Xcode: Switch to the "new build system" for Xcode 12 and above

Provide an option to switch back to the original build system via
`-T buildsystem=1`.

Fixes: #18088

17 files changed, 68 insertions, 3 deletions

diff --git a/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem-stderr.txt b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem-stderr.txt
index 9ef6b20..5e88e3b 100644
--- a/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem-stderr.txt
+++ b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem-stderr.txt
@@ -7,4 +7,4 @@ CMake Error at CMakeLists.txt:[0-9]+ \(project\):
 
     buildsystem=bad
 
-  value is unkonwn.  It must be '1'\.$
+  value is unkonwn.  It must be '1' or '12'\.$
diff --git a/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12-result.txt b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12-stderr.txt b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12-stderr.txt
new file mode 100644
index 0000000..cdfae3e
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12-stderr.txt
@@ -0,0 +1,10 @@
+CMake Error at CMakeLists.txt:[0-9]+ \(project\):
+  Generator
+
+    Xcode
+
+  toolset specification field
+
+    buildsystem=12
+
+  is not allowed with Xcode [0-9.]+\.$
diff --git a/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12.cmake b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12.cmake
new file mode 100644
index 0000000..2fc38e5
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/BadToolsetXcodeBuildSystem12.cmake
@@ -0,0 +1 @@
+message(FATAL_ERROR "This should not be reached!")
diff --git a/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake b/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake
index af59019..5f12d79 100644
--- a/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake
+++ b/Tests/RunCMake/GeneratorToolset/RunCMakeTest.cmake
@@ -56,8 +56,19 @@ elseif("${RunCMake_GENERATOR}" STREQUAL "Xcode")
   run_cmake(BadToolsetHostArchXcode)
   set(RunCMake_GENERATOR_TOOLSET "buildsystem=bad")
   run_cmake(BadToolsetXcodeBuildSystem)
-  set(RunCMake_GENERATOR_TOOLSET "Test Toolset")
-  run_cmake(TestToolsetXcodeBuildSystemDefault1)
+  if(XCODE_VERSION VERSION_GREATER_EQUAL 12)
+    set(RunCMake_GENERATOR_TOOLSET "Test Toolset")
+    run_cmake(TestToolsetXcodeBuildSystemDefault12)
+    set(RunCMake_GENERATOR_TOOLSET "Test Toolset,buildsystem=1")
+    run_cmake(TestToolsetXcodeBuildSystem1)
+    set(RunCMake_GENERATOR_TOOLSET "Test Toolset,buildsystem=12")
+    run_cmake(TestToolsetXcodeBuildSystem12)
+  else()
+    set(RunCMake_GENERATOR_TOOLSET "Test Toolset")
+    run_cmake(TestToolsetXcodeBuildSystemDefault1)
+    set(RunCMake_GENERATOR_TOOLSET "buildsystem=12")
+    run_cmake(BadToolsetXcodeBuildSystem12)
+  endif()
 else()
   set(RunCMake_GENERATOR_TOOLSET "Bad Toolset")
   run_cmake(BadToolset)
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-result.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-stderr.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-stderr.txt
new file mode 100644
index 0000000..817467b
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at TestToolsetXcodeBuildSystem1.cmake:[0-9]+ \(message\):
+  CMAKE_GENERATOR_TOOLSET is "Test Toolset,buildsystem=1" as expected.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-stdout.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-stdout.txt
new file mode 100644
index 0000000..cba95ce
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1-stdout.txt
@@ -0,0 +1 @@
+CMAKE_XCODE_BUILD_SYSTEM='1'
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1.cmake b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1.cmake
new file mode 100644
index 0000000..550a6a1
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem1.cmake
@@ -0,0 +1,8 @@
+message(STATUS "CMAKE_XCODE_BUILD_SYSTEM='${CMAKE_XCODE_BUILD_SYSTEM}'")
+if(CMAKE_GENERATOR_TOOLSET STREQUAL "Test Toolset,buildsystem=1")
+  message(FATAL_ERROR "CMAKE_GENERATOR_TOOLSET is \"Test Toolset,buildsystem=1\" as expected.")
+else()
+  message(FATAL_ERROR
+    "CMAKE_GENERATOR_TOOLSET is \"${CMAKE_GENERATOR_TOOLSET}\" "
+    "but should be \"Test Toolset,buildsystem=1\"!")
+endif()
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-result.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-stderr.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-stderr.txt
new file mode 100644
index 0000000..9352faf
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at TestToolsetXcodeBuildSystem12.cmake:[0-9]+ \(message\):
+  CMAKE_GENERATOR_TOOLSET is "Test Toolset,buildsystem=12" as expected.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-stdout.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-stdout.txt
new file mode 100644
index 0000000..df49a31
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12-stdout.txt
@@ -0,0 +1 @@
+CMAKE_XCODE_BUILD_SYSTEM='12'
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12.cmake b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12.cmake
new file mode 100644
index 0000000..7e30e43
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystem12.cmake
@@ -0,0 +1,8 @@
+message(STATUS "CMAKE_XCODE_BUILD_SYSTEM='${CMAKE_XCODE_BUILD_SYSTEM}'")
+if(CMAKE_GENERATOR_TOOLSET STREQUAL "Test Toolset,buildsystem=12")
+  message(FATAL_ERROR "CMAKE_GENERATOR_TOOLSET is \"Test Toolset,buildsystem=12\" as expected.")
+else()
+  message(FATAL_ERROR
+    "CMAKE_GENERATOR_TOOLSET is \"${CMAKE_GENERATOR_TOOLSET}\" "
+    "but should be \"Test Toolset,buildsystem=12\"!")
+endif()
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-result.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-stderr.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-stderr.txt
new file mode 100644
index 0000000..1d43537
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at TestToolsetXcodeBuildSystemDefault12.cmake:[0-9]+ \(message\):
+  CMAKE_GENERATOR_TOOLSET is "Test Toolset" as expected.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-stdout.txt b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-stdout.txt
new file mode 100644
index 0000000..df49a31
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12-stdout.txt
@@ -0,0 +1 @@
+CMAKE_XCODE_BUILD_SYSTEM='12'
diff --git a/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12.cmake b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12.cmake
new file mode 100644
index 0000000..645bb19
--- /dev/null
+++ b/Tests/RunCMake/GeneratorToolset/TestToolsetXcodeBuildSystemDefault12.cmake
@@ -0,0 +1,8 @@
+message(STATUS "CMAKE_XCODE_BUILD_SYSTEM='${CMAKE_XCODE_BUILD_SYSTEM}'")
+if(CMAKE_GENERATOR_TOOLSET STREQUAL "Test Toolset")
+  message(FATAL_ERROR "CMAKE_GENERATOR_TOOLSET is \"Test Toolset\" as expected.")
+else()
+  message(FATAL_ERROR
+    "CMAKE_GENERATOR_TOOLSET is \"${CMAKE_GENERATOR_TOOLSET}\" "
+    "but should be \"Test Toolset\"!")
+endif()