ref(data-export): Extract helper methods from endpoint and assemble_download task

[manessaraj]

Break down the monolithic post() handler and assemble_download
task into focused private helpers to enable further refactoring
for new export functionality. Also introduce an AssembleChunkResult
NamedTuple and a Processor type alias to reduce repetition. No behavior change.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Unused run_sync parameter never read or propagated

Low Severity

The new run_sync parameter on assemble_download is never read within the function body and no caller passes it. Additionally, neither _schedule_retry nor _schedule_next_task propagates it when scheduling continuation tasks via apply_async, so even if a future caller sets run_sync=True, subsequent retries and continuations would silently revert to the default False. This is dead code that could mask a latent bug once the parameter is eventually wired up.

Additional Locations (2)

• src/sentry/data_export/tasks.py#L210-L223
• src/sentry/data_export/tasks.py#L268-L273

 

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