cmake-presets: Introduce toolchainFile preset option

In v3 of the presets, the `--toolchain` command line argument now
has a preset mapping.

Help/manual/cmake-presets.7.rst

@@ -182,6 +182,14 @@ that may contain the following fields:
       ignore the field, but the IDE can use them to set up the environment
       before invoking CMake.
 
+``toolchainFile``
+
+  An optional string representing the path to the toolchain file.
+  This field supports `macro expansion`_. If a relative path is specified,
+  it is calculated relative to the build directory, and if not found,
+  relative to the source directory. Takes precedence over any `CMAKE_TOOLCHAIN_FILE`
+  value. This is allowed in preset files specifying version ``3`` or above.
+
 ``binaryDir``
 
   An optional string representing the path to the output binary directory.

Help/manual/presets/schema.json

@@ -87,6 +87,10 @@
             "type": "string",
             "description": "An optional string representing the generator to use for the preset. If generator is not specified, the normal generator discovery procedure is used. Note that for Visual Studio generators, unlike in the command line -G argument, you cannot include the platform name in the generator name. Use the architecture field instead."
           },
+          "toolchainFile": {
+            "type": "string",
+            "description": "An optional string representing the path to the toolchain file. This field supports macro expansion. If a relative path is specified, it is calculated relative to the build directory, and if not found, relative to the source directory."
+          },
           "installDir": {
             "type": "string",
             "description": "An optional string representing the path to the output binary directory. This field supports macro expansion. If a relative path is specified, it is calculated relative to the source directory. If binaryDir is not specified, it must be inherited from the inherits preset (unless this preset is hidden)."
@@ -360,6 +364,7 @@
           "generator": {},
           "architecture": {},
           "toolset": {},
+          "toolchainFile": {},
           "binaryDir": {},
           "installDir": {},
           "cmakeExecutable": {},

Source/cmCMakePresetsFile.cxx

@@ -214,6 +214,12 @@ bool ExpandMacros(const cmCMakePresetsFile& file,
     cmSystemTools::ConvertToUnixSlashes(out->InstallDir);
   }
 
+  if (!preset.ToolchainFile.empty()) {
+    std::string toolchain = preset.ToolchainFile;
+    CHECK_EXPAND(out, toolchain, macroExpanders, file.GetVersion(preset))
+    out->ToolchainFile = toolchain;
+  }
+
   for (auto& variable : out->CacheVariables) {
     if (variable.second) {
       CHECK_EXPAND(out, variable.second->Value, macroExpanders,
@@ -643,6 +649,7 @@ cmCMakePresetsFile::ConfigurePreset::VisitPresetInherit(
   }
   InheritString(preset.BinaryDir, parent.BinaryDir);
   InheritString(preset.InstallDir, parent.InstallDir);
+  InheritString(preset.ToolchainFile, parent.ToolchainFile);
   InheritOptionalValue(preset.WarnDev, parent.WarnDev);
   InheritOptionalValue(preset.ErrorDev, parent.ErrorDev);
   InheritOptionalValue(preset.WarnDeprecated, parent.WarnDeprecated);
@@ -989,6 +996,9 @@ const char* cmCMakePresetsFile::ResultToString(ReadFileResult result)
       return "Invalid preset condition";
     case ReadFileResult::CONDITION_UNSUPPORTED:
       return "File version must be 3 or higher for condition support";
+    case ReadFileResult::TOOLCHAIN_FILE_UNSUPPORTED:
+      return "File version must be 3 or higher for toolchainFile preset "
+             "support.";
   }
 
   return "Unknown error";

Source/cmCMakePresetsFile.h

@@ -39,6 +39,7 @@ public:
     INSTALL_PREFIX_UNSUPPORTED,
     INVALID_CONDITION,
     CONDITION_UNSUPPORTED,
+    TOOLCHAIN_FILE_UNSUPPORTED,
   };
 
   enum class ArchToolsetStrategy
@@ -113,6 +114,7 @@ public:
     cm::optional<ArchToolsetStrategy> ArchitectureStrategy;
     std::string Toolset;
     cm::optional<ArchToolsetStrategy> ToolsetStrategy;
+    std::string ToolchainFile;
     std::string BinaryDir;
     std::string InstallDir;
 

Source/cmCMakePresetsFileReadJSON.cxx

@@ -491,6 +491,8 @@ auto const ConfigurePresetHelper =
           false)
     .Bind("architecture"_s, ArchitectureHelper, false)
     .Bind("toolset"_s, ToolsetHelper, false)
+    .Bind("toolchainFile"_s, &ConfigurePreset::ToolchainFile,
+          PresetStringHelper, false)
     .Bind("binaryDir"_s, &ConfigurePreset::BinaryDir, PresetStringHelper,
           false)
     .Bind("installDir"_s, &ConfigurePreset::InstallDir, PresetStringHelper,
@@ -973,6 +975,11 @@ cmCMakePresetsFile::ReadFileResult cmCMakePresetsFile::ReadJSONFile(
       return ReadFileResult::CONDITION_UNSUPPORTED;
     }
 
+    // Support for toolchainFile presets added in version 3.
+    if (v < 3 && !preset.ToolchainFile.empty()) {
+      return ReadFileResult::TOOLCHAIN_FILE_UNSUPPORTED;
+    }
+
     this->ConfigurePresetOrder.push_back(preset.Name);
   }
 

Source/cmake.cxx

@@ -1257,6 +1257,13 @@ void cmake::SetArgs(const std::vector<std::string>& args)
         "PATH", expandedPreset->InstallDir
       };
     }
+    if (!expandedPreset->ToolchainFile.empty() &&
+        this->State->GetInitializedCacheValue("CMAKE_TOOLCHAIN_FILE") ==
+          nullptr) {
+      this->UnprocessedPresetVariables["CMAKE_TOOLCHAIN_FILE"] = {
+        "FILEPATH", expandedPreset->ToolchainFile
+      };
+    }
 
     if (!expandedPreset->ArchitectureStrategy ||
         expandedPreset->ArchitectureStrategy ==

Tests/RunCMake/CMakePresets/FuturePresetToolchainField-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/CMakePresets/FuturePresetToolchainField-stderr.txt

@@ -0,0 +1,2 @@
+^CMake Error: Could not read presets from [^
+]*/Tests/RunCMake/CMakePresets/FuturePresetToolchainField: File version must be 3 or higher for toolchainFile preset support.$

Tests/RunCMake/CMakePresets/FuturePresetToolchainField.json.in

@@ -0,0 +1,11 @@
+{
+  "version": 1,
+  "configurePresets": [
+    {
+      "name": "FuturePresetToolchainField",
+      "generator": "@RunCMake_GENERATOR@",
+      "binaryDir": "${sourceDir}/build",
+      "toolchainFile": "${sourceDir}/toolchain.cmake"
+    }
+  ]
+}

Tests/RunCMake/CMakePresets/GoodToolchain.json.in

@@ -0,0 +1,30 @@
+{
+    "version": 3,
+    "configurePresets": [
+        {
+            "name": "GoodToolchainDefault",
+            "generator": "@RunCMake_GENERATOR@",
+            "binaryDir": "${sourceDir}/build/${presetName}",
+            "toolchainFile": "${sourceDir}/toolchain.cmake"
+        },
+        {
+            "name": "GoodToolchainInherit",
+            "inherits": "GoodToolchainDefault",
+            "cacheVariables": {
+                "CMAKE_TOOLCHAIN_FILE": {
+                "type": "FILEPATH",
+                "value": "${sourceDir}/toolchain_bad.cmake"
+                }
+            }
+        },
+        {
+            "name": "GoodToolchainOverride",
+            "inherits": "GoodToolchainInherit",
+            "toolchainFile": "override_toolchain.cmake"
+        },
+        {
+            "name": "GoodToolchainCommandLine",
+            "inherits": "GoodToolchainOverride"
+        }
+    ]
+}

Tests/RunCMake/CMakePresets/GoodToolchainCommandLine.cmake

@@ -0,0 +1,3 @@
+include("${RunCMake_SOURCE_DIR}/TestVariable.cmake")
+
+test_variable("CMAKE_TOOLCHAIN_FILE" "FILEPATH" "${CMAKE_SOURCE_DIR}/cmd_line_toolchain.cmake")

Tests/RunCMake/CMakePresets/GoodToolchainDefault.cmake

@@ -0,0 +1,3 @@
+include("${RunCMake_SOURCE_DIR}/TestVariable.cmake")
+
+test_variable("CMAKE_TOOLCHAIN_FILE" "FILEPATH" "${CMAKE_SOURCE_DIR}/toolchain.cmake")

Tests/RunCMake/CMakePresets/GoodToolchainInherit.cmake

@@ -0,0 +1,3 @@
+include("${RunCMake_SOURCE_DIR}/TestVariable.cmake")
+
+test_variable("CMAKE_TOOLCHAIN_FILE" "FILEPATH" "${CMAKE_SOURCE_DIR}/toolchain.cmake")

Tests/RunCMake/CMakePresets/GoodToolchainOverride.cmake

@@ -0,0 +1,3 @@
+include("${RunCMake_SOURCE_DIR}/TestVariable.cmake")
+
+test_variable("CMAKE_TOOLCHAIN_FILE" "FILEPATH" "${CMAKE_SOURCE_DIR}/override_toolchain.cmake")

Tests/RunCMake/CMakePresets/RunCMakeTest.cmake

@@ -11,14 +11,23 @@ set(RunCMake-check-file check.cmake)
 
 include("${RunCMake_SOURCE_DIR}/validate_schema.cmake")
 
+function(reset_cmake_presets_directory name)
+  set(RunCMake_TEST_SOURCE_DIR "${RunCMake_BINARY_DIR}/${name}")
+  file(REMOVE_RECURSE "${RunCMake_TEST_SOURCE_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_SOURCE_DIR}")
+endfunction()
+
 function(run_cmake_presets name)
   set(RunCMake_TEST_SOURCE_DIR "${RunCMake_BINARY_DIR}/${name}")
   set(_source_arg "${RunCMake_TEST_SOURCE_DIR}")
   if(CMakePresets_SOURCE_ARG)
     set(_source_arg "${CMakePresets_SOURCE_ARG}")
   endif()
-  file(REMOVE_RECURSE "${RunCMake_TEST_SOURCE_DIR}")
-  file(MAKE_DIRECTORY "${RunCMake_TEST_SOURCE_DIR}")
+
+  if(NOT RunCMake_TEST_SOURCE_DIR_NO_CLEAN)
+    file(REMOVE_RECURSE "${RunCMake_TEST_SOURCE_DIR}")
+    file(MAKE_DIRECTORY "${RunCMake_TEST_SOURCE_DIR}")
+  endif()
   configure_file("${RunCMake_SOURCE_DIR}/CMakeLists.txt.in" "${RunCMake_TEST_SOURCE_DIR}/CMakeLists.txt" @ONLY)
 
   if(NOT CMakePresets_FILE)
@@ -95,6 +104,7 @@ run_cmake_presets(ExtraRootField)
 run_cmake_presets(ExtraPresetField)
 run_cmake_presets(ExtraVariableField)
 run_cmake_presets(FuturePresetInstallDirField)
+run_cmake_presets(FuturePresetToolchainField)
 run_cmake_presets(InvalidPresetVendor)
 set(CMakePresets_SCHEMA_EXPECTED_RESULT 0)
 run_cmake_presets(DuplicatePresets)
@@ -191,6 +201,28 @@ run_cmake_presets(GoodInstallInherit)
 run_cmake_presets(GoodInstallOverride)
 run_cmake_presets(GoodInstallCommandLine  "--install-prefix=${RunCMake_SOURCE_DIR}/path/passed/on/command_line")
 
+set(RunCMake_TEST_SOURCE_DIR_NO_CLEAN 1)
+set(CMakePresets_FILE "${RunCMake_SOURCE_DIR}/GoodToolchain.json.in")
+
+reset_cmake_presets_directory(GoodToolchainInherit)
+file(WRITE "${RunCMake_BINARY_DIR}/GoodToolchainDefault/toolchain.cmake" "")
+run_cmake_presets(GoodToolchainDefault)
+
+reset_cmake_presets_directory(GoodToolchainInherit)
+file(WRITE "${RunCMake_BINARY_DIR}/GoodToolchainInherit/toolchain.cmake" "")
+run_cmake_presets(GoodToolchainInherit)
+
+reset_cmake_presets_directory(GoodToolchainOverride)
+file(WRITE "${RunCMake_BINARY_DIR}/GoodToolchainOverride/override_toolchain.cmake" "")
+run_cmake_presets(GoodToolchainOverride)
+
+reset_cmake_presets_directory(GoodToolchainCommandLine)
+file(WRITE "${RunCMake_BINARY_DIR}/GoodToolchainCommandLine/cmd_line_toolchain.cmake" "")
+run_cmake_presets(GoodToolchainCommandLine  "--toolchain=${RunCMake_BINARY_DIR}/GoodToolchainCommandLine/cmd_line_toolchain.cmake")
+
+unset(RunCMake_TEST_SOURCE_DIR_NO_CLEAN)
+
+
 set(CMakePresets_FILE "${RunCMake_SOURCE_DIR}/CMakePresets.json.in")
 # Test bad preset arguments
 run_cmake_presets(VendorMacro)