The find_dependency() macro wraps a find_package() call for
a package dependency:
find_dependency(<dep> [...])
It is designed to be used in a
Package Configuration File
(<PackageName>Config.cmake). find_dependency forwards the correct
parameters for QUIET and REQUIRED which were passed to
the original find_package() call. Any additional arguments
specified are forwarded to find_package().
If the dependency could not be found it sets an informative diagnostic
message and calls return() to end processing of the calling
package configuration file and return to the find_package()
command that loaded it.
Note
The call to return() makes this macro unsuitable to call
from Find Modules.
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 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.
Changed in version 3.15: Previously, the underlying call to 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.
Changed in version 3.26: The pre-3.15 optimization was restored, but with the above-described
heuristic to account for varying find_dependency call arguments.