The pro2cmake.py conversion script faithfully reproduced the .pro files
for the plugins, which specified the libraries as public. But in CMake,
the implications of this are that public usage requirements should then
be propagated to consumers. We don't expect any consumers, since a
plugin is created as a MODULE library in CMake, so for Windows we don't
even have an import library to link with. The only exception to this is
for static builds where plugins are created as STATIC libraries
instead, but only in certain controlled situations do we then link to
plugins. Even then, usage requirements are not expected to propagate to
the consumers, so these relationships should always be specified as
private.
This change warns on any PUBLIC usage requirements specified for a
plugin. This check is disabled by default to avoid spamming CI builds
for repos that haven't been fixed yet. The check can be enabled by a
CMake cache option, which is intended for developers to use locally
when fixing this issue in other repos (all plugins in qtbase should
not trigger this warning as a result of changes in this commit).
Task-number: QTBUG-90819
Pick-to: 6.1
Change-Id: I09f2c8da77db1193ad3370f85d367dfc6ab7b9a6
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
fe29159aad