Help/policy/CMP0166.rst

CMP0166
-------

.. versionadded:: 3.30

:genex:`TARGET_PROPERTY` evaluates link properties transitively over private
dependencies of static libraries.

In CMake 3.29 and below, the :genex:`TARGET_PROPERTY` generator expression
evaluates properties :prop_tgt:`INTERFACE_LINK_OPTIONS`,
:prop_tgt:`INTERFACE_LINK_DIRECTORIES`, and :prop_tgt:`INTERFACE_LINK_DEPENDS`
as if they were :ref:`Transitive Compile Properties` rather than
:ref:`Transitive Link Properties`, even when policy :policy:`CMP0099` is
set to ``NEW``.  Private dependencies of static libraries, which appear in
their :prop_tgt:`INTERFACE_LINK_LIBRARIES` guarded by :genex:`LINK_ONLY`
generator expressions, are not followed.  This is inconsistent with
evaluation of the same target properties during buildsystem generation.

CMake 3.30 and above prefer that :genex:`TARGET_PROPERTY` evaluates
properties :prop_tgt:`INTERFACE_LINK_OPTIONS`,
:prop_tgt:`INTERFACE_LINK_DIRECTORIES`, and :prop_tgt:`INTERFACE_LINK_DEPENDS`
as :ref:`Transitive Link Properties` such that private dependencies of static
libraries, which appear in their :prop_tgt:`INTERFACE_LINK_LIBRARIES` guarded
by :genex:`LINK_ONLY` generator expressions, are followed.
This policy provides compatibility for projects that have not been updated
to expect the new behavior.

The ``OLD`` behavior for this policy is for :genex:`TARGET_PROPERTY` to
evaluate properties :prop_tgt:`INTERFACE_LINK_OPTIONS`,
:prop_tgt:`INTERFACE_LINK_DIRECTORIES`, and :prop_tgt:`INTERFACE_LINK_DEPENDS`
as if they were :ref:`Transitive Compile Properties` by not following private
dependencies of static libraries.  The ``NEW`` behavior for this policy is
to evaluate them as :ref:`Transitive Link Properties` by following private
dependencies of static libraries.

.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 3.30
.. |WARNS_OR_DOES_NOT_WARN| replace:: does *not* warn
.. include:: include/STANDARD_ADVICE.rst

.. include:: include/DEPRECATED.rst