kcrash core pattern raising in 5.27+

[Harald Sitter]

Hola

Last week I added a new feature to kcrash which allows re-raising
terminal signals to the native core pattern handler process. Namely,
this allows system administrators to catch traces via coredump and
friends.

This feature is in addition to the existing drkonqi report mechanism
we have in place.

While this is currently opt-in, the plan is to have this be the
default behavior by 5.29. As such there are some UX concerns you may
have to deal with on a distribution level. I know that at least Fedora
and Kubuntu have a distribution crash aggregator set as default core
handler. While this is not a problem in of itself, you may wish to
review the UX implications of having drkonqi and raising into a distro
handler.

Actual example from Kubuntu: crashes aggregated by the apport core
handler will result in the apport UI reporting that something crashed
and asking if the user wishes to send the core dump to Canonical for
tracking, since this ultimately duplicates what drkonqi did (albeit on
a distro level) either drkonqi or the apport UI should be disabled or
a tight integration should be created [1].

So, I suggest you review if your distribution has a core handler by
default. And decide what you want to happen.

- If you cannot feasibly raise into that handler, explicitly set
-DKCRASH_CORE_PATTERN_RAISE=OFF (do note that this impairs sysadmin's
ability to use handlers, so if you find this necessary we should have
a talk about the specifics)

- If your handler has a UI attached to it, either do not install
drkonqi (all crashes will go through your handler UI this way) OR
don't show the handler UI on crashes out of kcrash (kcrash symbols
will the second to last frame of the current thread) OR form a unified
user experience as outlined in [1]. Until you are sure this is sorted
I'd also advise to explicitly set -DKCRASH_CORE_PATTERN_RAISE=OFF

- If none of the above applies and you either install coredump by
default or no handler by default you can enable this feature already
via -DKCRASH_CORE_PATTERN_RAISE=ON

[1] ex of integrated handling employed in kde4 times
https://community.kde.org/Kubuntu/QA/Whoopsie