+4. Instead of using the normal :command:`configure_file()` command, use
+   ``configure_package_config_file()``.
 
 The ``<input>`` and ``<output>`` arguments are the input and output file, the
 same way as in :command:`configure_file()`.
@@ -70,48 +68,64 @@ the ``FooConfig.cmake`` file will be installed to.  This path can either be
 absolute, or relative to the ``INSTALL_PREFIX`` path.
 
 The variables ``<var1>`` to ``<varN>`` given as ``PATH_VARS`` are the
-variables which contain install destinations.  For each of them the macro will
+variables which contain install destinations.  For each of them, the macro will
 create a helper variable ``PACKAGE_<var...>``.  These helper variables must be
 used in the ``FooConfig.cmake.in`` file for setting the installed location.
-They are calculated by ``configure_package_config_file`` so that they are
+They are calculated by ``configure_package_config_file()`` so that they are
 always relative to the installed location of the package.  This works both for
-relative and also for absolute locations.  For absolute locations it works
+relative and also for absolute locations.  For absolute locations, it works
 only if the absolute location is a subdirectory of ``INSTALL_PREFIX``.
 
+.. versionadded:: 3.30
+  The variable ``PACKAGE_PREFIX_DIR`` will always be defined after the
+  ``@PACKAGE_INIT@`` line.  It will hold the value of the base install
+  location.  In general, variables defined via the ``PATH_VARS`` mechanism
+  should be used instead, but ``PACKAGE_PREFIX_DIR`` can be used for those
+  cases not easily handled by ``PATH_VARS``, such as for files installed
+  directly to the base install location rather than a subdirectory of it.
+
+  .. note::
+    When consumers of the generated file use CMake 3.29 or older, the value
+    of ``PACKAGE_PREFIX_DIR`` can be changed by a call to
+    :command:`find_dependency` or :command:`find_package`.
+    If a project relies on ``PACKAGE_PREFIX_DIR``, it is the project's
+    responsibility to ensure that the value of ``PACKAGE_PREFIX_DIR`` is
+    preserved across any such calls, or any other calls which might include
+    another file generated by ``configure_package_config_file()``.
+
 .. versionadded:: 3.1
-  If the ``INSTALL_PREFIX`` argument is passed, this is used as base path to
+  If the ``INSTALL_PREFIX`` argument is passed, this is used as the base path to
   calculate all the relative paths.  The ``<path>`` argument must be an absolute
   path.  If this argument is not passed, the :variable:`CMAKE_INSTALL_PREFIX`
   variable will be used instead.  The default value is good when generating a
-  FooConfig.cmake file to use your package from the install tree.  When
-  generating a FooConfig.cmake file to use your package from the build tree this
-  option should be used.
+  ``FooConfig.cmake`` file to use your package from the install tree.  When
+  generating a ``FooConfig.cmake`` file to use your package from the build tree,
+  this option should be used.
 
-By default ``configure_package_config_file`` also generates two helper macros,
-``set_and_check()`` and ``check_required_components()`` into the
+By default, ``configure_package_config_file()`` also generates two helper
+macros, ``set_and_check()`` and ``check_required_components()``, into the
 ``FooConfig.cmake`` file.
 
-``set_and_check()`` should be used instead of the normal ``set()`` command for
-setting directories and file locations.  Additionally to setting the variable
-it also checks that the referenced file or directory actually exists and fails
-with a ``FATAL_ERROR`` otherwise.  This makes sure that the created
+``set_and_check()`` should be used instead of the normal :command:`set` command
+for setting directories and file locations.  In addition to setting the
+variable, it also checks that the referenced file or directory actually exists
+and fails with a fatal error if it doesn't.  This ensures that the generated
 ``FooConfig.cmake`` file does not contain wrong references.
-When using the ``NO_SET_AND_CHECK_MACRO``, this macro is not generated
-into the ``FooConfig.cmake`` file.
+Add the ``NO_SET_AND_CHECK_MACRO`` option to prevent the generation of the
+``set_and_check()`` macro in the ``FooConfig.cmake`` file.
 
 ``check_required_components(<PackageName>)`` should be called at the end of
 the ``FooConfig.cmake`` file. This macro checks whether all requested,
-non-optional components have been found, and if this is not the case, sets
-the ``Foo_FOUND`` variable to ``FALSE``, so that the package is considered to
+non-optional components have been found, and if this is not the case, it sets
+the ``Foo_FOUND`` variable to ``FALSE`` so that the package is considered to
 be not found.  It does that by testing the ``Foo_<Component>_FOUND``
 variables for all requested required components.  This macro should be
 called even if the package doesn't provide any components to make sure
-users are not specifying components erroneously.  When using the
-``NO_CHECK_REQUIRED_COMPONENTS_MACRO`` option, this macro is not generated
-into the ``FooConfig.cmake`` file.
+users are not specifying components erroneously.  Add the
+``NO_CHECK_REQUIRED_COMPONENTS_MACRO`` option to prevent the generation of the
+``check_required_components()`` macro in the ``FooConfig.cmake`` file.
 
-For an example see below the documentation for
-:command:`write_basic_package_version_file()`.
+See also :ref:`CMakePackageConfigHelpers Examples`.
 
 Generating a Package Version File
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -126,11 +140,11 @@ Generating a Package Version File
      [ARCH_INDEPENDENT] )
 
 
-Writes a file for use as ``<PackageName>ConfigVersion.cmake`` file to
+Writes a file for use as a ``<PackageName>ConfigVersion.cmake`` file to
 ``<filename>``.  See the documentation of :command:`find_package()` for
-details on this.
+details on such files.
 
-``<filename>`` is the output filename, it should be in the build tree.
+``<filename>`` is the output filename, which should be in the build tree.
 ``<major.minor.patch>`` is the version number of the project to be installed.
 
 If no ``VERSION`` is given, the :variable:`PROJECT_VERSION` variable is used.
@@ -153,9 +167,9 @@ the requested version matches exactly its own version number (not considering
 the tweak version).  For example, version 1.2.3 of a package is only
 considered compatible to requested version 1.2.3.  This mode is for packages
 without compatibility guarantees.
-If your project has more elaborated version matching rules, you will need to
-write your own custom ``ConfigVersion.cmake`` file instead of using this
-macro.
+If your project has more elaborate version matching rules, you will need to
+write your own custom ``<PackageName>ConfigVersion.cmake`` file instead of
+using this macro.
 
 .. versionadded:: 3.11
   The ``SameMinorVersion`` compatibility mode.
@@ -170,13 +184,13 @@ macro.
   unless ``ARCH_INDEPENDENT`` is given, in which case the package is considered
   compatible on any architecture.
 
-.. note:: ``ARCH_INDEPENDENT`` is intended for header-only libraries or similar
-  packages with no binaries.
+  .. note:: ``ARCH_INDEPENDENT`` is intended for header-only libraries or
+    similar packages with no binaries.
 
 .. versionadded:: 3.19
   The version file generated by ``AnyNewerVersion``, ``SameMajorVersion`` and
-  ``SameMinorVersion`` arguments of ``COMPATIBILITY`` handle the version range
-  if any is specified (see :command:`find_package` command for the details).
+  ``SameMinorVersion`` arguments of ``COMPATIBILITY`` handle the version range,
+  if one is specified (see :command:`find_package` command for the details).
   ``ExactVersion`` mode is incompatible with version ranges and will display an
   author warning if one is specified.
 
@@ -184,8 +198,9 @@ Internally, this macro executes :command:`configure_file()` to create the
 resulting version file.  Depending on the ``COMPATIBILITY``, the corresponding
 ``BasicConfigVersion-<COMPATIBILITY>.cmake.in`` file is used.
 Please note that these files are internal to CMake and you should not call
-:command:`configure_file()` on them yourself, but they can be used as starting
-point to create more sophisticated custom ``ConfigVersion.cmake`` files.
+:command:`configure_file()` on them yourself, but they can be used as a starting
+point to create more sophisticated custom ``<PackageName>ConfigVersion.cmake``
+files.
 
 Generating an Apple Platform Selection File
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -268,6 +283,9 @@ Generating an Apple Platform Selection File
   consider the platform to be unsupported.  The behavior is determined
   by the ``ERROR_VARIABLE`` option.
 
+Generating an Apple Architecture Selection File
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 .. command:: generate_apple_architecture_selection_file
 
   .. versionadded:: 3.29
@@ -328,15 +346,16 @@ Generating an Apple Platform Selection File
     information to pretend the package was not found.  If this option
     is not given, the default behavior is to issue a fatal error.
 
+.. _`CMakePackageConfigHelpers Examples`:
+
 Example Generating Package Files
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Example using both :command:`configure_package_config_file` and
-``write_basic_package_version_file()``:
-
-``CMakeLists.txt``:
+Example using both the :command:`configure_package_config_file` and
+:command:`write_basic_package_version_file()` commands:
 
 .. code-block:: cmake
+   :caption: ``CMakeLists.txt``
 
    include(GNUInstallDirs)
    set(INCLUDE_INSTALL_DIR ${CMAKE_INSTALL_INCLUDEDIR}/Foo
@@ -357,9 +376,9 @@ Example using both :command:`configure_package_config_file` and
                  ${CMAKE_CURRENT_BINARY_DIR}/FooConfigVersion.cmake
            DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Foo )
 
-``FooConfig.cmake.in``:
-
-::
+.. code-block:: cmake
+   :caption: ``FooConfig.cmake.in``
+   :force:
 
    set(FOO_VERSION x.y.z)
    ...
@@ -597,8 +616,15 @@ function(generate_apple_architecture_selection_file _output_file)
       )
   endif()
   string(APPEND _branch_code
-    "endif()\n"
+    "endif()\n\n"
+    "set(_cmake_apple_archs \"\${CMAKE_OSX_ARCHITECTURES}\")\n"
     )
+  if(NOT "${_gasf_UNIVERSAL_ARCHITECTURES}" STREQUAL "")
+    string(APPEND _branch_code "list(REMOVE_ITEM _cmake_apple_archs ${_gasf_UNIVERSAL_ARCHITECTURES})\n")
+  endif()
+  string(APPEND _branch_code "\n")
+
+  set(maybe_else "")
 
   foreach(pair IN ZIP_LISTS _gasf_SINGLE_ARCHITECTURES _gasf_SINGLE_ARCHITECTURE_INCLUDE_FILES)
     set(arch "${pair_0}")
@@ -607,40 +633,45 @@ function(generate_apple_architecture_selection_file _output_file)
       string(PREPEND config_file [[${PACKAGE_PREFIX_DIR}/]])
     endif()
     string(APPEND _branch_code
-      "\n"
-      "if(CMAKE_OSX_ARCHITECTURES STREQUAL \"${arch}\")\n"
+      "${maybe_else}if(CMAKE_OSX_ARCHITECTURES STREQUAL \"${arch}\")\n"
       "  include(\"${config_file}\")\n"
-      "  return()\n"
-      "endif()\n"
       )
+    set(maybe_else else)
   endforeach()
 
   if(_gasf_UNIVERSAL_ARCHITECTURES AND _gasf_UNIVERSAL_INCLUDE_FILE)
-    string(JOIN " " universal_archs "${_gasf_UNIVERSAL_ARCHITECTURES}")
     set(config_file "${_gasf_UNIVERSAL_INCLUDE_FILE}")
     if(NOT IS_ABSOLUTE "${config_file}")
       string(PREPEND config_file [[${PACKAGE_PREFIX_DIR}/]])
     endif()
     string(APPEND _branch_code
-      "\n"
-      "set(_cmake_apple_archs \"\${CMAKE_OSX_ARCHITECTURES}\")\n"
-      "list(REMOVE_ITEM _cmake_apple_archs ${universal_archs})\n"
-      "if(NOT _cmake_apple_archs)\n"
+      "${maybe_else}if(NOT _cmake_apple_archs)\n"
       "  include(\"${config_file}\")\n"
-      "  return()\n"
-      "endif()\n"
       )
+    set(maybe_else else)
   elseif(_gasf_UNIVERSAL_ARCHITECTURES)
     message(FATAL_ERROR "UNIVERSAL_INCLUDE_FILE requires UNIVERSAL_ARCHITECTURES")
   elseif(_gasf_UNIVERSAL_INCLUDE_FILE)
     message(FATAL_ERROR "UNIVERSAL_ARCHITECTURES requires UNIVERSAL_INCLUDE_FILE")
   endif()
 
-  string(APPEND _branch_code "\n")
+  if(maybe_else)
+    string(APPEND _branch_code "else()\n")
+    set(_indent "  ")
+  else()
+    set(_indent "")
+  endif()
   if(_gasf_ERROR_VARIABLE)
-    string(APPEND _branch_code "set(\"${_gasf_ERROR_VARIABLE}\" \"Architecture not supported\")")
+    string(APPEND _branch_code
+      "${_indent}set(\"${_gasf_ERROR_VARIABLE}\" \"Architecture not supported\")\n"
+      )
   else()
-    string(APPEND _branch_code "message(FATAL_ERROR \"Architecture not supported\")")
+    string(APPEND _branch_code
+      "${_indent}message(FATAL_ERROR \"Architecture not supported\")\n"
+      )
+  endif()
+  if(maybe_else)
+    string(APPEND _branch_code "endif()\n")
   endif()
 
   configure_package_config_file("${CMAKE_CURRENT_FUNCTION_LIST_DIR}/Internal/AppleArchitectureSelection.cmake.in" "${_output_file}"

Modules/Internal/AppleArchitectureSelection.cmake.in

@@ -1,2 +1,23 @@
+# Save this now so we can restore it before returning
+if(NOT DEFINED PACKAGE_PREFIX_DIR)
+  list(APPEND _gasf_PACKAGE_PREFIX_DIR "<__CMAKE_UNDEFINED__>")
+elseif("${PACKAGE_PREFIX_DIR}" STREQUAL "")
+  list(APPEND _gasf_PACKAGE_PREFIX_DIR "<__CMAKE_EMPTY__>")
+else()
+  list(APPEND _gasf_PACKAGE_PREFIX_DIR "${PACKAGE_PREFIX_DIR}")
+endif()
+
 @PACKAGE_INIT@
 @_branch_code@
+
+# Restore PACKAGE_PREFIX_DIR
+list(LENGTH _gasf_PACKAGE_PREFIX_DIR _gasf_tmp)
+math(EXPR _gasf_tmp "${_gasf_tmp} - 1")
+list(GET _gasf_PACKAGE_PREFIX_DIR ${_gasf_tmp} PACKAGE_PREFIX_DIR)
+list(REMOVE_AT _gasf_PACKAGE_PREFIX_DIR ${_gasf_tmp})
+unset(_gasf_tmp)
+if("${PACKAGE_PREFIX_DIR}" STREQUAL "<__CMAKE_UNDEFINED__>")
+  unset(PACKAGE_PREFIX_DIR)
+elseif("${PACKAGE_PREFIX_DIR}" STREQUAL "<__CMAKE_EMPTY__>")
+  set(PACKAGE_PREFIX_DIR "")
+endif()

Modules/Internal/ApplePlatformSelection.cmake.in

@@ -1,3 +1,12 @@
+# Save this now so we can restore it before returning
+if(NOT DEFINED PACKAGE_PREFIX_DIR)
+  list(APPEND _gpsf_PACKAGE_PREFIX_DIR "<__CMAKE_UNDEFINED__>")
+elseif("${PACKAGE_PREFIX_DIR}" STREQUAL "")
+  list(APPEND _gpsf_PACKAGE_PREFIX_DIR "<__CMAKE_EMPTY__>")
+else()
+  list(APPEND _gpsf_PACKAGE_PREFIX_DIR "${PACKAGE_PREFIX_DIR}")
+endif()
+
 @PACKAGE_INIT@
 
 string(TOLOWER "${CMAKE_OSX_SYSROOT}" _CMAKE_OSX_SYSROOT_LOWER)
@@ -23,3 +32,15 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
 else()
   @_branch_ELSE@
 endif()
+
+# Restore PACKAGE_PREFIX_DIR
+list(LENGTH _gpsf_PACKAGE_PREFIX_DIR _gpsf_tmp)
+math(EXPR _gpsf_tmp "${_gpsf_tmp} - 1")
+list(GET _gpsf_PACKAGE_PREFIX_DIR ${_gpsf_tmp} PACKAGE_PREFIX_DIR)
+list(REMOVE_AT _gpsf_PACKAGE_PREFIX_DIR ${_gpsf_tmp})
+unset(_gpsf_tmp)
+if("${PACKAGE_PREFIX_DIR}" STREQUAL "<__CMAKE_UNDEFINED__>")
+  unset(PACKAGE_PREFIX_DIR)
+elseif("${PACKAGE_PREFIX_DIR}" STREQUAL "<__CMAKE_EMPTY__>")
+  set(PACKAGE_PREFIX_DIR "")
+endif()

Source/cmFindPackageCommand.cxx

@@ -982,6 +982,36 @@ bool cmFindPackageCommand::InitialPass(std::vector<std::string> const& args)
     return true;
   }
 
+  // Restore PACKAGE_PREFIX_DIR to its pre-call value when we return. If our
+  // caller is a file generated by configure_package_config_file(), and if
+  // the package we are about to load also has a config file created by that
+  // command, it will overwrite PACKAGE_PREFIX_DIR. We need to restore it in
+  // case something still refers to it in our caller's scope after we return.
+  class RestoreVariableOnLeavingScope
+  {
+    cmMakefile* makefile_;
+    cm::optional<std::string> value_;
+
+  public:
+    RestoreVariableOnLeavingScope(cmMakefile* makefile)
+      : makefile_(makefile)
+    {
+      cmValue v = makefile->GetDefinition("PACKAGE_PREFIX_DIR");
+      if (v) {
+        value_ = *v;
+      }
+    }
+    ~RestoreVariableOnLeavingScope()
+    {
+      if (this->value_) {
+        makefile_->AddDefinition("PACKAGE_PREFIX_DIR", *value_);
+      } else {
+        makefile_->RemoveDefinition("PACKAGE_PREFIX_DIR");
+      }
+    }
+  };
+  RestoreVariableOnLeavingScope restorePackagePrefixDir(this->Makefile);
+
   // Now choose what method(s) we will use to satisfy the request. Note that
   // we still want all the above checking of arguments, etc. regardless of the
   // method used. This will ensure ill-formed arguments are caught earlier,

Tests/RunCMake/CMakePackage/ApplePlatformGenSubdir-stdout.txt

@@ -0,0 +1,3 @@
+(-- )?Hello from platform switch
+(-- )?Hello from arch switch
+(-- )?Hello from pkg_a

Tests/RunCMake/CMakePackage/ApplePlatformGenSubdir.cmake

@@ -0,0 +1,50 @@
+set(CMAKE_INSTALL_DATADIR share)
+set(SWITCH_DIR platform/cmake)
+
+include(CMakePackageConfigHelpers)
+
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/pkg_a-config.cmake.in [[
+@PACKAGE_INIT@
+include("@PACKAGE_SWITCH_DIR@/platform-switch.cmake")
+include("@PACKAGE_CMAKE_INSTALL_DATADIR@/pkg_a_included.cmake")
+]])
+configure_package_config_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/pkg_a-config.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/install/pkg_a-config.cmake
+  INSTALL_DESTINATION .
+  PATH_VARS CMAKE_INSTALL_DATADIR SWITCH_DIR
+)
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/install/${CMAKE_INSTALL_DATADIR}/pkg_a_included.cmake
+  [[message(STATUS "Hello from pkg_a")]]
+)
+
+# To expose re-using the same package prefix variable, we need to use a
+# different install prefix. This is really contrived and not representative of
+# what a package should do.
+generate_apple_platform_selection_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/install/platform/cmake/platform-switch.cmake
+  INSTALL_PREFIX ${CMAKE_INSTALL_PREFIX}/platform
+  INSTALL_DESTINATION cmake
+  MACOS_INCLUDE_FILE cmake/switch_included.cmake  # relative to install prefix
+)
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/install/platform/cmake/switch_included.cmake
+[[
+message(STATUS "Hello from platform switch")
+include("${CMAKE_CURRENT_LIST_DIR}/../arch/cmake/arch-switch.cmake")
+]]
+)
+
+generate_apple_architecture_selection_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/install/platform/arch/cmake/arch-switch.cmake
+  INSTALL_PREFIX ${CMAKE_INSTALL_PREFIX}/platform/arch
+  INSTALL_DESTINATION cmake
+  UNIVERSAL_ARCHITECTURES i386 x86_64 arm64 $(ARCHS_STANDARD)
+  UNIVERSAL_INCLUDE_FILE cmake/switch_included.cmake  # relative to install prefix
+)
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/install/platform/arch/cmake/switch_included.cmake
+  [[message(STATUS "Hello from arch switch")]]
+)
+
+find_package(pkg_a REQUIRED NO_DEFAULT_PATH
+  PATHS ${CMAKE_CURRENT_BINARY_DIR}/install
+)

Tests/RunCMake/CMakePackage/NestedConfigFile-stdout.txt

@@ -0,0 +1,6 @@
+(-- )?Before find_dependency: PACKAGE_PREFIX_DIR = .*/Tests/RunCMake/CMakePackage/NestedConfigFile-build/install_pkg_b
+(-- )?Hello from pkg_a
+(-- )?Leaving pkg_a-config\.cmake with PACKAGE_PREFIX_DIR = .*/Tests/RunCMake/CMakePackage/NestedConfigFile-build/install_pkg_a
+(-- )?After find_dependency:  PACKAGE_PREFIX_DIR = .*/Tests/RunCMake/CMakePackage/NestedConfigFile-build/install_pkg_b
+(-- )?Hello from pkg_b
+(-- )?Leaving pkg_b-config\.cmake with PACKAGE_PREFIX_DIR = .*/Tests/RunCMake/CMakePackage/NestedConfigFile-build/install_pkg_b

Tests/RunCMake/CMakePackage/NestedConfigFile.cmake

@@ -0,0 +1,43 @@
+set(CMAKE_INSTALL_DATADIR share)
+
+include(CMakePackageConfigHelpers)
+
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/pkg_a-config.cmake.in [[
+@PACKAGE_INIT@
+include("@PACKAGE_CMAKE_INSTALL_DATADIR@/pkg_a_included.cmake")
+message(STATUS "Leaving pkg_a-config.cmake with PACKAGE_PREFIX_DIR = ${PACKAGE_PREFIX_DIR}")
+]])
+configure_package_config_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/pkg_a-config.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/install_pkg_a/pkg_a-config.cmake
+  INSTALL_DESTINATION .
+  PATH_VARS CMAKE_INSTALL_DATADIR
+)
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/install_pkg_a/share/pkg_a_included.cmake
+  [[message(STATUS "Hello from pkg_a")]]
+)
+
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/pkg_b-config.cmake.in [[
+@PACKAGE_INIT@
+include(CMakeFindDependencyMacro)
+message(STATUS "Before find_dependency: PACKAGE_PREFIX_DIR = ${PACKAGE_PREFIX_DIR}")
+find_dependency(pkg_a NO_DEFAULT_PATH
+    PATHS "@CMAKE_CURRENT_BINARY_DIR@/install_pkg_a"
+)
+message(STATUS "After find_dependency:  PACKAGE_PREFIX_DIR = ${PACKAGE_PREFIX_DIR}")
+include("@PACKAGE_CMAKE_INSTALL_DATADIR@/pkg_b_included.cmake")
+message(STATUS "Leaving pkg_b-config.cmake with PACKAGE_PREFIX_DIR = ${PACKAGE_PREFIX_DIR}")
+]])
+configure_package_config_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/pkg_b-config.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/install_pkg_b/pkg_b-config.cmake
+  INSTALL_DESTINATION .
+  PATH_VARS CMAKE_INSTALL_DATADIR
+)
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/install_pkg_b/share/pkg_b_included.cmake
+  [[message(STATUS "Hello from pkg_b")]]
+)
+
+find_package(pkg_b REQUIRED NO_DEFAULT_PATH
+  PATHS ${CMAKE_CURRENT_BINARY_DIR}/install_pkg_b
+)

Tests/RunCMake/CMakePackage/RunCMakeTest.cmake

@@ -4,6 +4,8 @@ if(NOT RunCMake_GENERATOR_IS_MULTI_CONFIG)
   set(maybe_CMAKE_BUILD_TYPE -DCMAKE_BUILD_TYPE=Release)
 endif()
 
+run_cmake_with_options(NestedConfigFile ${maybe_CMAKE_BUILD_TYPE})
+
 function(apple_export platform system_name archs sysroot)
   set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/apple-export-${platform}-build)
   string(REPLACE ";" "\\;" archs "${archs}")
@@ -48,9 +50,6 @@ if(APPLE)
 endif()
 
 if(APPLE AND CMAKE_C_COMPILER_ID STREQUAL "AppleClang")
-  set(apple_install ${RunCMake_BINARY_DIR}/apple-install)
-  file(REMOVE_RECURSE "${apple_install}")
-
   if(CMake_TEST_XCODE_VERSION VERSION_GREATER_EQUAL 12)
     set(macos_archs "x86_64;arm64")
     set(tvos_sim_archs "x86_64;arm64")
@@ -78,6 +77,17 @@ if(APPLE AND CMAKE_C_COMPILER_ID STREQUAL "AppleClang")
     set(enable_visionos 1)
   endif()
 
+  string(REPLACE ";" "\\;" macos_archs_for_cmd "${macos_archs}")
+  run_cmake_with_options(ApplePlatformGenSubdir
+    "-DCMAKE_OSX_ARCHITECTURES=${macos_archs_for_cmd}"
+    ${maybe_CMAKE_BUILD_TYPE}
+  )
+  unset(macos_archs_for_cmd)
+
+  # Place all export/import steps in a single install prefix.
+  set(apple_install ${RunCMake_BINARY_DIR}/apple-install)
+  file(REMOVE_RECURSE "${apple_install}")
+
   apple_export(macos Darwin "${macos_archs}" macosx)
   apple_export(ios iOS "arm64" iphoneos)
   apple_export(tvos tvOS "arm64" appletvos)