use-flags: Add note about USE flags for rdeps that don't change the package

diff --git a/general-concepts/use-flags/text.xml b/general-concepts/use-flags/text.xml
index a1cf2c4..3ca3aff 100644 (file)
--- a/general-concepts/use-flags/text.xml
+++ b/general-concepts/use-flags/text.xml
@@ -27,6 +27,14 @@
        break, among other issues.
 </p>
 
+<p>
+       The usage of a <c>USE</c> flag should not control runtime dependencies when
+       the package does not link to it. Doing so will create extra
+       configuration for the package and re-compilation for no underlying file
+       change on disk. This should be avoided and instead can be conveyed to the
+       user via post install messages if needed.
+</p>
+
 <note>
        The status of USE flags is saved in the VDB, and their value in
        <c>pkg_prerm</c> and <c>pkg_postrm</c> is taken from there. This means that