diff options
| -rw-r--r-- | Modules/CMakeFindDependencyMacro.cmake | 85 | ||||
| -rw-r--r-- | Tests/RunCMake/find_dependency/transitive-stdout.txt | 5 |
2 files changed, 59 insertions, 31 deletions
diff --git a/Modules/CMakeFindDependencyMacro.cmake b/Modules/CMakeFindDependencyMacro.cmake index 921333b..2c04abe 100644 --- a/Modules/CMakeFindDependencyMacro.cmake +++ b/Modules/CMakeFindDependencyMacro.cmake @@ -3,7 +3,7 @@ #[=======================================================================[.rst: CMakeFindDependencyMacro -------------------------- +------------------------ .. command:: find_dependency @@ -28,37 +28,70 @@ CMakeFindDependencyMacro The call to :command:`return` makes this macro unsuitable to call from :ref:`Find Modules`. + +Package Dependency Search Optimizations +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +If ``find_dependency`` is called with arguments identical to a previous +call in the same directory, perhaps due to diamond-shaped package +dependencies, the underlying call to :command:`find_package` is optimized +out. This optimization is important to support large package dependency +graphs while avoiding a combinatorial explosion of repeated searches. +However, the heuristic cannot account for ambient variables that +affect package behavior, such as ``<PackageName>_USE_STATIC_LIBS``, +offered by some packages. Therefore package configuration files should +avoid setting such variables before their calls to ``find_dependency``. + +.. versionchanged:: 3.15 + Previously, the underlying call to :command:`find_package` was always + optimized out if the package had already been found. CMake 3.15 + removed the optimization to support cases in which ``find_dependency`` + call arguments request different components. + +.. versionchanged:: 3.26 + The pre-3.15 optimization was restored, but with the above-described + heuristic to account for varying ``find_dependency`` call arguments. + #]=======================================================================] macro(find_dependency dep) - set(cmake_fd_quiet_arg) - if(${CMAKE_FIND_PACKAGE_NAME}_FIND_QUIETLY) - set(cmake_fd_quiet_arg QUIET) - endif() - set(cmake_fd_required_arg) - if(${CMAKE_FIND_PACKAGE_NAME}_FIND_REQUIRED) - set(cmake_fd_required_arg REQUIRED) - endif() + string(SHA256 cmake_fd_call_hash "${dep};${ARGN};${${CMAKE_FIND_PACKAGE_NAME}_FIND_REQUIRED}") + if(_CMAKE_${dep}_${cmake_fd_call_hash}_FOUND) + unset(cmake_fd_call_hash) + else() + list(APPEND _CMAKE_${dep}_HASH_STACK ${cmake_fd_call_hash}) + set(cmake_fd_quiet_arg) + if(${CMAKE_FIND_PACKAGE_NAME}_FIND_QUIETLY) + set(cmake_fd_quiet_arg QUIET) + endif() + set(cmake_fd_required_arg) + if(${CMAKE_FIND_PACKAGE_NAME}_FIND_REQUIRED) + set(cmake_fd_required_arg REQUIRED) + endif() - get_property(cmake_fd_alreadyTransitive GLOBAL PROPERTY - _CMAKE_${dep}_TRANSITIVE_DEPENDENCY - ) + get_property(cmake_fd_alreadyTransitive GLOBAL PROPERTY + _CMAKE_${dep}_TRANSITIVE_DEPENDENCY + ) - find_package(${dep} ${ARGN} - ${cmake_fd_quiet_arg} - ${cmake_fd_required_arg} - ) + find_package(${dep} ${ARGN} + ${cmake_fd_quiet_arg} + ${cmake_fd_required_arg} + ) + list(POP_BACK _CMAKE_${dep}_HASH_STACK cmake_fd_call_hash) + set("_CMAKE_${dep}_${cmake_fd_call_hash}_FOUND" "${${dep}_FOUND}") - if(NOT DEFINED cmake_fd_alreadyTransitive OR cmake_fd_alreadyTransitive) - set_property(GLOBAL PROPERTY _CMAKE_${dep}_TRANSITIVE_DEPENDENCY TRUE) - endif() + if(NOT DEFINED cmake_fd_alreadyTransitive OR cmake_fd_alreadyTransitive) + set_property(GLOBAL PROPERTY _CMAKE_${dep}_TRANSITIVE_DEPENDENCY TRUE) + endif() - unset(cmake_fd_alreadyTransitive) - unset(cmake_fd_quiet_arg) - unset(cmake_fd_required_arg) - if (NOT ${dep}_FOUND) - set(${CMAKE_FIND_PACKAGE_NAME}_NOT_FOUND_MESSAGE "${CMAKE_FIND_PACKAGE_NAME} could not be found because dependency ${dep} could not be found.") - set(${CMAKE_FIND_PACKAGE_NAME}_FOUND False) - return() + unset(cmake_fd_alreadyTransitive) + unset(cmake_fd_call_hash) + unset(cmake_fd_quiet_arg) + unset(cmake_fd_required_arg) + if (NOT ${dep}_FOUND) + set(${CMAKE_FIND_PACKAGE_NAME}_NOT_FOUND_MESSAGE "${CMAKE_FIND_PACKAGE_NAME} could not be found because dependency ${dep} could not be found.") + set(${CMAKE_FIND_PACKAGE_NAME}_FOUND False) + return() + endif() endif() endmacro() diff --git a/Tests/RunCMake/find_dependency/transitive-stdout.txt b/Tests/RunCMake/find_dependency/transitive-stdout.txt index 0f5b366..6fe40e9 100644 --- a/Tests/RunCMake/find_dependency/transitive-stdout.txt +++ b/Tests/RunCMake/find_dependency/transitive-stdout.txt @@ -4,11 +4,6 @@ -- Loading B with components: 'B1' -- Loading A with components: '' -- Loading C with components: '' --- Loading A with components: '' -- Loading D with components: '' --- Loading A with components: 'A1' -- Loading B with components: '' --- Loading A with components: '' --- Loading C with components: '' --- Loading A with components: '' -- end |