CompactionCoverage
What the compaction phases actually reached, accumulated across one harness's run calls — the rig receipt for CompactableLatticeLawSuite.compactionIsReachedAndBigEnoughToDiscriminate.
A compaction phase that never compacts is green, and so is one that only ever drops a single id. Both are indistinguishable from a working phase by every assertion the phase makes, which is exactly how #2019 arrived: the convergence suites were green on all three canonicalisation mechanisms reverted, because they never called compact() at all. So the phases count what they reached and the suite asserts floors on the counts.
Parameters
LatticeLawHarness.run calls made with a compactor bound.
runs in which the post-merge phase performed at least one state-changing compaction. Guards V1 — "the hook never fires".
the largest single compaction step seen, in ids. Guards V2 — "it fires, but too small to discriminate": a Compact carrying one id has exactly one key order and a one-element dropped-dot set has exactly one element order, so no ordering defect is detectable at size 1. This is the metric that a floor phrased as "compaction happened" misses.
runs in which two or more replicas each compacted alone before the merge. One is not enough: the pre-merge phase exists to vary the merge of already-compacted states, and with a single compacted operand there is nothing to merge it with. This is the count that pins MovableTree.compactedDots, which the post-merge phase cannot see at all (see LatticeLawHarness.run).