Skip to content

Mitigate ClangFormat max argument size #2592

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jviotti merged 2 commits into from
Jul 3, 2026
Merged

Mitigate ClangFormat max argument size #2592

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
484018f
Mitigate ClangFormat max argument size
jviotti Jul 3, 2026
7d64593
More
jviotti Jul 3, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
56 changes: 51 additions & 5 deletions cmake/common/targets/clang-format.cmake
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -101,6 +101,12 @@ function(sourcemeta_target_clang_format)
file(GLOB_RECURSE SOURCEMETA_TARGET_CLANG_FORMAT_FILES
${SOURCEMETA_TARGET_CLANG_FORMAT_SOURCES})

# Fail fast rather than silently skipping formatting, since batching an empty
# file list would otherwise produce targets that do nothing but succeed
if(NOT SOURCEMETA_TARGET_CLANG_FORMAT_FILES)
message(FATAL_ERROR "The ClangFormat file globs did not match any files")
endif()

set(CLANG_FORMAT_CONFIG "${CMAKE_CURRENT_FUNCTION_LIST_DIR}/clang-format.json")
if(CMAKE_SYSTEM_NAME STREQUAL "MSYS")
# Because `clang-format` is typically a Windows `.exe`, transform the path accordingly
Expand All @@ -110,18 +116,58 @@ function(sourcemeta_target_clang_format)

if(CLANG_FORMAT_BIN)
message(STATUS "Using `clang-format` from ${CLANG_FORMAT_BIN}")

# Invoke `clang-format` over the files in batches whose combined argument
# length is bounded well below the operating system command-line length
# limit (notably the Windows `CreateProcess` limit of around 32767
# characters), so the command stays runnable however many sources exist and
# however long their paths are
set(SOURCEMETA_CLANG_FORMAT_BATCH_LIMIT 8000)
set(SOURCEMETA_CLANG_FORMAT_COMMANDS)
set(SOURCEMETA_CLANG_FORMAT_TEST_COMMANDS)
set(SOURCEMETA_CLANG_FORMAT_BATCH)
set(SOURCEMETA_CLANG_FORMAT_BATCH_LENGTH 0)
foreach(SOURCEMETA_CLANG_FORMAT_FILE IN LISTS
SOURCEMETA_TARGET_CLANG_FORMAT_FILES)
string(LENGTH "${SOURCEMETA_CLANG_FORMAT_FILE}"
SOURCEMETA_CLANG_FORMAT_FILE_LENGTH)
math(EXPR SOURCEMETA_CLANG_FORMAT_NEXT_LENGTH
"${SOURCEMETA_CLANG_FORMAT_BATCH_LENGTH} + ${SOURCEMETA_CLANG_FORMAT_FILE_LENGTH} + 1")
# Flush the current batch before it would cross the bound, keeping at
# least one file per batch so an unusually long path still makes progress
if(SOURCEMETA_CLANG_FORMAT_BATCH AND SOURCEMETA_CLANG_FORMAT_NEXT_LENGTH
GREATER SOURCEMETA_CLANG_FORMAT_BATCH_LIMIT)
list(APPEND SOURCEMETA_CLANG_FORMAT_COMMANDS
COMMAND "${CLANG_FORMAT_BIN}" "--style=file:${CLANG_FORMAT_CONFIG}"
-i ${SOURCEMETA_CLANG_FORMAT_BATCH})
list(APPEND SOURCEMETA_CLANG_FORMAT_TEST_COMMANDS
COMMAND "${CLANG_FORMAT_BIN}" "--style=file:${CLANG_FORMAT_CONFIG}"
--dry-run -Werror -i ${SOURCEMETA_CLANG_FORMAT_BATCH})
set(SOURCEMETA_CLANG_FORMAT_BATCH)
set(SOURCEMETA_CLANG_FORMAT_BATCH_LENGTH 0)
endif()
list(APPEND SOURCEMETA_CLANG_FORMAT_BATCH "${SOURCEMETA_CLANG_FORMAT_FILE}")
math(EXPR SOURCEMETA_CLANG_FORMAT_BATCH_LENGTH
"${SOURCEMETA_CLANG_FORMAT_BATCH_LENGTH} + ${SOURCEMETA_CLANG_FORMAT_FILE_LENGTH} + 1")
endforeach()
if(SOURCEMETA_CLANG_FORMAT_BATCH)
list(APPEND SOURCEMETA_CLANG_FORMAT_COMMANDS
COMMAND "${CLANG_FORMAT_BIN}" "--style=file:${CLANG_FORMAT_CONFIG}"
-i ${SOURCEMETA_CLANG_FORMAT_BATCH})
list(APPEND SOURCEMETA_CLANG_FORMAT_TEST_COMMANDS
COMMAND "${CLANG_FORMAT_BIN}" "--style=file:${CLANG_FORMAT_CONFIG}"
--dry-run -Werror -i ${SOURCEMETA_CLANG_FORMAT_BATCH})
endif()

add_custom_target(clang_format
WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"
VERBATIM
COMMAND "${CLANG_FORMAT_BIN}" "--style=file:${CLANG_FORMAT_CONFIG}"
-i ${SOURCEMETA_TARGET_CLANG_FORMAT_FILES}
${SOURCEMETA_CLANG_FORMAT_COMMANDS}
Comment thread
cubic-dev-ai[bot] marked this conversation as resolved.
Comment thread
jviotti marked this conversation as resolved.
COMMENT "Formatting sources using ClangFormat")
add_custom_target(clang_format_test
WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"
VERBATIM
COMMAND "${CLANG_FORMAT_BIN}" "--style=file:${CLANG_FORMAT_CONFIG}"
--dry-run -Werror
-i ${SOURCEMETA_TARGET_CLANG_FORMAT_FILES}
${SOURCEMETA_CLANG_FORMAT_TEST_COMMANDS}
COMMENT "Checking for ClangFormat compliance")
else()
add_custom_target(clang_format
Expand Down
Loading