Am 30.09.2019 um 18:26 hat Vladimir Sementsov-Ogievskiy geschrieben: > 30.09.2019 19:00, Kevin Wolf wrote: > > Am 30.09.2019 um 17:19 hat Vladimir Sementsov-Ogievskiy geschrieben: > >> 30.09.2019 18:12, Kevin Wolf wrote: > >>> Am 24.09.2019 um 22:08 hat Vladimir Sementsov-Ogievskiy geschrieben: > >>>> Here is introduced ERRP_FUNCTION_BEGIN macro, to be used at start of > >>>> functions with errp parameter. > >>> > >>> A bit of bike shedding, but FOO_BEGIN suggests to me that a FOO_END will > >>> follow. Can we find a different name, especially now that we won't use > >>> this macro in every function that uses an errp, so even the "errp > >>> function" part isn't really correct any more? > >>> > >>> How about ERRP_AUTO_PROPAGATE? > >> > >> I have an idea that with this macro we can (optionally) get the whole call > >> stack > >> of the error and print it to log, so it's good to give it more generic > >> name, not > >> limited to propagation.. > > > > Hm, what's the context for this feature? > > > > The obvious one where you want to have a stack trace is &error_abort, > > but that one crashes, so you get it automatically. If it's just a normal > > error (like a QAPI option contains an invalid value and some function > > down the call chain checks it), why would anyone want to know what the > > call chain in the QEMU code was? > > > > When I have bug from testers, call stack would be a lot more descriptive, > than just > an error message. > > We may add trace point which will print this information, so with disabled > trace point > - no extra output.
But wouldn't it make much more sense then to optionally add this functionality to any trace point? I really don't see how this is related specifically to user-visible error messages. However, even if we decide that we want to have this in Error objects, wouldn't it make much more sense to use the real C stack trace and save it from the innermost error_set() using backtrace() or compiler built-ins rather than relying on an error_propagate() chain? Kevin
