Reuse exact baseline analysis results

Cache the default branch’s analysis result by revision, so each PR analyzes only its own side.

Prompt

Evaluate and apply this CI technique to my repository: Reuse exact baseline analysis results.

Cache the default branch’s analysis result by revision, so each PR analyzes only its own side.

Read the technique and its source-backed company examples: https://starsling.dev/ci-playbooks/techniques/cache-baseline-results.md

Inspect this repository’s CI workflows, build and test commands, dependencies, and recent run timings. Identify where this technique applies and explain the expected benefit using this repository’s evidence.
Measure a baseline from recent comparable runs: elapsed time, queue time, runner minutes and failures where available. If data is unavailable, say what cannot be measured.
Compare relevant company approaches, checking prerequisites, platform differences and tradeoffs. Rank applicable options by evidence, fit and measurable opportunity; do not present company results as predictions for this repo.
Recommend the smallest safe change, show what checks and fallback paths remain, and ASK ME WHICH CHANGE TO APPROVE BEFORE EDITING ANY FILES.
Only after approval, work on a new feature branch, make one reversible change, and open a reviewable pull request. Never merge or push to a default or protected branch.
Keep required checks, test coverage, deployment and release behavior intact. Validate the change and compare equivalent runs where possible; report limitations and what should be monitored after merge.

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How Stripe used this technique

Read what Stripe changed and follow the original sources.

Reuse exact baseline analysis results

Stripe iOS caches generated public interfaces and dead-code findings keyed by exact revision, toolchain and build recipe, and size checks cache baseline measurements by commit and toolchain. Invalid or absent entries rebuild, and the PR’s own revision is always analyzed.

With a cached baseline, the API check went from about 14 to about 4 minutes; without one, about 9 minutes, with the related build-scope changes. Source

Use it when: Every PR rebuilds the same default-branch baseline before comparing its changes.
Before applying it: Key the cache on every semantic input, validate the artifact before use, and keep untrusted writers away from trusted consumers. A corrupt or absent entry rebuilds the baseline.

How Stripe used this technique

Reuse exact baseline analysis results

Related techniques

Build before starting the emulator

Install a pinned tool release

Release query results before they become a timeout

Company Playbooks