Coverage gate

The workspace ships a tiered, blocking coverage gate. Core components must reach 95% line and function coverage; supporting and tool crates must reach 75%. The gate is enforced by scripts/coverage_gate.sh; CI runs it as part of scripts/check.sh (without || true, so it can fail the build).

The tiers are:

• Core (95%): the engine proto / cluster / io / hashkit / crypto / msg / core / net layers and the dyniak datastore / proto / datatypes / mapreduce layers -- the code a customer's data integrity depends on.
• Supporting (75%): the remaining library crates (dynomite-search, gen-fsm, dyn-sup, dyn-encoding, dynomite-text, dynomite-vec, dyn-hashtree, throttle-core).
• Tool (75%): dyniak-bench, dyn-hash-tool, dyn-admin, and the test-harness crates loom-tests / model-tests.

Running locally

scripts/coverage_gate.sh             # enforce the tiered policy
scripts/coverage_gate.sh --report    # report-only; do not fail

The script writes:

• target/coverage/summary.json - the raw cargo-llvm-cov summary (--json --summary-only).
• target/coverage/report.txt - human-readable percentages, documented deviations (warnings only), and undocumented per-file deviations (errors).

How the gate decides

1. The script invokes:

   cargo llvm-cov --workspace --features riak --summary-only --json \
       --output-path target/coverage/summary.json
   

2. It walks every per-file source entry under crates/ (skipping tests/, benches/, and the fuzz crate), assigns each file its tier threshold, and compares the file's line and function coverage to that threshold.

3. A file below its tier is classified as either:

   • Documented deviation: listed in docs/coverage-deviations.md. The gate logs a warning but does not fail.
   • Undocumented deviation: any file under its tier that is not in the deviations list. The gate fails.

4. The workspace-wide line, region, and function percentages are printed for trend tracking but are not themselves gated; the per-file tier policy is the enforcement axis.

Tracking deviations

docs/coverage-deviations.md lists each module allowed below its tier along with its line / region / function percentages and a concrete reason. Every entry is reachable only by an out-of-process suite (the conformance harness or the chaos rig), is a re-export facade, is process bootstrap, is rendering output, or has only unreachable defensive arms left -- none is an untested unit of pure logic. Regenerate the table with:

scripts/coverage_gate.sh --report
python3 scripts/regen_coverage_deviations.py

When you reduce a deviation:

1. Add tests that lift the module to its tier threshold.
2. Run scripts/coverage_gate.sh --report and regenerate the deviations table; the file drops out automatically.

Soak coverage

The soak job runs property tests at 1M cases each (make soak) and re-runs scripts/coverage_gate.sh with the same tiered thresholds. The expectation is that soak coverage matches or exceeds the per-PR coverage; any regression is a soak finding that blocks the next release tag.