How about a new emerge flag that prevents installations which require manual install, or a flag that interrupts a series of emerges (such as result from emerge -uD world) before installing a package that requires manual action? The user would be warned that the next package will require manual intervention, then they would OK the installation of that package, and the emerge would stop after that package gets installed. I realize that extra information might need to be added to package definitions in order for this to work. The recent change to httpd's file layout b0rked our servers and we could have controlled the process better with this capability.
Steps to Reproduce:
There is no line - at least that I can see - to define whether an update will require modification to system settings or not. In your case, an upgrade of apache from version X to version Y caused you problems and a similar upgrade from version X to version Z would to, but if Y to Z doesn't cause problems then how should Z be marked? If you can see a way to do it cleanly, feel free to bring it up for discussion on the email@example.com mailing list. However, it's never a good idea to upgrade servers that are in use anyway.
*** Bug 140682 has been marked as a duplicate of this bug. ***