chore(CI): cache coverage baseline from main for regression checks#4875
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abdnh
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## Linked issue Closes #4874 ## Summary / motivation Adds `tools/coverage/check-coverage-regression.py` to compare line coverage percentages from the current PR against the baseline saved from main (introduced in #4875). If any stack regresses beyond the configured tolerance (0.10%), the CI fails with a clear message showing the delta. Stacks checked: Rust, python-pylib, python-qt, TypeScript. ## How to test Try to add some new code without any tests. The Ci must fail. ## Before / after behavior Before: no signal when a PR reduces coverage below the current main level. After: CI fails on `Check coverage regression` with output like: ``` [rust] REGRESSION: 62.64% -> 61.00% (delta: -1.64%, tolerance: 0.10%) 1 stack(s) with coverage regression: rust ```
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Linked issue
Refs #4874
Summary / motivation
Stores the coverage results from every push to
mainin a GitHub Actionscache (
coverage-baseline-linux-{sha}). This is the foundation for afollow-up PR that will compare PR coverage against this baseline and fail
if any stack regresses.
No behavior change for PRs yet — the baseline is only saved, not used.
Before / after behavior
Before: no coverage data persisted between CI runs.
After: each push to
mainsavesout/coverage/as a cache entry, keyedby commit SHA, retrievable by prefix
coverage-baseline-linux-.