feat: re-enable WebDAV pagination for large folder enumeration on macOS

[Copilot]

Description

Pagination for WebDAV PROPFIND requests was disabled due to a server-side bug that caused incorrect results. This led to timeouts and memory exhaustion when enumerating folders with 1000+ files, as all items were fetched in a single request.

The server bug was fixed and backported to Nextcloud 31+. This change re-enables pagination with version gating to ensure compatibility.

Changes

Core Implementation (Enumerator.swift, 30 lines)

• Check server capabilities to determine version (uses existing 30-min cache)
• Enable pagination (pageSettings) only for serverVersion >= 31
• Parse and forward pageIndex and pagination token from NSFileProviderPage
• Remove unconditional nextPage = nil that disabled pagination
• Older servers automatically fall back to non-paginated requests

Tests (EnumeratorTests.swift, 226 lines)

• Verify pagination enabled for NC31+ servers
• Verify graceful fallback for NC30 and older
• Test multi-page enumeration with 50+ items

Technical Details

The implementation leverages existing pagination infrastructure:

• EnumeratorPageResponse parses x-nc-paginate* headers from server
• readServerUrl handles paginated requests when pageSettings != nil
• Capabilities fetching is cached, no performance impact

Before:

let readResult = await Self.readServerUrl(
    serverUrl,
    pageSettings: nil,  // Always disabled
    // ...
)
// ...
nextPage = nil  // Force disable even if server provided next page

After:

let supportsPagination = (capabilities?.version.major ?? 0) >= 31
let pageSettings = supportsPagination ? (page: parsedPage, index: pageIndex, size: pageItemCount) : nil

let readResult = await Self.readServerUrl(
    serverUrl,
    pageSettings: pageSettings,  // Conditionally enabled
    // ...
)
// nextPage respects server response for NC31+

Scope

Changes are isolated to macOS File Provider (NextcloudFileProviderKit). Desktop sync client C++ code (LsColJob) does not currently support pagination and is out of scope.

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Signed-off-by: GitHub Copilot noreply@github.com

Original prompt

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This section details on the original issue you should resolve

<issue_title>Reenable Paginated WebDAV Requests</issue_title>
<issue_description>## Problem

When the desktop client requests the content listing of a directory with many items (like a few thousand or more), the request may fail both server or client side due to time outs or memory limits because the response always

Solution

Leverage paginated requests again. This was already implemented in the past but disabled to due to a regression in the server code.

Pitfalls

The server-side pagination was fixed but the fix is only available with Nextcloud 31 or newer. It must be assumed that older server releases do not support paginated responses. This must be taken into account in the implementation to gracefully still give clients connected to outdated server releases a chance.

History

• This is a replacement for Re-enable pagination nextcloudfileproviderkit#109
• We had to disable paginated requests: Disable pagination nextcloudfileproviderkit#108
• Due to this server bug: [Bug]: DAV missing collection type in paginated PROPFIND requests server#53674
• Which was fixed with this pull request: fix(pagination): render multistatus to XML before caching server#56035
• Which was back ported to stable Nextcloud 31 and 32
• There already is a stale community pull request: fix(FileProvider): enable pagination for large folder enumeration #9286</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Reenable Paginated WebDAV Requests #9440

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[i2h3]

This currently does not build yet and is blocked due to lack of server version exposure through NextcloudCapabilitiesKit which already is in the making:

nextcloud/NextcloudCapabilitiesKit#5