Errors during smooth updates not displayed

[mordauk]

When a smooth update (introduced in #29820) fails to complete, an error is supposed to be displayed. This, however, does not appear to be the case anymore. Update errors fail to display in trunk and also 4.3.1. It could be be happening in other versions as well but I have not confirmed it.

Instead of displaying a visual error, the updating indicator just spins forever.

I have confirmed this on a local test site and also on a live site running 4.3.1.

This can be easily tested by forcibly returning a WP_Error at the top of download_package() in WP_Upgrader.

[mordauk]

It appears to be failing because the WP_Error is never passed back to wp.updates.updateError in updates.js. It ges a 0 response instead.

[dd32]

This is caused by #27365

[dd32]

In 35371:

Updates: Add a generic failure case to the ajax update endpoint for when the WP_Error value hasn't been found.

See #34403

[dd32]

It's also hard to explain, but most errors are handled, it's just the "lower level" ones which are not filesystem related (connection/cannot write/cannot create folder/etc) which are missed.

#27365 is going to be required to have a non-generic error message, [35371] simply displays Update Failed: Plugin update failed. when it hits an error condition.
[35371] could be backported to 4.3, but as 4.4 is in beta I think that's not really worth it.

[mordauk]

Was this indirectly fixed in another patch?

[ocean90]

Replying to mordauk:

Was this indirectly fixed in another patch?

See [35371].

[mordauk]

That doesn't actually catch the errors originally described in this ticket. It doesn't catch WP_Error instances returned with failed downloads, at least not the last time I tested it after https://core.trac.wordpress.org/changeset/35371 was committed.