Snap delta too large warning language can be improved

[Mark Shuttleworth]

Saw this today:

  Error generating delta: delta generated was too large.
  Falling back to pushing full snap...

Can we change this to a single line, please:

  Large delta, pushing full snap.

If we have a simple definition of large, then let's be explicit, for example:

  Delta saving is less than 20%, pushing full snap.

[Kyle Fazzari (kyrofa)]

https://github.com/snapcore/snapcraft/pull/1345

[Mark Shuttleworth (sabdfl)]

Thank you both :)

[Leo Arias (elopio)]

Wait wait, with Gustavo we only made one change to send the percentage from the backend to the UI. The text is still not what Mark suggested. It currently says:

Error generating delta: delta saving is less than 10%.
Falling back to pushing full snap...

I'm bringing this back to confirmed, and adding the tag to get somebody from the design team to take a look at our delta error messages because we didn't review them during the sprint.

[Carla Berkers (carlaberkers)]

Hi Leo, as far as I can tell your proposal looks sensible.

Do you use a convention for how to phrase error messages?

[Kyle Fazzari (kyrofa)]

Whoops, sorry guys, looks like I jumped the gun there. Let's please be clear in the PR if the buglink isn't completely fixed by it.

[Leo Arias (elopio)]

@Carla, sorry for the late response.

We try to make errors consistent. One time I collected all the error messages and we looked at them, making a few changes to make them nicer. It might be time to do it again, to make sure that the new ones are being consistent too.

I'm marking this as triaged, so we can rephrase the message.

[Gustavo Silva (gsilvapt)]

@elopio how are things on this design request? Perhaps we could work on this one some time soon?