Link line construction starts with `LINK_LIBRARIES` and appends
dependencies from the transitive closure of `INTERFACE_LINK_LIBRARIES`.
Only the entries of `LINK_LIBRARIES` are considered direct link
dependencies. In some advanced use cases, particularly involving static
libraries and static plugins, usage requirements need to update the list
of direct link dependencies. This may mean adding new items, removing
existing items, or both.
Add target properties to encode these usage requirements:
* INTERFACE_LINK_LIBRARIES_DIRECT
* INTERFACE_LINK_LIBRARIES_DIRECT_EXCLUDE
Fixes: #22496
Since commit 72e7c45e98 (Tests: Bump CMake minimum required in tests to
2.8.12, 2020-12-22, v3.20.0-rc1~224^2), policy CMP0022 is set to NEW for
the entire test. Remove a leftover explicit setting.
When an object library is used via `target_link_libraries`, any targets
listed in the object library's `INTERFACE_LINK_LIBRARIES` closure should
become direct dependencies of the consuming target. However, these were
accidentally left out by `cmComputeTargetDepends::CollectTargetDepends`
because object libraries are encountered through external object sources
first and then added to the `emitted` set which blocks them from being
processed as link dependencies.
This was not noticed by the test case in commit bab24e782c
(target_link_libraries: Propagate dependencies of object libraries,
2018-12-10, v3.14.0-rc1~260^2) because the relevant dependency appears
transitively through the object library target itself.
Re-order the logic to process link dependencies first, and then external
object sources. That way object libraries used via
`target_link_libraries` will be treated as such by dependency analysis.
This also adds missing backtrace information for object libraries used
via `target_link_libraries`. The missing information was mentioned in a
FIXME comment in the RunCMake.FileAPI test added by commit ea0a060168
(fileapi: Add test for codemodel v2, 2018-11-09, v3.14.0-rc1~257^2~7).
That comment itself was dropped by commit a0de350e2f (FileAPI test:
Break gen_check_targets() into JSON files, 2020-02-07), but we can now
update the corresponding location in the `.json` files to have the
now-expected backtrace information.
Fixes: #20421
Add the test case from commit bab24e782c (target_link_libraries:
Propagate dependencies of object libraries, 2018-12-10,
v3.14.0-rc1~260^2) to the main ObjectLibrary test.
