fb9a3d0c7d
Since commit 37da6af17d (find_dependency: Always search dependencies,
2019-03-29, v3.15.0-rc1~301^2) we search for a package every time it is
encountered in the transitive dependency graph traversal, even if it has
been found before. This was done in case a new visit to a given package
requests different components than a previous visit. However, it also
causes a lot of repeat processing that is unnecessary in the common case
that all calls share the same set of components (often none).
Restore the logic to avoid repeating the search for an already-found
package. Handle differences in components by de-duplicating based on
the complete `find_package` call arguments.
Fixes: #23685
98 lines
3.8 KiB
CMake
98 lines
3.8 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
|
|
# file Copyright.txt or https://cmake.org/licensing for details.
|
|
|
|
#[=======================================================================[.rst:
|
|
CMakeFindDependencyMacro
|
|
------------------------
|
|
|
|
.. command:: find_dependency
|
|
|
|
The ``find_dependency()`` macro wraps a :command:`find_package` call for
|
|
a package dependency::
|
|
|
|
find_dependency(<dep> [...])
|
|
|
|
It is designed to be used in a
|
|
:ref:`Package Configuration File <Config File Packages>`
|
|
(``<PackageName>Config.cmake``). ``find_dependency`` forwards the correct
|
|
parameters for ``QUIET`` and ``REQUIRED`` which were passed to
|
|
the original :command:`find_package` call. Any additional arguments
|
|
specified are forwarded to :command:`find_package`.
|
|
|
|
If the dependency could not be found it sets an informative diagnostic
|
|
message and calls :command:`return` to end processing of the calling
|
|
package configuration file and return to the :command:`find_package`
|
|
command that loaded it.
|
|
|
|
.. note::
|
|
|
|
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)
|
|
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
|
|
)
|
|
|
|
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()
|
|
|
|
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()
|