Merge topic 'fetchcontent-reject-CMAKE_TOOLCHAIN_FILE-env-var'

c15674a9cb FetchContent: Reject CMAKE_TOOLCHAIN_FILE env var in sub-build
31ef93f19f FetchContent: Only use @-@ replacements for sub-build CMakeLists.txt

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !8248

Modules/FetchContent.cmake

@@ -1598,7 +1598,9 @@ set_property(GLOBAL PROPERTY _CMAKE_FindGit_GIT_EXECUTABLE_VERSION
   # has this set to something not findable on the PATH. We also ensured above
   # that the Debug config will be defined for multi-config generators.
   configure_file("${CMAKE_CURRENT_FUNCTION_LIST_DIR}/FetchContent/CMakeLists.cmake.in"
-                 "${ARG_SUBBUILD_DIR}/CMakeLists.txt")
+                 "${ARG_SUBBUILD_DIR}/CMakeLists.txt"
+                 @ONLY
+  )
   execute_process(
     COMMAND ${CMAKE_COMMAND} ${subCMakeOpts} .
     RESULT_VARIABLE result

Modules/FetchContent/CMakeLists.cmake.in

@@ -1,21 +1,27 @@
 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
 # file Copyright.txt or https://cmake.org/licensing for details.
 
-cmake_minimum_required(VERSION ${CMAKE_VERSION})
+cmake_minimum_required(VERSION @CMAKE_VERSION@)
+
+# Reject any attempt to use a toolchain file. We must not use one because
+# we could be downloading it here. If the CMAKE_TOOLCHAIN_FILE environment
+# variable is set, the cache variable will have been initialized from it.
+unset(CMAKE_TOOLCHAIN_FILE CACHE)
+unset(ENV{CMAKE_TOOLCHAIN_FILE})
 
 # 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
 # something goes wrong and an error message is produced.
 
-project(${contentName}-populate NONE)
+project(@contentName@-populate NONE)
 
 @__FETCHCONTENT_CACHED_INFO@
 
 include(ExternalProject)
-ExternalProject_Add(${contentName}-populate
-                    ${ARG_EXTRA}
-                    SOURCE_DIR          "${ARG_SOURCE_DIR}"
-                    BINARY_DIR          "${ARG_BINARY_DIR}"
+ExternalProject_Add(@contentName@-populate
+                    @ARG_EXTRA@
+                    SOURCE_DIR          "@ARG_SOURCE_DIR@"
+                    BINARY_DIR          "@ARG_BINARY_DIR@"
                     CONFIGURE_COMMAND   ""
                     BUILD_COMMAND       ""
                     INSTALL_COMMAND     ""

Tests/RunCMake/FetchContent/IgnoreToolchainFile.cmake

@@ -0,0 +1,2 @@
+set(ENV{CMAKE_TOOLCHAIN_FILE} path/to/somewhere/iDoNotExist.cmake)
+include(DownloadFile.cmake)

Tests/RunCMake/FetchContent/RunCMakeTest.cmake

@@ -7,6 +7,7 @@ run_cmake(DirectIgnoresDetails)
 run_cmake(FirstDetailsWin)
 run_cmake(DownloadTwice)
 run_cmake(DownloadFile)
+run_cmake(IgnoreToolchainFile)
 run_cmake(SameGenerator)
 run_cmake(System)
 run_cmake(VarDefinitions)