Re: Error handling in apt-install
Frans Pop <elendil@planet.nl> writes:
<...>
>> Currently apt-install usage differs from this concept and I'm aware of
>> it; is this what is more logical to enduser?
>>
>> I think that different installation methods shouldn't have different
>> final results and this looks logical to me. For this to be done, the
>> only way I see is if all apt-install calls are "required to be
>> satisfied".
<...>
> In Debian in general we have several classes of packages: essential,
> standard, optional, etc. I hope you'll agree that distinction is useful.
>
> IMO during installation we have the same: some packages are more required
> than others. Anything apt-install'ed that's needed to successfully reboot
> the installed system in 100% required and failure to install them should
> result in errors.
>
>> What use cases do you see that apt-install calls should be used as
>> "non-required" action?
>
> I think that for example a failure to apt-install installation-reports
> should not result in an error being displayed, and certainly not in the
> installation as a whole being failed. The same goes for acpi and (IMO
> though I know you don't agree) laptop-detect.
>
> Or are you saying that you think apt-install should not be used to install
> such packages? That seems dumb to me as it would mean we'd need a
> different, but almost identical script, to handle those other packages.
> Seems better to me to make apt-install flexible enough to handle both.
While I agree that acpi or laptop-detect aren't "fatal" for the user,
I also think that it makes much more difficult to be sure about the
final result.
Obviously I'm not suggesting to write another "almost identical"
script and all possibilities should be supported by apt-install.
I disagree about not display an error in installation-reports, acpi,
laptop-detect cases. I'd agree to offer the option to the user to
continue the installation since it's not a package that will break the
installed system but I'd like to know that a suppose to be
available/working package failed.
> There are some restrictions in the implementation too here. IMO we don't
> want 31 levels of "requiredness", each with its own error message (if only
> because of translations overhead).
> My current implementation allows for only one error message in apt-install
> itself: the installation of package(s) <packages> failed; this may affect
> the correct functioning of the installed system.
> I hope you'll agree that that message is not suitable if installation of
> installation-reports fails.
I agree that this message isn't suitable for the example case.
> My implementation also supports the following cases:
> - package is not essential, so errors can be ignored
> - package is queued and installed during base-install; apt-install should
> do the error handling
> - package may be queued or installed directly and apt-install should do
> the error handling
> - package will always be installed directly and error handling is done
> by calling script
>
> I hope that I've now made _my_ arguments totally clear.
> Back to you (and others of course).
This flexibility looks nice and I'm not opposed to provide it. This
can be even more useful for CDDs and derivatives.
I'd suggest the following cases to be supported:
- package optional, so errors can be ignored (not to be used by d-i)
- package is not essential, apt-install reports error but lets user
to continue
- package is queued and installed during base-install; apt-install should
do the error handling
- package may be queued or installed directly and apt-install should do
the error handling
- package will always be installed directly and error handling is done
by calling script
This way the user knows something went wrong but is able to
continue. We offer flexibility to derivatives and CDDs if they like to
have it but avoid the case of something not being available and user
to not be notified (in official installer).
This is now a useful discussion :-)
Please, comment about my points if possible.
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