[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

[mpivchev]

1. 412 on MOVE/COPY: Fixed for chunked upload.
2. https://www.rfc-editor.org/info/rfc4918/#section-9.3.1 says 405 (Method Not Allowed) - MKCOL can only be executed on an unmapped URL. meaning a file already exists in that path. The error message is correct.
3. New string is "The file or folder has changed on the server. Please refresh and try again." Keep in mind the iOS app PR has more specific messages.

[mpivchev]

Some errorDescription strings were already changed. Will fix the rest.

[mpivchev]

Added new messages for remaining errorDescriptions

[SystemKeeper]

Nice work!
Please squash the commits and use a meaningful commit message.

[marinofaggiana]

The PR looks much better now, and I think the overall architecture is solid.

I have a few remaining considerations:

1. 409 Conflict: The message "The file or folder has changed on the server" is still potentially misleading. A 409 can also occur when a parent directory does not exist or due to other WebDAV conflicts. I would prefer a more neutral message, such as "The operation could not be completed because of a conflict on the server." The iOS client can provide more specific messages when the operation context is known.

2. 401 Unauthorized: "Your login is no longer valid. Please log in again." may not always be accurate, especially during an initial login attempt with incorrect credentials. A more neutral generic message would be safer.

The changes to 412 and 405 look reasonable to me now, and the additional tests are a good improvement.

Overall, I'm happy with the direction. Once these remaining points are addressed or verified, I think the PR is ready for approval.