pCloud currently depends on unreleased OpenDAL fixes (apache/opendal#7617)

[mro68]

Summary

pCloud is already enabled in rustic's backend stack, but it is not fully reliable with the currently released OpenDAL state.

From practical usage, pCloud operations still fail in scenarios that are addressed by the still-open OpenDAL PR below.

OpenDAL dependency PR (currently open): apache/opendal#7617

Why this matters

rustic users can select/use pCloud now, but behavior can still be inconsistent or failing until the OpenDAL fixes are merged and released.

This creates a mismatch between "feature appears enabled" and "feature works reliably in production".

Upstream context

• pCloud is enabled in rustic_core backend OpenDAL feature set:
  • https://github.com/rustic-rs/rustic_core/blob/main/crates/backend/Cargo.toml
• OpenDAL PR #7617 adds pCloud fixes relevant for real-world rustic workloads:
  • digest auth compatibility
  • recursive listing improvements
  • read-path caching/performance fixes

Observed impact (user-facing)

Typical repository operations against pCloud can fail or behave unreliably before OpenDAL PR #7617 is included in a released OpenDAL version.

Expected behavior

If pCloud is presented as available, core operations should work reliably with released dependencies.

Proposal

1. Track this as a dependency blocker for pCloud stability.
2. Once OpenDAL releases a version containing #7617, bump dependency in rustic_core/rustic.
3. Add/confirm regression coverage for pCloud workflows before considering it stable.
4. Optionally mark pCloud as experimental/limited until that dependency is available in a release.

Environment

• OS: Linux
• Repository: rustic-rs/rustic
• Backend: pCloud via OpenDAL

Thanks for taking a look.

[mro68]

Clarification: this is not Linux-only.

I have now also tested on Windows, and the same pCloud reliability problems are reproducible there as well.
So this should be treated as a cross-platform issue (at least Linux + Windows), likely tied to shared backend behavior rather than OS-specific behavior.