[BUG] Fork log should error on incomplete manifest

[Sicheng-Pan]

Description of changes

Summarize the changes made by this PR.

• Improvements & Bug fixes
  • Throw error during fork_log if the first available offset in the copied manifest is ahead of the compaction cursor
• New functionality
  • N/A

Test plan

How are these changes tested?

• Tests pass locally with pytest for python, yarn test for js, cargo test for rust

Migration plan

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Observability plan

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Documentation Changes

Are all docstrings for user-facing APIs updated if required? Do we need to make documentation changes in the _docs section?_

[Sicheng-Pan]

• [BUG] Fork log should error on incomplete manifest #5771 👈 (View in Graphite)
• main

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[github-actions]

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Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
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• Are error messages user-friendly?
• Have all documentation changes needed been made?
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Quality

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[propel-code-bot]

Add sanity checks in fork_logs to detect incomplete copied manifest

Small patch in the Rust log-service that hardens the fork_logs flow. After copying a source log to the target collection via wal3::copy, the code now loads the copied manifest directly and validates two invariants:

1. The compaction cursor (offset) must not be behind the first timestamp recorded in the copied manifest (first_copied_offset).
2. The compaction cursor must be ≤ the manifest’s next_write_timestamp (existing check, now performed against the in-memory manifest rather than an extra reader call).
   If either invariant fails, the RPC returns Status::internal instead of silently proceeding, preventing reads or writes on an inconsistent fork.

Key Changes

• Added new_manifest retrieval via log_reader.manifest().await inside fork_logs
• Introduced check if offset < first_copied_offset { return Err(Status::internal(...)) }
• Replaced previous log_reader.next_write_timestamp().await call with new_manifest.next_write_timestamp()
• Updated variable names (first_copied_offset, max_offset) and error text to clarify failure cases

Affected Areas

• rust/log-service/src/lib.rs – function LogServer::fork_logs

This summary was automatically generated by @propel-code-bot