Overhaul how we search for clang-format (#4888)

Co-authored-by: Casey Carter <[email protected]>

Author: StephanTLavavej

tools/format/CMakeLists.txt

@@ -4,76 +4,68 @@
 cmake_minimum_required(VERSION 3.29.0)
 project(msvc_standard_libraries_format NONE)
 
-set(did_search OFF)
-
-if(NOT DEFINED CLANG_FORMAT)
-    message(STATUS "Searching for VS clang-format")
-    set(did_search ON)
-endif()
-
-if(PROJECT_IS_TOP_LEVEL)
-    set(message_level FATAL_ERROR)
-else()
-    set(message_level WARNING)
-endif()
-
 find_program(CLANG_FORMAT
     NAMES clang-format
-    PATHS "C:/Program Files/Microsoft Visual Studio/2022/Preview/VC/Tools/Llvm/bin"
+    HINTS "$ENV{VCINSTALLDIR}/Tools/Llvm/x64/bin"
     DOC "The clang-format program to use"
-    NO_DEFAULT_PATH
-    NO_CMAKE_PATH
-    NO_CMAKE_ENVIRONMENT_PATH
-    NO_SYSTEM_ENVIRONMENT_PATH
-    NO_CMAKE_SYSTEM_PATH
+    REQUIRED
 )
 
-if(CLANG_FORMAT)
-    if(did_search)
-        message(STATUS "Searching for VS clang-format - found")
-    endif()
+execute_process(
+    COMMAND "${CLANG_FORMAT}" --version
+    OUTPUT_VARIABLE clang_format_version
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+)
 
-    file(GLOB_RECURSE maybe_clang_format_files
-        "../../benchmarks/inc/*"
-        "../../benchmarks/src/*"
-        "../../stl/inc/*"
-        "../../stl/modules/*"
-        "../../stl/src/*"
-        "../../tests/*"
-        "../../tools/*"
-    )
-    set(clang_format_files "")
+if(clang_format_version MATCHES "clang-format version ([0-9]+\.[0-9]+\.[0-9]+)")
+    set(expected_version "17.0.3")
+    if(CMAKE_MATCH_1 VERSION_LESS expected_version)
+        message(FATAL_ERROR "Found clang-format ${CMAKE_MATCH_1}, older than expected ${expected_version}.")
+    elseif(CMAKE_MATCH_1 VERSION_EQUAL expected_version)
+        message(STATUS "Found clang-format ${CMAKE_MATCH_1}.")
+    elseif(CMAKE_MATCH_1 VERSION_GREATER expected_version)
+        message(WARNING "Found clang-format ${CMAKE_MATCH_1}, newer than expected ${expected_version}.")
+    endif()
+else()
+    message(FATAL_ERROR "Unexpected `clang-format --version` output: '${clang_format_version}'")
+endif()
 
-    foreach(maybe_file IN LISTS maybe_clang_format_files)
-        cmake_path(GET maybe_file FILENAME filename)
-        cmake_path(GET maybe_file EXTENSION LAST_ONLY extension)
+file(GLOB_RECURSE maybe_clang_format_files
+    "../../benchmarks/inc/*"
+    "../../benchmarks/src/*"
+    "../../stl/inc/*"
+    "../../stl/modules/*"
+    "../../stl/src/*"
+    "../../tests/*"
+    "../../tools/*"
+)
+set(clang_format_files "")
 
-        if(extension MATCHES [[^(|\.cpp|\.h|\.hpp|\.ixx)$]] AND NOT filename MATCHES [[^\.]])
-            list(APPEND clang_format_files "${maybe_file}")
-        endif()
-    endforeach()
+foreach(maybe_file IN LISTS maybe_clang_format_files)
+    cmake_path(GET maybe_file FILENAME filename)
+    cmake_path(GET maybe_file EXTENSION LAST_ONLY extension)
 
-    if(NOT clang_format_files)
-        message("${message_level}" "Could not find any files to clang-format!")
+    if(extension MATCHES [[^(|\.cpp|\.h|\.hpp|\.ixx)$]] AND NOT filename MATCHES [[^\.]])
+        list(APPEND clang_format_files "${maybe_file}")
     endif()
+endforeach()
 
-    add_custom_target(run-format)
-
-    foreach(file IN LISTS clang_format_files)
-        cmake_path(RELATIVE_PATH file
-            BASE_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../.."
-            OUTPUT_VARIABLE relative-file
-        )
-        string(REPLACE "/" "_" relative-file "${relative-file}")
-        set(target_name "clang-format.${relative-file}")
-        add_custom_target("${target_name}"
-            COMMAND "${CLANG_FORMAT}" -style=file -i "${file}"
-            WORKING_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../.."
-        )
-        add_dependencies(run-format "${target_name}")
-    endforeach()
-else()
-    if(did_search)
-        message("${message_level}" "Searching for VS clang-format - not found.")
-    endif()
+if(NOT clang_format_files)
+    message(FATAL_ERROR "Could not find any files to clang-format!")
 endif()
+
+add_custom_target(run-format)
+
+foreach(file IN LISTS clang_format_files)
+    cmake_path(RELATIVE_PATH file
+        BASE_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../.."
+        OUTPUT_VARIABLE relative-file
+    )
+    string(REPLACE "/" "_" relative-file "${relative-file}")
+    set(target_name "clang-format.${relative-file}")
+    add_custom_target("${target_name}"
+        COMMAND "${CLANG_FORMAT}" -style=file -i "${file}"
+        WORKING_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../.."
+    )
+    add_dependencies(run-format "${target_name}")
+endforeach()