[BUG]: Fix offset flushed to output collection after fn invocation

[tanujnay112]

Description of changes

Summarize the changes made by this PR.

We were flushing the input collection's pulled offset to the output collection's compacted offset field during function invocation. This change fixes that.

• Improvements & Bug fixes
  • ^^^
• New functionality
  • ...

Test plan

How are these changes tested?

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

Migration plan

Are there any migrations, or any forwards/backwards compatibility changes needed in order to make sure this change deploys reliably?

Observability plan

What is the plan to instrument and monitor this change?

Documentation Changes

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

[tanujnay112]

• [BUG]: Fix offset flushed to output collection after fn invocation #5770 👈 (View in Graphite)
• main

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[github-actions]

Reviewer Checklist

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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?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[propel-code-bot]

Separate input vs output log offsets during compaction registration

Introduces distinct tracking for the pulled log offset of the input collection versus the output collection during compaction/attached-function execution. The change corrects a bug where the input offset was incorrectly flushed as the output collection’s compacted offset, leading to wrong completion_offset calculations for attached functions.

Key Changes

• Replaced pulled_log_offset with input_pulled_log_offset and new output_pulled_log_offset in CompactOrchestrator (rust/worker/src/execution/orchestration/compact.rs).
• Added helper method set_input_log_offset() to synchronise offsets only when input and output collections are identical.
• Propagated new fields through constructor, state initialisation, fetch-log handling, and register flow.
• Extended RegisterInput with input_pulled_log_offset and updated completion_offset computation to use it, avoiding prior off-by-one bug.
• Adjusted all call sites (compactor path & unit tests) to pass the additional parameter.

Affected Areas

• rust/worker/src/execution/orchestration/compact.rs – state struct, fetch-log handling, register logic
• rust/worker/src/execution/operators/register.rs – input struct, offset calculation, tests

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

[rescrv]

why .max(0) if you're guaranteeing it's greater than zero?

[tanujnay112]

Good catch, thanks!