Pin Metric Revisions Before Repository Usage Backfills Rewrite History

Primary source: https://github.blog/changelog/2026-07-17-github-copilot-app-now-available-in-the-usage-metrics-api/. GitHub added Copilot app activity to the usage metrics API on July 17. When a source or product surface enters a metric, historical totals may arrive late or change meaning. A dashboard that overwrites rows cannot explain yesterday's number. metric key = repository + day + surface + definition_version observation = value + fetched_at + source_revision Enter fullscreen mode Exit fullscreen mode Store append-only observations, then materialize the latest accepted revision. Test these sequences: Sequence Invariant same page fetched twice no duplicate logical row late app data arrives revision increases repository renamed stable ID preserves series definition changes old and new versions not merged backfill races daily job deterministic winner A small simulator should permute ingestion order and assert that the materialized view converges for the same observation set. Keep provenance so reports can be reproduced as-of a prior timestamp. This pattern does not claim GitHub will revise historical data; it prepares for late, duplicated, or definition-changing telemetry common to usage systems. Does your metrics store preserve what the dashboard knew yesterday?