Reporting errors from system-image-dbus are not helpful to the end user

[Barry Warsaw]

We were discussing the recent rash of errors folks are seeing when trying to upgrade. While debugging these, it came up that the ui reporting FileNotFound errors or SignatureErrors is probably not very helpful to the user. There's really not much they can do other than just try again. The error messages won't be helpful to us devs either - the log files contain all the gory details we need.

So Rick suggested that we file a bug to just tell the user to "Try again later" or some such.

[Sebastien Bacher (seb128)]

Thanks for your bug report.

Matthew, do you have some idea on how we could better report backend errors to users?

[Matthew Paul Thomas (mpt)]

Are FileNotFound errors or SignatureErrors the same as any of the errors listed in bug 1215901? If so, which are they? And if not, how can I find a complete list of update error cases?

[Barry Warsaw (barry)]

On Feb 12, 2014, at 11:47 AM, Matthew Paul Thomas wrote:

>Are FileNotFound errors or SignatureErrors the same as any of the errors
>listed in bug 1215901? If so, which are they? And if not, how can I find
>a complete list of update error cases?

Not really. The two above are internal system-image exceptions that get
turned into error messages for UpdateFailed signals. It seemed useful to
return the full traceback in the last_error field, but perhaps it's not.

One of the changes I'm planning on making for s-i 2.1 (coming soon) is to
provide a little better error message for the case folks are seeing in LP:
#1277589 (even though I think 2.1 will eliminate the error). Instead of the
current SignatureError details, I think saying something like "keyring chain
could not be validated" is a little more accurate.

Due to the stack of bugs exposed by the recent ui change, what's really
happening is that the downloaded keyring files are corrupt. si will move up
the chain of keyring trying to download a valid one, but once it hits the
preloaded archive-master, there are no more keyrings to download. I.e. "we've
reached the end of the chain and there's nothing more we can do".

I didn't expect the UpdateFailed error messages to be user consumable, but if
they are going to be displayed to the end user, let's come up with a good set
of texts.

There's no fantastic way of telling what all the error cases will be, although
FileNotFoundError, SignatureError, KeyringErrors, and ChecksumError is
probably a pretty good start.