`check` treated any difference between stored and recomputed metrics as
a gate failure, so a model written by an older brick (without the
`metrics.resolution` field, or with an older formula) always failed,
even with every threshold met. CI checking an archived or cached model
broke on upgrade.
The gate already uses recomputed metrics, so a mismatch is now a
stderr warning. Only fields present in both copies are compared, so a
missing newer field does not count as a mismatch. Tampered metrics
still cannot pass: the existing test's recomputed cycle count fails the
gate, and it still reports "stored metrics".
Test: a freshly built model with `metrics.resolution` removed passes
`check --min-score 0`; it failed before this change.
A directory with no supported source (Go/Java only) built
"1 nodes / 0 edges; score 100.0" with no diagnostic, and
`check --min-score 90 --max-cycles 0` passed it. The one-line summary
also hid diagnostics entirely: the yams run's 7,428 warnings (505 files
with grammar errors) never appeared.
- scan records a warning diagnostic when no source file was scanned;
- `build` prints the diagnostic and warning counts in its summary and
warns on stderr when the model is empty;
- `check` fails a model that contains no scanned source files.
Test: diff_cli::a_scan_with_no_supported_source_is_reported_and_fails_check
fails before this change (no diagnostic; check passes).
`brick check` read `metrics` from the model JSON and gated on them, so
setting `cycle_count` to 0 and `score` to 100 in the file turned a
failing `--max-cycles 0` gate into "passed" without changing the graph.
check now recomputes the metrics from the loaded nodes and edges and
gates on those; if the stored copy differs, that is itself a failure
("stored metrics do not match the graph"). Honest models recompute to
identical values, so existing gates are unchanged.
Test: diff_cli::check_recomputes_metrics_instead_of_trusting_the_file
fails before this change (the tampered model passes).
