ExternalProject: Use CMP0114 NEW behavior with Xcode "new build system"

The ExternalProject module cannot be implemented in the Xcode "new build
system" without using CMP0114's NEW behavior.  When configuring for that
build system, warn if the policy is not set to NEW and use NEW behavior
anyway.

12 files changed, 74 insertions, 8 deletions

diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index b795784fc3..8bbaf5a38a 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -3342,6 +3342,18 @@ function(ExternalProject_Add name)
   cmake_policy(GET CMP0114 cmp0114
     PARENT_SCOPE # undocumented, do not use outside of CMake
     )
+  if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12 AND NOT cmp0114 STREQUAL "NEW")
+    message(AUTHOR_WARNING
+      "Policy CMP0114 is not set to NEW.  "
+      "In order to support the Xcode \"new build system\", "
+      "this project must be updated to set policy CMP0114 to NEW."
+      "\n"
+      "Since CMake is generating for the Xcode \"new build system\", "
+      "ExternalProject_Add will use policy CMP0114's NEW behavior anyway, "
+      "but the generated build system may not match what the project intends."
+      )
+    set(cmp0114 "NEW")
+  endif()
 
   _ep_get_configuration_subdir_suffix(cfgdir)
 
diff --git a/Modules/FetchContent/CMakeLists.cmake.in b/Modules/FetchContent/CMakeLists.cmake.in
index 45e4df03ef..951641820a 100644
--- a/Modules/FetchContent/CMakeLists.cmake.in
+++ b/Modules/FetchContent/CMakeLists.cmake.in
@@ -2,6 +2,7 @@
 # file Copyright.txt or https://cmake.org/licensing for details.
 
 cmake_minimum_required(VERSION ${CMAKE_VERSION})
+cmake_policy(SET CMP0114 NEW)
 
 # We name the project and the target for the ExternalProject_Add() call
 # to something that will highlight to the user what we are working on if
diff --git a/Tests/ExternalProject/CMakeLists.txt b/Tests/ExternalProject/CMakeLists.txt
index c8850eaf2d..29cdcc99ea 100644
--- a/Tests/ExternalProject/CMakeLists.txt
+++ b/Tests/ExternalProject/CMakeLists.txt
@@ -1,5 +1,8 @@
 cmake_minimum_required(VERSION 2.8)
 project(ExternalProjectTest NONE)
+if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12)
+  cmake_policy(SET CMP0114 NEW)
+endif()
 
 include(ExternalProject)
 
diff --git a/Tests/ExternalProjectLocal/CMakeLists.txt b/Tests/ExternalProjectLocal/CMakeLists.txt
index 1075a9d079..789e4fb290 100644
--- a/Tests/ExternalProjectLocal/CMakeLists.txt
+++ b/Tests/ExternalProjectLocal/CMakeLists.txt
@@ -1,5 +1,8 @@
 cmake_minimum_required(VERSION 2.8)
 project(ExternalProjectLocalTest NONE)
+if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12)
+  cmake_policy(SET CMP0114 NEW)
+endif()
 
 include(ExternalProject)
 
diff --git a/Tests/ExternalProjectUpdate/CMakeLists.txt b/Tests/ExternalProjectUpdate/CMakeLists.txt
index 9dddae2078..563a6cf9f3 100644
--- a/Tests/ExternalProjectUpdate/CMakeLists.txt
+++ b/Tests/ExternalProjectUpdate/CMakeLists.txt
@@ -1,5 +1,9 @@
 cmake_minimum_required(VERSION 2.8)
 project(ExternalProjectUpdateTest NONE)
+if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12)
+  cmake_policy(SET CMP0114 NEW)
+endif()
+cmake_policy(GET CMP0114 cmp0114)
 
 include(ExternalProject)
 
@@ -18,8 +22,16 @@ set_property(GLOBAL PROPERTY PREDEFINED_TARGETS_FOLDER
 set(base "${CMAKE_BINARY_DIR}/CMakeExternals")
 set(binary_base "${base}/Build")
 set_property(DIRECTORY PROPERTY EP_BASE ${base})
-set_property(DIRECTORY PROPERTY EP_STEP_TARGETS configure build test)
-set_property(DIRECTORY PROPERTY EP_INDEPENDENT_STEP_TARGETS update)
+if(cmp0114 STREQUAL "NEW")
+  set_property(DIRECTORY PROPERTY EP_STEP_TARGETS configure build test update)
+  set(TestUpdateCommand_STEP_TARGETS STEP_TARGETS update)
+  set(TestUpdateCommand_INDEPENDENT_STEP_TARGETS)
+else()
+  set_property(DIRECTORY PROPERTY EP_STEP_TARGETS configure build test)
+  set_property(DIRECTORY PROPERTY EP_INDEPENDENT_STEP_TARGETS update)
+  set(TestUpdateCommand_STEP_TARGETS)
+  set(TestUpdateCommand_INDEPENDENT_STEP_TARGETS INDEPENDENT_STEP_TARGETS update)
+endif()
 
 ExternalProject_Add(TestUpdateCommand
   SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}
@@ -28,7 +40,8 @@ ExternalProject_Add(TestUpdateCommand
   CONFIGURE_COMMAND ""
   BUILD_COMMAND ""
   INSTALL_COMMAND ""
-  INDEPENDENT_STEP_TARGETS update
+  ${TestUpdateCommand_STEP_TARGETS}
+  ${TestUpdateCommand_INDEPENDENT_STEP_TARGETS}
   )
 add_custom_target(TestUpdateCommandDriver ALL)
 add_dependencies(TestUpdateCommandDriver TestUpdateCommand-update)
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 39455b7bd8..ff0ae62a7e 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -569,6 +569,9 @@ add_RunCMake_test(file-GET_RUNTIME_DEPENDENCIES
 add_RunCMake_test(CPackCommandLine)
 add_RunCMake_test(CPackConfig)
 add_RunCMake_test(CPackInstallProperties)
+if(XCODE_VERSION)
+  set(ExternalProject_ARGS -DXCODE_VERSION=${XCODE_VERSION})
+endif()
 add_RunCMake_test(ExternalProject)
 add_RunCMake_test(FetchContent)
 set(CTestCommandLine_ARGS -DPYTHON_EXECUTABLE=${PYTHON_EXECUTABLE})
diff --git a/Tests/RunCMake/ExternalProject/Add_StepDependencies.cmake b/Tests/RunCMake/ExternalProject/Add_StepDependencies.cmake
index 4e43ab3921..bfed4fa7cc 100644
--- a/Tests/RunCMake/ExternalProject/Add_StepDependencies.cmake
+++ b/Tests/RunCMake/ExternalProject/Add_StepDependencies.cmake
@@ -1,5 +1,9 @@
 cmake_minimum_required(VERSION ${CMAKE_VERSION})
-cmake_policy(SET CMP0114 OLD) # Test deprecated behavior.
+if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12)
+  cmake_policy(SET CMP0114 NEW)
+else()
+  cmake_policy(SET CMP0114 OLD) # Test deprecated behavior.
+endif()
 
 include(ExternalProject)
 
diff --git a/Tests/RunCMake/ExternalProject/Add_StepDependencies_no_target.cmake b/Tests/RunCMake/ExternalProject/Add_StepDependencies_no_target.cmake
index 7c750076d4..039dec6a1c 100644
--- a/Tests/RunCMake/ExternalProject/Add_StepDependencies_no_target.cmake
+++ b/Tests/RunCMake/ExternalProject/Add_StepDependencies_no_target.cmake
@@ -1,5 +1,9 @@
 cmake_minimum_required(VERSION ${CMAKE_VERSION})
-cmake_policy(SET CMP0114 OLD) # Test deprecated behavior.
+if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12)
+  cmake_policy(SET CMP0114 NEW)
+else()
+  cmake_policy(SET CMP0114 OLD) # Test deprecated behavior.
+endif()
 
 include(ExternalProject)
 
diff --git a/Tests/RunCMake/ExternalProject/CMakeLists.txt b/Tests/RunCMake/ExternalProject/CMakeLists.txt
index c585733b67..9cb093a437 100644
--- a/Tests/RunCMake/ExternalProject/CMakeLists.txt
+++ b/Tests/RunCMake/ExternalProject/CMakeLists.txt
@@ -1,3 +1,6 @@
 cmake_minimum_required(VERSION ${CMAKE_VERSION})
 project(${RunCMake_TEST} NONE)
+if(CMAKE_XCODE_BUILD_SYSTEM VERSION_GREATER_EQUAL 12 AND NOT RunCMake_TEST STREQUAL "Xcode-CMP0114")
+  cmake_policy(SET CMP0114 NEW)
+endif()
 include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/ExternalProject/RunCMakeTest.cmake b/Tests/RunCMake/ExternalProject/RunCMakeTest.cmake
index 1e88e0ba9b..598671f820 100644
--- a/Tests/RunCMake/ExternalProject/RunCMakeTest.cmake
+++ b/Tests/RunCMake/ExternalProject/RunCMakeTest.cmake
@@ -16,8 +16,10 @@ run_cmake(SourceMissing)
 run_cmake(CMAKE_CACHE_ARGS)
 run_cmake(CMAKE_CACHE_DEFAULT_ARGS)
 run_cmake(CMAKE_CACHE_mix)
-run_cmake(NO_DEPENDS-CMP0114-WARN)
-run_cmake(NO_DEPENDS-CMP0114-OLD)
+if(NOT XCODE_VERSION OR XCODE_VERSION VERSION_LESS 12)
+  run_cmake(NO_DEPENDS-CMP0114-WARN)
+  run_cmake(NO_DEPENDS-CMP0114-OLD)
+endif()
 run_cmake(NO_DEPENDS-CMP0114-NEW)
 run_cmake(NO_DEPENDS-CMP0114-NEW-Direct)
 run_cmake(Add_StepDependencies)
@@ -25,6 +27,9 @@ run_cmake(Add_StepDependencies_iface)
 run_cmake(Add_StepDependencies_iface_step)
 run_cmake(Add_StepDependencies_no_target)
 run_cmake(UsesTerminal)
+if(XCODE_VERSION AND XCODE_VERSION VERSION_GREATER_EQUAL 12)
+  run_cmake(Xcode-CMP0114)
+endif()
 
 macro(check_steps_missing proj)
   set(steps "${ARGN}")
@@ -53,7 +58,9 @@ function(run_steps_CMP0114 val)
   run_cmake_command(Steps-CMP0114-${val}-build-install ${CMAKE_COMMAND} --build . --target proj1-install)
   run_cmake_command(Steps-CMP0114-${val}-build-test ${CMAKE_COMMAND} --build . --target proj1-test)
 endfunction()
-run_steps_CMP0114(OLD)
+if(NOT XCODE_VERSION OR XCODE_VERSION VERSION_LESS 12)
+  run_steps_CMP0114(OLD)
+endif()
 run_steps_CMP0114(NEW)
 
 # Run both cmake and build steps. We always do a clean before the
diff --git a/Tests/RunCMake/ExternalProject/Xcode-CMP0114-stderr.txt b/Tests/RunCMake/ExternalProject/Xcode-CMP0114-stderr.txt
new file mode 100644
index 0000000000..a616185c96
--- /dev/null
+++ b/Tests/RunCMake/ExternalProject/Xcode-CMP0114-stderr.txt
@@ -0,0 +1,11 @@
+^CMake Warning \(dev\) at .*/Modules/ExternalProject.cmake:[0-9]+ \(message\):
+  Policy CMP0114 is not set to NEW.  In order to support the Xcode "new build
+  system", this project must be updated to set policy CMP0114 to NEW.
+
+  Since CMake is generating for the Xcode "new build system",
+  ExternalProject_Add will use policy CMP0114's NEW behavior anyway, but the
+  generated build system may not match what the project intends.
+Call Stack \(most recent call first\):
+  Xcode-CMP0114.cmake:[0-9]+ \(ExternalProject_Add\)
+  CMakeLists.txt:[0-9]+ \(include\)
+This warning is for project developers.  Use -Wno-dev to suppress it.$
diff --git a/Tests/RunCMake/ExternalProject/Xcode-CMP0114.cmake b/Tests/RunCMake/ExternalProject/Xcode-CMP0114.cmake
new file mode 100644
index 0000000000..5039daacaf
--- /dev/null
+++ b/Tests/RunCMake/ExternalProject/Xcode-CMP0114.cmake
@@ -0,0 +1,2 @@
+include(ExternalProject)
+ExternalProject_Add(MyProj SOURCE_DIR .)