load_cache: Allow READ_WITH_PREFIX mode in cmake scripts

Help/release/dev/load_cache-script-mode.rst

+load_cache-script-mode
+----------------------
+
+* The :command:`load_cache(READ_WITH_PREFIX)` command mode is now allowed
+  when using ``cmake -P`` to :ref:`Run a Script <Script Processing Mode>`.

Source/cmCommands.cxx

@@ -198,6 +198,7 @@ void GetScriptingCommands(cmState* state)
 #if !defined(CMAKE_BOOTSTRAP)
   state->AddBuiltinCommand("cmake_host_system_information",
                            cmCMakeHostSystemInformationCommand);
+  state->AddBuiltinCommand("load_cache", cmLoadCacheCommand);
   state->AddBuiltinCommand("remove", cmRemoveCommand);
   state->AddBuiltinCommand("variable_watch", cmVariableWatchCommand);
   state->AddBuiltinCommand("write_file", cmWriteFileCommand);
@@ -279,7 +280,6 @@ void GetProjectCommands(cmState* state)
   state->AddBuiltinCommand("target_link_options", cmTargetLinkOptionsCommand);
   state->AddBuiltinCommand("target_link_directories",
                            cmTargetLinkDirectoriesCommand);
-  state->AddBuiltinCommand("load_cache", cmLoadCacheCommand);
   state->AddBuiltinCommand("qt_wrap_cpp", cmQTWrapCPPCommand);
   state->AddBuiltinCommand("qt_wrap_ui", cmQTWrapUICommand);
   state->AddBuiltinCommand("remove_definitions", cmRemoveDefinitionsCommand);
@@ -339,7 +339,6 @@ void GetProjectCommandsInScriptMode(cmState* state)
   CM_UNEXPECTED_PROJECT_COMMAND("install");
   CM_UNEXPECTED_PROJECT_COMMAND("link_directories");
   CM_UNEXPECTED_PROJECT_COMMAND("link_libraries");
-  CM_UNEXPECTED_PROJECT_COMMAND("load_cache");
   CM_UNEXPECTED_PROJECT_COMMAND("project");
   CM_UNEXPECTED_PROJECT_COMMAND("qt_wrap_cpp");
   CM_UNEXPECTED_PROJECT_COMMAND("qt_wrap_ui");

Source/cmLoadCacheCommand.cxx

@@ -24,12 +24,20 @@ bool cmLoadCacheCommand(std::vector<std::string> const& args,
 {
   if (args.empty()) {
     status.SetError("called with wrong number of arguments.");
+    return false;
   }
 
   if (args.size() >= 2 && args[1] == "READ_WITH_PREFIX") {
     return ReadWithPrefix(args, status);
   }
 
+  if (status.GetMakefile().GetCMakeInstance()->GetWorkingMode() ==
+      cmake::SCRIPT_MODE) {
+    status.SetError(
+      "Only load_cache(READ_WITH_PREFIX) may be used in script mode");
+    return false;
+  }
+
   // Cache entries to be excluded from the import list.
   // If this set is empty, all cache entries are brought in
   // and they can not be overridden.

Tests/RunCMake/CMakeLists.txt

@@ -279,6 +279,7 @@ add_RunCMake_test(include)
 add_RunCMake_test(include_directories)
 add_RunCMake_test(include_guard)
 add_RunCMake_test(list)
+add_RunCMake_test(load_cache)
 add_RunCMake_test(math)
 add_RunCMake_test(message)
 add_RunCMake_test(option)

Tests/RunCMake/load_cache/CMakeLists.txt

+cmake_minimum_required(VERSION 3.16)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/load_cache/NewForm_Project.cmake

+load_cache(${CMAKE_CURRENT_BINARY_DIR}/../test_project READ_WITH_PREFIX LOAD_CACHE_TEST_
+  CACHE_STRING
+  CACHE_BOOL
+  CACHE_INTERNAL)
+
+if(NOT LOAD_CACHE_TEST_CACHE_STRING STREQUAL "cache string")
+  message(FATAL_ERROR "CACHE_STRING: was ${CACHE_STRING}, expected \"cache string\"")
+endif()
+
+if(NOT LOAD_CACHE_TEST_CACHE_BOOL)
+  message(FATAL_ERROR "CACHE_BOOL: was falsey, expected ON")
+endif()
+
+if(NOT LOAD_CACHE_TEST_CACHE_INTERNAL STREQUAL "cache internal")
+  message(FATAL_ERROR "CACHE_INTERNAL: was ${CACHE_INTENRAL}, expected \"cache internal\"")
+endif()

Tests/RunCMake/load_cache/NewForm_Script.cmake

+load_cache(${RunCMake_BINARY_DIR}/test_project READ_WITH_PREFIX LOAD_CACHE_TEST_
+  CACHE_STRING
+  CACHE_BOOL
+  CACHE_INTERNAL)
+
+if(NOT LOAD_CACHE_TEST_CACHE_STRING STREQUAL "cache string")
+  message(FATAL_ERROR "CACHE_STRING: was ${CACHE_STRING}, expected \"cache string\"")
+endif()
+
+if(NOT LOAD_CACHE_TEST_CACHE_BOOL)
+  message(FATAL_ERROR "CACHE_BOOL: was falsey, expected ON")
+endif()
+
+if(NOT LOAD_CACHE_TEST_CACHE_INTERNAL STREQUAL "cache internal")
+  message(FATAL_ERROR "CACHE_INTERNAL: was ${CACHE_INTENRAL}, expected \"cache internal\"")
+endif()

Tests/RunCMake/load_cache/OldForm_Script-result.txt

+1

Tests/RunCMake/load_cache/OldForm_Script-stderr.txt

+^CMake Error at.*/Tests/RunCMake/load_cache/OldForm_Script.cmake:1 \(load_cache\):
+  load_cache Only load_cache\(READ_WITH_PREFIX\) may be used in script mode$

Tests/RunCMake/load_cache/OldForm_Script.cmake

+load_cache(${RunCMake_BINARY_DIR}/test_project INCLUDE_INTERNALS CACHE_INTERNAL)
+
+if(NOT CACHE_STRING STREQUAL "cache string")
+  message(FATAL_ERROR "CACHE_STRING: was ${CACHE_STRING}, expected \"cache string\"")
+endif()
+
+if(NOT CACHE_BOOL)
+  message(FATAL_ERROR "CACHE_BOOL: was falsey, expected ON")
+endif()
+
+if(NOT CACHE_INTERNAL STREQUAL "cache internal")
+  message(FATAL_ERROR "CACHE_INTERNAL: was ${CACHE_INTENRAL}, expected \"cache internal\"")
+endif()

Tests/RunCMake/load_cache/RunCMakeTest.cmake

+include(RunCMake)
+
+file(WRITE ${RunCMake_BINARY_DIR}/test_project/CMakeCache.txt [[
+CACHE_STRING:STRING=cache string
+CACHE_BOOL:BOOL=ON
+CACHE_INTERNAL:INTERNAL=cache internal
+]])
+
+run_cmake(NewForm_Project)
+run_cmake_command(NewForm_Script ${CMAKE_COMMAND} -DRunCMake_BINARY_DIR=${RunCMake_BINARY_DIR}
+  -P "${RunCMake_SOURCE_DIR}/NewForm_Script.cmake")
+run_cmake_command(OldForm_Script ${CMAKE_COMMAND} -DRunCMake_BINARY_DIR=${RunCMake_BINARY_DIR}
+  -P "${RunCMake_SOURCE_DIR}/OldForm_Script.cmake")