[mpivchev]

Removes technical server error strings with more appropriate (and generic) user readable strings. NKLog still prints the proper server errors.

Ex: 507: Storage quota is reached becomes There is not enough storage space left on the server. etc.

What changes

• NKError.kind: Classifies between URL errors, HTTP statuses, OCS codes and the WebDAV InvalidPath exception.
• NKError.localizedGenericMessage: one translated message per kind. Only exception is unified sharing API, which prints user friendly messages from server.

Related: nextcloud/ios#4397 (TLDR: also adds contexts to degeneralize kind errors, ex: Could not delete Report.pdf and is iOS Files specific)
Blocked by: nextcloud/docker-ci#1011

[marinofaggiana]

The overall approach looks good, and separating technical error descriptions from user-facing messages is a welcome improvement.

However, I have a couple of concerns about the HTTP status classification:

• 412 on MOVE/COPY: A precondition failure does not necessarily mean that the destination already exists. It may also be caused by other failed HTTP preconditions, such as ETag validation.
• 405 on MKCOL: While this commonly indicates an existing resource in WebDAV, it should not automatically be interpreted as a name conflict in every situation.
• 409 Conflict: The generic message suggesting that the item was changed on the server may be misleading for conflicts caused by other conditions.

I would also recommend checking existing Nextcloud iOS consumers of errorDescription, since it is no longer guaranteed to contain a localized user-facing message.

I think the architecture is sound, but these classifications should be refined before merging.

[marinofaggiana]

read consideration