Path coverage: every branch from acquisition to the first grade callback

Audited the corridor rather than trusting the recorder. Nine upstream operations
sit between acquisition success and gradeAndCacheSlate — game binding, per-date
schedule fetch, roster index, attachEventIdentity, book-price capture, team-stat
refresh, hits-factor context, matchup keys — each with its own catch. NONE of
them early-returns, so the corridor always reaches the grader; but seven of them
were SILENT, and two could be misattributed.

COVERAGE WAS INCOMPLETE. Closed:
  * BINDING — bound / unresolved / already-had, and its throw
  * SCHEDULE — dates requested, game count, and its throw. A schedule outage
    previously surfaced as an EVENT IDENTITY error because it lands in that
    catch; it now records SCHEDULE_STAGE_ERROR and rethrows unchanged.
  * ROSTER — indexed players/teams/failed and evidence-date-validity, and its
    throw. Its catch only console.warn'd, so this stage was entirely invisible.
  * DEDUPE per-reason accounting off the filter's OWN branches: invalid fields /
    non-model book / duplicate identity / capped / not examined, plus
    model-book eligibility. Counts reconcile to the input exactly.
  * GRADE BOUNDARY — `reached` is derived from a candidate count and proves
    nothing. GRADE_LOOP_ENTERED, FIRST_GRADEBESTSIDE_STARTED and
    FIRST_ONGRADED_OBSERVED are now separate control-flow facts. No model
    output is recorded; a test greps for p_win/grade/confidence/edge/side.

Terminal states now name the stage: SCHEDULE_STAGE_ERROR, ROSTER_STAGE_ERROR,
BINDING_STAGE_ERROR, EVENT_IDENTITY_STAGE_ERROR, ADMISSION_STAGE_ERROR,
DEDUPE_STAGE_ERROR, IDENTITY_ALL_UNRESOLVED, ALL_REJECTED,
DEDUPE_ALL_NON_MODEL_BOOK, DEDUPE_ALL_INVALID_FIELDS, DEDUPE_EMPTY_OTHER,
READY_FOR_GRADING, GRADE_LOOP_STARTED, FIRST_GRADE_CALLBACK_OBSERVED.

TRACE COMPLETENESS INVARIANT. `reconcilePregrade` — acquisition NONZERO +
CONTINUED with no correlated downstream state is an OBSERVABILITY_GAP, never a
pipeline verdict. This programme has twice read an absence as a conclusion
("MLB exited at acquisition", "all props rejected at admission"); both were
wrong. Now it is a typed state with tests.

dedupeProps takes an OPTIONAL stats object and increments on the branches it
already takes, in the same order — reused, never reimplemented. Without the
object it is byte-identical; a test asserts that.

A PRODUCTION-BREAKING BUG CAUGHT BY THE FULL SUITE: the frozen no-op recorder
did not implement gradeStarted/firstOnGraded, so any caller without a recorder
threw inside the grade loop — and gradeAndCacheSlate's catch turned that into
{written:false,count:0}. Every slate would have graded NOTHING, silently. Fixed,
NO_PREGRADE now covers the full recorder surface, and a test asserts it does.

Exception semantics unchanged throughout: every added catch records and RETHROWS
the identical error. Admission rules, dedupe predicates, MODEL_BOOKS, event
identity, gameBinder, gradeBestSide and its arguments: 0 changed lines.
eventIdentity, oddsService, retentionService, gameBinder, bookRoles,
analyzeViaEngine1, probabilityEstimator, snapshotScheduler and ledgerService:
UNCHANGED. Zero new external calls — the only diff hit is the existing
getScheduleWithPitchers line re-indented into its own try.

Twelve teeth, injections verified present, against a green baseline of 89:
upstream catch silent (1) · missing trace as failure (1) · admission exception
as ALL_REJECTED (2) · non-model-book as duplicate (3) · dedupe-empty as
rejection (1) · falsely says grading started (6) · onGraded unrecorded (1) ·
sport overwrite (2) · intraday overwrite (1) · different attempt id (3) ·
observer adds an external call (1) · store failure changes outcome (2).
Restored byte-identically; teeth 3/4/6 re-run after the NO_PREGRADE fix.

The first teeth pass ran against a baseline the finer states had invalidated;
six superseded assertions were updated first and the run repeated.

388 suites / 5,269 tests pass. web tsc exit 0. Lineage stays OFF.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CQJeAG8vcDoL5zkiaJyVb8

src/services/gradeSlateService.js

@@ -58,7 +58,14 @@ const { isModelBook } = require('../config/bookRoles');
 // statsapi is free and unlimited. Concurrency stays at 5 — one variable at a time.
 //
 // Env-tunable so the ceiling can move without a deploy: GRADE_SLATE_LIMIT.
-const NO_PREGRADE = Object.freeze({ identity() {}, admission() {}, dedupe() {}, gradeLoop() {} });
+// MUST implement EVERY recorder method. A missing one throws inside the grade
+// loop, and gradeAndCacheSlate's catch turns that into {written:false,count:0}
+// — i.e. a silently empty slate for every caller without a recorder.
+const NO_PREGRADE = Object.freeze({
+  binding() {}, schedule() {}, roster() {},
+  identity() {}, admission() {}, dedupe() {}, gradeLoop() {},
+  gradeStarted() {}, firstOnGraded() {},
+});
 
 const DEFAULT_LIMIT = Number(process.env.GRADE_SLATE_LIMIT) > 0
   ? Number(process.env.GRADE_SLATE_LIMIT)
@@ -201,17 +208,31 @@ function propositionEventKey(p) {
   return `legacy:${date}:${away}@${home}`;
 }
 
-function dedupeProps(props, limit) {
+function dedupeProps(props, limit, stats) {
   const seen = new Set();
   const out = [];
-  for (const p of props || []) {
-    if (!p || !p.player || !p.stat_type || p.line == null) continue;
-    if (!isModelBook(p.book)) continue;
+  // DIAGNOSTIC COUNTERS ONLY. Incremented on the SAME branches the filter
+  // already takes, in the same order, so the counts describe the real code path
+  // rather than a second implementation of it. `stats` is optional; without it
+  // this function is byte-identical in behaviour.
+  const bump = (k) => { if (stats) stats[k] = (stats[k] || 0) + 1; };
+  const list = props || [];
+  let examined = 0;
+  for (const p of list) {
+    examined += 1;
+    if (!p || !p.player || !p.stat_type || p.line == null) { bump('dropped_invalid_fields'); continue; }
+    if (!isModelBook(p.book)) { bump('dropped_non_model_book'); continue; }
     const key = `${propositionEventKey(p)}::${p.player}::${p.stat_type}::${p.line}`;
-    if (seen.has(key)) continue;
+    if (seen.has(key)) { bump('duplicate_identity_removed'); continue; }
     seen.add(key);
     out.push(p);
-    if (out.length >= limit) break;
+    if (out.length >= limit) { if (stats) stats.capped = true; break; }
+  }
+  if (stats) {
+    stats.input_count = list.length;
+    stats.output_count = out.length;
+    stats.model_book_eligible = out.length + (stats.duplicate_identity_removed || 0);
+    stats.not_examined = list.length - examined;
   }
   return out;
 }
@@ -382,8 +403,9 @@ async function gradeAndCacheSlate(sport, props, opts = {}) {
         + `${gate.rejected.length} rejected ${JSON.stringify(gate.reasons)}`);
     }
     let unique;
+    const dedupeStats = {};
     try {
-      unique = dedupeProps(gate.admitted, limit);
+      unique = dedupeProps(gate.admitted, limit, dedupeStats);
     } catch (eDed) {
       pregrade.dedupe({ started: true, completed: false, threw: true, input_count: gate.admitted.length, error: eDed && eDed.message });
       throw eDed;
@@ -393,11 +415,24 @@ async function gradeAndCacheSlate(sport, props, opts = {}) {
       input_count: gate.admitted.length,
       output_count: unique.length,
       removed_count: gate.admitted.length - unique.length,
+      // Per-reason accounting straight off the filter's own branches.
+      dropped_invalid_fields: dedupeStats.dropped_invalid_fields || 0,
+      dropped_non_model_book: dedupeStats.dropped_non_model_book || 0,
+      duplicate_identity_removed: dedupeStats.duplicate_identity_removed || 0,
+      model_book_eligible: dedupeStats.model_book_eligible || 0,
+      non_model_book: dedupeStats.dropped_non_model_book || 0,
+      capped: !!dedupeStats.capped,
+      not_examined: dedupeStats.not_examined || 0,
     });
     pregrade.gradeLoop({ candidate_count: unique.length, reached: unique.length > 0 });
     if (unique.length === 0) return { written: false, count: 0 };
 
-    const graded = (await mapLimit(unique, concurrency, (p) => gradeBestSide(grade, p, sport, opts)))
+    const graded = (await mapLimit(unique, concurrency, (p) => {
+      // Proof that the loop actually began. `reached` above is derived from a
+      // count and cannot show this.
+      pregrade.gradeStarted();
+      return gradeBestSide(grade, p, sport, opts);
+    }))
       .filter(Boolean)
       .sort((a, b) => (Number(b.confidence) || 0) - (Number(a.confidence) || 0));
 

src/services/ops/acquisitionTrace.js

@@ -237,15 +237,29 @@ async function history(sport, deps = {}) {
 const PREGRADE_PREFIX = 'ops:pregrade:';
 
 const PREGRADE_OUTCOME = Object.freeze({
+  // Progress states — the boundary moves forward as each is proven.
   READY_FOR_GRADING: 'READY_FOR_GRADING',
+  GRADE_LOOP_STARTED: 'GRADE_LOOP_STARTED',
+  FIRST_GRADE_CALLBACK_OBSERVED: 'FIRST_GRADE_CALLBACK_OBSERVED',
+  // Refusals — the cohort was deliberately emptied, and by which filter.
+  IDENTITY_ALL_UNRESOLVED: 'IDENTITY_ALL_UNRESOLVED',
   ALL_REJECTED: 'ALL_REJECTED',
-  IDENTITY_STAGE_ERROR: 'IDENTITY_STAGE_ERROR',
+  DEDUPE_ALL_NON_MODEL_BOOK: 'DEDUPE_ALL_NON_MODEL_BOOK',
+  DEDUPE_ALL_INVALID_FIELDS: 'DEDUPE_ALL_INVALID_FIELDS',
+  DEDUPE_EMPTY_OTHER: 'DEDUPE_EMPTY_OTHER',
+  // Exceptions — each names its own stage, never folded into a refusal.
+  SCHEDULE_STAGE_ERROR: 'SCHEDULE_STAGE_ERROR',
+  ROSTER_STAGE_ERROR: 'ROSTER_STAGE_ERROR',
+  BINDING_STAGE_ERROR: 'BINDING_STAGE_ERROR',
+  EVENT_IDENTITY_STAGE_ERROR: 'EVENT_IDENTITY_STAGE_ERROR',
   ADMISSION_STAGE_ERROR: 'ADMISSION_STAGE_ERROR',
   DEDUPE_STAGE_ERROR: 'DEDUPE_STAGE_ERROR',
-  DEDUPE_EMPTY: 'DEDUPE_EMPTY',
   NO_INPUT_PROPS: 'NO_INPUT_PROPS',
   OTHER_PREGRADING_ERROR: 'OTHER_PREGRADING_ERROR',
   INCOMPLETE: 'INCOMPLETE',
+  // Reconciliation: acquisition CONTINUED but no downstream trace exists. This
+  // is an OBSERVABILITY failure, never evidence that the pipeline failed.
+  OBSERVABILITY_GAP: 'OBSERVABILITY_GAP',
 });
 
 function pregradeKey(sport) {
@@ -262,6 +276,9 @@ function beginPregrade({ attemptId, sport, trigger, codeSha, processStartedAt, p
     process_generation: processStartedAt || null,
     started_at: now || new Date().toISOString(),
     input_props_count: Number.isFinite(propsCount) ? propsCount : null,
+    binding: null,
+    schedule: null,
+    roster: null,
     identity: null,
     admission: null,
     dedupe: null,
@@ -278,10 +295,21 @@ function beginPregrade({ attemptId, sport, trigger, codeSha, processStartedAt, p
 function pregradeRecorder(trace) {
   const t = trace || {};
   return {
+    binding(info) { t.binding = { ...info, error: sanitize(info && info.error) }; },
+    schedule(info) { t.schedule = { ...info, error: sanitize(info && info.error) }; },
+    roster(info) { t.roster = { ...info, error: sanitize(info && info.error) }; },
     identity(info) { t.identity = { ...info, error: sanitize(info && info.error) }; },
     admission(info) { t.admission = { ...info, error: sanitize(info && info.error) }; },
     dedupe(info) { t.dedupe = { ...info, error: sanitize(info && info.error) }; },
-    gradeLoop(info) { t.grade_loop = { ...info }; },
+    gradeLoop(info) { t.grade_loop = { ...t.grade_loop, ...info }; },
+    // CONTROL-FLOW FACTS ONLY. `reached` is derived from a candidate count and
+    // does NOT prove grading began; these two do. No model output is recorded.
+    gradeStarted() {
+      t.grade_loop = { ...t.grade_loop, entered: true, first_gradebestside_started: true };
+    },
+    firstOnGraded() {
+      t.grade_loop = { ...t.grade_loop, first_ongraded_observed: true };
+    },
   };
 }
 
@@ -292,21 +320,66 @@ function pregradeRecorder(trace) {
  */
 function classifyPregrade(trace) {
   const t = trace || {};
-  if (t.identity && t.identity.threw) return PREGRADE_OUTCOME.IDENTITY_STAGE_ERROR;
+  const gl = t.grade_loop || {};
+  // EXCEPTIONS FIRST, each naming its own stage. An exception is never folded
+  // into a refusal, and a refusal is never reported as an exception.
+  if (t.binding && t.binding.threw) return PREGRADE_OUTCOME.BINDING_STAGE_ERROR;
+  if (t.schedule && t.schedule.threw) return PREGRADE_OUTCOME.SCHEDULE_STAGE_ERROR;
+  if (t.roster && t.roster.threw) return PREGRADE_OUTCOME.ROSTER_STAGE_ERROR;
+  if (t.identity && t.identity.threw) return PREGRADE_OUTCOME.EVENT_IDENTITY_STAGE_ERROR;
   if (t.admission && t.admission.threw) return PREGRADE_OUTCOME.ADMISSION_STAGE_ERROR;
   if (t.dedupe && t.dedupe.threw) return PREGRADE_OUTCOME.DEDUPE_STAGE_ERROR;
   if (t.input_props_count === 0) return PREGRADE_OUTCOME.NO_INPUT_PROPS;
-  if (t.grade_loop && t.grade_loop.reached) return PREGRADE_OUTCOME.READY_FOR_GRADING;
+  // PROGRESS, strongest proof first. `reached` alone is only a candidate count.
+  if (gl.first_ongraded_observed) return PREGRADE_OUTCOME.FIRST_GRADE_CALLBACK_OBSERVED;
+  if (gl.first_gradebestside_started) return PREGRADE_OUTCOME.GRADE_LOOP_STARTED;
+  if (gl.reached) return PREGRADE_OUTCOME.READY_FOR_GRADING;
+  // REFUSALS, naming the filter that emptied the cohort.
   if (t.admission && t.admission.completed && t.admission.admitted_count === 0) {
+    // Name the CAUSE when identity explains it, rather than the symptom.
+    if (t.identity && t.identity.completed && t.identity.total > 0 && t.identity.canonical === 0) {
+      return PREGRADE_OUTCOME.IDENTITY_ALL_UNRESOLVED;
+    }
     return PREGRADE_OUTCOME.ALL_REJECTED;
   }
   if (t.dedupe && t.dedupe.completed && t.dedupe.output_count === 0
       && t.admission && t.admission.admitted_count > 0) {
-    return PREGRADE_OUTCOME.DEDUPE_EMPTY;
+    const d = t.dedupe;
+    if (d.dropped_non_model_book === d.input_count) return PREGRADE_OUTCOME.DEDUPE_ALL_NON_MODEL_BOOK;
+    if (d.dropped_invalid_fields === d.input_count) return PREGRADE_OUTCOME.DEDUPE_ALL_INVALID_FIELDS;
+    return PREGRADE_OUTCOME.DEDUPE_EMPTY_OTHER;
   }
   return PREGRADE_OUTCOME.OTHER_PREGRADING_ERROR;
 }
 
+/**
+ * TRACE COMPLETENESS INVARIANT.
+ *
+ * If acquisition recorded FINAL NONZERO + CONTINUED, a downstream state must
+ * exist. Its ABSENCE is an observability failure and must never be read as
+ * "the pipeline failed" — that inference is exactly what this programme got
+ * wrong twice.
+ */
+function reconcilePregrade(acqTrace, pgTrace) {
+  const a = acqTrace || null;
+  const continued = !!(a && a.final === FINAL.NONZERO && a.outcome === OUTCOME.CONTINUED);
+  if (!continued) return { applicable: false, complete: null, outcome: null };
+  if (!pgTrace) {
+    return { applicable: true, complete: false, outcome: PREGRADE_OUTCOME.OBSERVABILITY_GAP };
+  }
+  if (pgTrace.snapshot_attempt_id !== a.snapshot_attempt_id) {
+    return { applicable: true, complete: false, outcome: PREGRADE_OUTCOME.OBSERVABILITY_GAP, reason: 'attempt_id_mismatch' };
+  }
+  const undecided = !pgTrace.outcome
+    || pgTrace.outcome === PREGRADE_OUTCOME.INCOMPLETE
+    || pgTrace.outcome === PREGRADE_OUTCOME.OTHER_PREGRADING_ERROR;
+  return {
+    applicable: true,
+    complete: !undecided,
+    outcome: undecided ? PREGRADE_OUTCOME.OBSERVABILITY_GAP : pgTrace.outcome,
+  };
+}
+
 function finishPregrade(trace, { now } = {}) {
   const t = trace;
   t.outcome = classifyPregrade(t);
@@ -328,6 +401,7 @@ async function pregradeHistory(sport, deps = {}) {
 module.exports = {
   TRIGGER, SOURCE_OUTCOME, FINAL, OUTCOME, PREGRADE_OUTCOME,
   pregradeKey, beginPregrade, pregradeRecorder, classifyPregrade, finishPregrade,
+  reconcilePregrade,
   persistPregrade, pregradeHistory,
   HISTORY_CAP, TTL_SECONDS, KEY_PREFIX,
   key, sanitize, newAttemptId,

src/services/snapshotService.js

@@ -516,6 +516,10 @@ async function runSnapshot(sport, opts = {}) {
   try {
     const binder = deps.gameBinder || require('./gameBinder');
     const b = await binder.attachGameTimes(sp, props, { gradedAt: ts });
+    pgRec.binding({
+      started: true, completed: true, threw: false,
+      bound: b.bound, unresolved: b.unresolved, already_had: b.alreadyHad,
+    });
     console.log(`[snapshot] game binding ${sp}: ${b.bound} bound, ${b.alreadyHad} already had times, ${b.unresolved} UNRESOLVED, ${b.ambiguous} ambiguous(doubleheader)`);
 
     // CANONICAL EVENT IDENTITY (MLB). The bound game_time above is what makes
@@ -532,10 +536,19 @@ async function runSnapshot(sport, opts = {}) {
         const mlbAdapter = deps.mlbAdapter || require('./adapters/mlbStatsAdapter');
         const dates = [...new Set(props.map((p) => p && p.game_date).filter(Boolean))];
         const games = [];
-        for (const d of dates) {
-          // eslint-disable-next-line no-await-in-loop
-          const g = await mlbAdapter.getScheduleWithPitchers(d);
-          if (Array.isArray(g)) games.push(...g);
+        pgRec.schedule({ started: true, completed: false, threw: false, dates_requested: dates.length });
+        try {
+          for (const d of dates) {
+            // eslint-disable-next-line no-await-in-loop
+            const g = await mlbAdapter.getScheduleWithPitchers(d);
+            if (Array.isArray(g)) games.push(...g);
+          }
+        } catch (eSch) {
+          // Record and RETHROW: the existing identity catch below still handles
+          // it exactly as before. Without this a schedule outage was reported as
+          // an event-identity error.
+          pgRec.schedule({ started: true, completed: false, threw: true, dates_requested: dates.length, error: eSch && eSch.message });
+          throw eSch;
         }
         // PARTICIPANT EVIDENCE. The prop's own team fields cannot police this:
         // when the provider nests a player under the wrong event, those fields
@@ -545,6 +558,10 @@ async function runSnapshot(sport, opts = {}) {
         // The roster is fetched AS OF THE SLATE'S DATE, not "now". statsapi
         // honours a `date` parameter and it genuinely changes the answer, so
         // the evidence describes the moment being judged.
+        pgRec.schedule({
+          started: true, completed: true, threw: false,
+          dates_requested: dates.length, games: games.length,
+        });
         const slateDate = dates.length === 1 ? dates[0] : null;
         let playerTeams = null;
         let evidenceDateValid = false;
@@ -555,11 +572,17 @@ async function runSnapshot(sport, opts = {}) {
           });
           playerTeams = built.index;
           evidenceDateValid = evid.evidenceIsDateValid(built.stats, slateDate);
+          pgRec.roster({
+            started: true, completed: true, threw: false,
+            players: built.stats.players, teams: built.stats.teams,
+            failed: built.stats.failed || 0, evidence_date_valid: evidenceDateValid,
+          });
           console.log(`[snapshot] participant evidence ${sp}: ${built.stats.players} players`
             + ` across ${built.stats.teams} rosters as of ${slateDate || 'unscoped'}`
             + `${built.stats.failed ? `, ${built.stats.failed} unreadable` : ''}`
             + ` · date-valid=${evidenceDateValid}`);
         } catch (e3) {
+          pgRec.roster({ started: true, completed: false, threw: true, error: e3 && e3.message });
           console.warn(`[snapshot] participant evidence unavailable for ${sp}:`, e3.message);
         }
         // Without date-valid evidence a conflict can only be UNRESOLVED, never
@@ -589,6 +612,7 @@ async function runSnapshot(sport, opts = {}) {
       });
     }
   } catch (e) {
+    pgRec.binding({ started: true, completed: false, threw: true, error: e && e.message });
     console.warn(`[snapshot] game binding failed for ${sp} (rows without a real game time will be skipped):`, e.message);
   }
 
@@ -698,6 +722,9 @@ async function runSnapshot(sport, opts = {}) {
     }
   }
 
+  // Records whether the hook existed at all, so `first_ongraded_observed:false`
+  // can be told apart from "no collector was attached".
+  pgRec.gradeLoop({ ongraded_hook_attached: !!collector });
   await deps.gradeAndCacheSlate(sp, props, {
     pregrade: pgRec,
     factorContext,
@@ -710,8 +737,12 @@ async function runSnapshot(sport, opts = {}) {
     source: (odds && odds.provider) || 'odds-api',
     now: deps.now,
     cacheSet: async (_k, v) => { envelope = v; },
-    onGraded: collector ? collector.onGraded : undefined,
+    // Wrapped ONLY when a collector exists, so the downstream
+    // `typeof opts.onGraded === 'function'` branch is exactly as before. The
+    // wrapper records a control-flow fact and delegates unchanged.
+    onGraded: collector ? ((base, sides) => { pgRec.firstOnGraded(); return collector.onGraded(base, sides); }) : undefined,
     onPublished: collector ? collector.onPublished : undefined,
+
   });
   // Persist the pre-grading stage trace. Best-effort at the call site: a
   // telemetry failure must never fail a healthy slate.

tests/unit/pregradeCoverage.test.js

@@ -0,0 +1,337 @@
+'use strict';
+
+/**
+ * PATH COVERAGE — acquisition success to the first real onGraded callback.
+ *
+ * Every branch in that corridor must explain itself. Twice now this programme
+ * has read an absence as a conclusion: first "MLB exited at acquisition" (from
+ * a missing retention record), then "all props rejected at admission" (from an
+ * empty collector). Both were wrong. So the rule here is that a MISSING trace
+ * is an OBSERVABILITY_GAP, never a pipeline verdict.
+ */
+
+const fs = require('fs');
+const path = require('path');
+const acq = require('../../src/services/ops/acquisitionTrace');
+const snap = require('../../src/services/snapshotService');
+const { __internals } = require('../../src/services/gradeSlateService');
+const { MODEL_BOOKS } = require('../../src/config/bookRoles');
+const ROOT = path.resolve(__dirname, '..', '..');
+const BOOK = [...MODEL_BOOKS][0];
+
+jest.setTimeout(20000);
+
+const P = (n, over = {}) => Array.from({ length: n }, (_, i) => ({
+  player: `P${i}`, stat_type: 'hits', line: 0.5 + i, sport: 'mlb', book: BOOK,
+  home_team: 'Reds', away_team: 'Cardinals', game_date: '2026-08-28', ...over,
+}));
+
+const identityOk = (counts = {}) => ({
+  buildPlayerTeamIndex: async () => ({ index: {}, stats: { players: 12, teams: 2, failed: 0 } }),
+  evidenceIsDateValid: () => true,
+  attachEventIdentity: () => ({ total: 4, canonical: 4, unresolved: 0, unsupported: 0, impossible: 0, reasons: {}, ...counts }),
+});
+
+/** Runs the REAL runSnapshot corridor; grading is stubbed unless asked for. */
+async function corridor(over = {}) {
+  const pg = []; const a = [];
+  await snap.runSnapshot('mlb', {
+    getOdds: async () => ({ sport: 'mlb', props: P(4), provider: 'propline', source: 'cache' }),
+    gradeAndCacheSlate: async () => ({ written: false, count: 0 }),
+    gameBinder: { attachGameTimes: async () => ({ bound: 4, unresolved: 0, alreadyHad: 0 }) },
+    mlbAdapter: { getScheduleWithPitchers: async () => [{ gamePk: 1 }, { gamePk: 2 }] },
+    eventIdentity: identityOk(),
+    notify: async () => {}, sleep: async () => {}, retryDelayMs: 0,
+    now: () => '2026-08-28T14:00:00.000Z', scheduledHourUtc: 14, processStartedAt: 'proc-1',
+    retention: null,
+    ledger: { recordPipelineGrades: async () => {}, captureClosing: async () => {}, gameDateFor: () => '2026-08-28' },
+    captureBookPrices: async () => ({}), buildEspnIndex: async () => ({}),
+    refreshTeamStats: async () => ({ captured: 0 }),
+    cacheGet: async () => null, cacheSet: async () => {},
+    persistAcquisitionTrace: async (t) => a.push(t),
+    persistPregradeTrace: async (t) => pg.push(t),
+    ...over,
+  });
+  return { pg: pg[0], acq: a[0] };
+}
+
+describe('UPSTREAM MLB STAGES', () => {
+  test('SCHEDULE FETCH ERROR names the schedule stage, not identity', async () => {
+    const { pg } = await corridor({ mlbAdapter: { getScheduleWithPitchers: async () => { throw new Error('statsapi 503'); } } });
+    expect(pg.schedule.threw).toBe(true);
+    expect(pg.schedule.error).toMatch(/statsapi 503/);
+    expect(pg.outcome).toBe(acq.PREGRADE_OUTCOME.SCHEDULE_STAGE_ERROR);
+    expect(pg.outcome).not.toBe(acq.PREGRADE_OUTCOME.EVENT_IDENTITY_STAGE_ERROR);
+  });
+
+  test('SCHEDULE SUCCESS records dates requested and game count', async () => {
+    const { pg } = await corridor();
+    expect(pg.schedule.completed).toBe(true);
+    expect(pg.schedule.dates_requested).toBe(1);
+    expect(pg.schedule.games).toBe(2);
+  });
+
+  test('ROSTER INDEX ERROR is visible — its catch used to swallow silently', async () => {
+    const { pg } = await corridor({
+      eventIdentity: { ...identityOk(), buildPlayerTeamIndex: async () => { throw new Error('roster 500'); } },
+    });
+    expect(pg.roster.threw).toBe(true);
+    expect(pg.roster.error).toMatch(/roster 500/);
+    expect(pg.outcome).toBe(acq.PREGRADE_OUTCOME.ROSTER_STAGE_ERROR);
+  });
+
+  test('ROSTER SUCCESS records the indexed counts', async () => {
+    const { pg } = await corridor();
+    expect(pg.roster.completed).toBe(true);
+    expect(pg.roster.players).toBe(12);
+    expect(pg.roster.teams).toBe(2);
+    expect(pg.roster.evidence_date_valid).toBe(true);
+  });
+
+  test('BINDING ERROR names the binding stage', async () => {
+    const { pg } = await corridor({ gameBinder: { attachGameTimes: async () => { throw new Error('binder boom'); } } });
+    expect(pg.binding.threw).toBe(true);
+    expect(pg.outcome).toBe(acq.PREGRADE_OUTCOME.BINDING_STAGE_ERROR);
+  });
+
+  test('BINDING SUCCESS records bound / unresolved / already-had', async () => {
+    const { pg } = await corridor({ gameBinder: { attachGameTimes: async () => ({ bound: 3, unresolved: 1, alreadyHad: 0 }) } });
+    expect(pg.binding).toMatchObject({ completed: true, bound: 3, unresolved: 1, already_had: 0 });
+  });
+
+  test('EVENT IDENTITY ERROR is recorded and the existing fallback is preserved', async () => {
+    const { pg } = await corridor({
+      eventIdentity: { ...identityOk(), attachEventIdentity: () => { throw new Error('identity boom'); } },
+    });
+    expect(pg.identity.threw).toBe(true);
+    expect(pg.outcome).toBe(acq.PREGRADE_OUTCOME.EVENT_IDENTITY_STAGE_ERROR);
+    // The existing catch keeps the slate alive — props stay on legacy identity.
+    const src = fs.readFileSync(path.join(ROOT, 'src/services/snapshotService.js'), 'utf8');
+    expect(src).toMatch(/Identity is additive: a failure leaves props on legacy identity/);
+  });
+
+  test('IDENTITY ALL UNRESOLVED reports truthful status counts', async () => {
+    const { pg } = await corridor({
+      eventIdentity: identityOk({ total: 4, canonical: 0, unresolved: 4, impossible: 0, reasons: { no_team_match: 4 } }),
+      gradeAndCacheSlate: async (sp, props, o) => {
+        o.pregrade.admission({ started: true, completed: true, threw: false, input_count: 4, admitted_count: 0, rejected_count: 4, rejection_reason_counts: { EVENT_UNRESOLVED: 4 } });
+        return { written: false, count: 0 };
+      },
+    });
+    expect(pg.identity).toMatchObject({ completed: true, total: 4, canonical: 0, unresolved: 4 });
+    expect(pg.identity.reasons.no_team_match).toBe(4);
+    // Names the CAUSE, not just the symptom.
+    expect(pg.outcome).toBe(acq.PREGRADE_OUTCOME.IDENTITY_ALL_UNRESOLVED);
+  });
+});
+
+describe('DEDUPE IS A FILTER — exact drop accounting off its own branches', () => {
+  const d = (rows, limit = 100) => { const st = {}; const out = __internals.dedupeProps(rows, limit, st); return { out, st }; };
+
+  test('behaviour is byte-identical with and without the stats object', () => {
+    const rows = [...P(3), ...P(2, { book: 'nope' })];
+    expect(__internals.dedupeProps(rows, 100).length).toBe(d(rows).out.length);
+  });
+
+  test('ALL dropped by MODEL BOOK', () => {
+    const { out, st } = d(P(5, { book: 'not_a_model_book' }));
+    expect(out).toHaveLength(0);
+    expect(st.dropped_non_model_book).toBe(5);
+    expect(st.dropped_invalid_fields || 0).toBe(0);
+  });
+
+  test('ALL dropped by MISSING REQUIRED FIELDS', () => {
+    const { out, st } = d(P(4).map((p) => ({ ...p, player: null })));
+    expect(out).toHaveLength(0);
+    expect(st.dropped_invalid_fields).toBe(4);
+    expect(st.dropped_non_model_book || 0).toBe(0);
+  });
+
+  test('only TRUE duplicates counted as duplicates', () => {
+    const one = P(1);
+    const { out, st } = d([...one, ...one, ...one]);
+    expect(out).toHaveLength(1);
+    expect(st.duplicate_identity_removed).toBe(2);
+    expect(st.dropped_non_model_book || 0).toBe(0);
+  });
+
+  test('counts reconcile to the input exactly', () => {
+    const rows = [...P(2), ...P(2), ...P(1, { book: 'x' }), { player: null }];
+    const { out, st } = d(rows);
+    const accounted = out.length
+      + (st.dropped_invalid_fields || 0) + (st.dropped_non_model_book || 0)
+      + (st.duplicate_identity_removed || 0) + (st.not_examined || 0);
+    expect(accounted).toBe(rows.length);
+    expect(st.input_count).toBe(rows.length);
+  });
+
+  test('MODEL-book eligibility is countable for the cohort', () => {
+    const { st } = d([...P(3), ...P(2, { book: 'nope' })]);
+    expect(st.model_book_eligible).toBe(3);
+    expect(st.dropped_non_model_book).toBe(2);
+  });
+
+  test('the cap records not_examined rather than pretending it saw everything', () => {
+    const { out, st } = d(P(10), 4);
+    expect(out).toHaveLength(4);
+    expect(st.capped).toBe(true);
+    expect(st.not_examined).toBe(6);
+  });
+});
+
+describe('THE GRADING BOUNDARY', () => {
+  const realGrade = () => require('../../src/services/gradeSlateService').gradeAndCacheSlate;
+
+  test('candidates > 0 but loop NOT entered is distinct from loop entered', () => {
+    const t = acq.beginPregrade({ attemptId: 'a', sport: 'mlb', propsCount: 4 });
+    acq.pregradeRecorder(t).gradeLoop({ candidate_count: 4, reached: true });
+    expect(acq.finishPregrade(t, {}).outcome).toBe(acq.PREGRADE_OUTCOME.READY_FOR_GRADING);
+    expect(t.grade_loop.first_gradebestside_started).toBeUndefined();
+  });
+
+  test('FIRST gradeBestSide START is proven through the REAL loop', async () => {
+    const t = acq.beginPregrade({ attemptId: 'a', sport: 'mlb', propsCount: 3 });
+    await realGrade()('mlb', P(3), {
+      pregrade: acq.pregradeRecorder(t), cacheSet: async () => {}, grade: async () => null,
+    });
+    expect(t.grade_loop.entered).toBe(true);
+    expect(t.grade_loop.first_gradebestside_started).toBe(true);
+    expect(acq.finishPregrade(t, {}).outcome).toBe(acq.PREGRADE_OUTCOME.GRADE_LOOP_STARTED);
+  });
+
+  test('FIRST onGraded is proven separately from gradeBestSide starting', async () => {
+    const t = acq.beginPregrade({ attemptId: 'a', sport: 'mlb', propsCount: 3 });
+    const rec = acq.pregradeRecorder(t);
+    await realGrade()('mlb', P(3), {
+      pregrade: rec, cacheSet: async () => {}, grade: async () => null,
+      onGraded: () => { rec.firstOnGraded(); },
+    });
+    expect(t.grade_loop.first_gradebestside_started).toBe(true);
+    expect(t.grade_loop.first_ongraded_observed).toBe(true);
+    expect(acq.finishPregrade(t, {}).outcome).toBe(acq.PREGRADE_OUTCOME.FIRST_GRADE_CALLBACK_OBSERVED);
+  });
+
+  test('gradeBestSide starting WITHOUT onGraded is its own state', async () => {
+    const t = acq.beginPregrade({ attemptId: 'a', sport: 'mlb', propsCount: 3 });
+    await realGrade()('mlb', P(3), {
+      pregrade: acq.pregradeRecorder(t), cacheSet: async () => {}, grade: async () => null,
+    });
+    expect(t.grade_loop.first_gradebestside_started).toBe(true);
+    expect(t.grade_loop.first_ongraded_observed).toBeUndefined();
+    expect(acq.finishPregrade(t, {}).outcome).not.toBe(acq.PREGRADE_OUTCOME.FIRST_GRADE_CALLBACK_OBSERVED);
+  });
+
+  test('runSnapshot wraps onGraded ONLY when a collector exists', () => {
+    const src = fs.readFileSync(path.join(ROOT, 'src/services/snapshotService.js'), 'utf8');
+    expect(src).toMatch(/onGraded: collector \? \(\(base, sides\) => \{ pgRec\.firstOnGraded\(\); return collector\.onGraded\(base, sides\); \}\) : undefined/);
+    expect(src).toMatch(/ongraded_hook_attached: !!collector/);
+  });
+
+  test('no model output is recorded — control-flow facts only', () => {
+    const t = acq.beginPregrade({ attemptId: 'a', sport: 'mlb' });
+    const rec = acq.pregradeRecorder(t);
+    rec.gradeStarted(); rec.firstOnGraded();
+    const blob = JSON.stringify(t);
+    for (const forbidden of ['p_win', 'grade', 'confidence', 'projection', 'edge', 'side']) {
+      expect(blob).not.toMatch(new RegExp(`"${forbidden}"`));
+    }
+  });
+});
+
+describe('TRACE COMPLETENESS INVARIANT', () => {
+  const acqOk = { snapshot_attempt_id: 'acq_1', final: acq.FINAL.NONZERO, outcome: acq.OUTCOME.CONTINUED };
+
+  test('acquisition CONTINUED + NO downstream trace = OBSERVABILITY_GAP, not failure', () => {
+    const r = acq.reconcilePregrade(acqOk, null);
+    expect(r.applicable).toBe(true);
+    expect(r.complete).toBe(false);
+    expect(r.outcome).toBe(acq.PREGRADE_OUTCOME.OBSERVABILITY_GAP);
+  });
+
+  test('a mismatched attempt id is also a gap, never a verdict', () => {
+    const r = acq.reconcilePregrade(acqOk, { snapshot_attempt_id: 'other', outcome: acq.PREGRADE_OUTCOME.ALL_REJECTED });
+    expect(r.outcome).toBe(acq.PREGRADE_OUTCOME.OBSERVABILITY_GAP);
+    expect(r.reason).toBe('attempt_id_mismatch');
+  });
+
+  test('an undecided downstream state is a gap, not a conclusion', () => {
+    for (const o of [undefined, acq.PREGRADE_OUTCOME.INCOMPLETE, acq.PREGRADE_OUTCOME.OTHER_PREGRADING_ERROR]) {
+      const r = acq.reconcilePregrade(acqOk, { snapshot_attempt_id: 'acq_1', outcome: o });
+      expect(r.outcome).toBe(acq.PREGRADE_OUTCOME.OBSERVABILITY_GAP);
+    }
+  });
+
+  test('a decided downstream state reconciles complete', () => {
+    const r = acq.reconcilePregrade(acqOk, { snapshot_attempt_id: 'acq_1', outcome: acq.PREGRADE_OUTCOME.ALL_REJECTED });
+    expect(r.complete).toBe(true);
+    expect(r.outcome).toBe(acq.PREGRADE_OUTCOME.ALL_REJECTED);
+  });
+
+  test('a stubbed/short-circuited grader that records nothing IS a gap', async () => {
+    // Proves the invariant fires rather than inventing a verdict from silence.
+    const { pg, acq: a } = await corridor();
+    expect(acq.reconcilePregrade(a, pg).outcome).toBe(acq.PREGRADE_OUTCOME.OBSERVABILITY_GAP);
+  });
+
+  test('it does not apply when acquisition did not continue', () => {
+    const r = acq.reconcilePregrade({ snapshot_attempt_id: 'a', final: acq.FINAL.THREW, outcome: acq.OUTCOME.EARLY_RETURN_ODDS_ERROR }, null);
+    expect(r.applicable).toBe(false);
+  });
+
+  test('a real corridor run produces a decided state and the SAME attempt id', async () => {
+    // The REAL grader, so admission/dedupe/grade-loop actually record. With a
+    // stubbed grader nothing records and the reconciliation correctly reports a
+    // gap — which is the invariant working, not a decided state.
+    const { pg, acq: a } = await corridor({
+      gradeAndCacheSlate: require('../../src/services/gradeSlateService').gradeAndCacheSlate,
+      grade: async () => null,
+    });
+    expect(pg.snapshot_attempt_id).toBe(a.snapshot_attempt_id);
+    const r = acq.reconcilePregrade(a, pg);
+    expect(r.complete).toBe(true);
+    expect(r.outcome).not.toBe(acq.PREGRADE_OUTCOME.OBSERVABILITY_GAP);
+  });
+});
+
+describe('THE NO-OP RECORDER MUST IMPLEMENT EVERY METHOD', () => {
+  // A missing method throws inside the grade loop, and the enclosing catch
+  // turns that into {written:false,count:0} — a silently empty slate for every
+  // caller that passes no recorder. This shipped once; it must not again.
+  test('NO_PREGRADE covers the full recorder surface', async () => {
+    const real = acq.pregradeRecorder(acq.beginPregrade({ attemptId: 'a', sport: 'mlb' }));
+    const src = fs.readFileSync(path.join(ROOT, 'src/services/gradeSlateService.js'), 'utf8');
+    const i = src.indexOf('const NO_PREGRADE');
+    const block = src.slice(i, src.indexOf('\n});', i) + 4);
+    for (const m of Object.keys(real)) {
+      expect(block).toContain(`${m}(`);
+    }
+  });
+
+  test('grading works with NO recorder passed at all', async () => {
+    const res = await require('../../src/services/gradeSlateService')
+      .gradeAndCacheSlate('mlb', P(2), { cacheSet: async () => {}, grade: async () => null });
+    // Refusals produce no grades, but it must NOT fail with a recorder error.
+    expect(res.error).toBeUndefined();
+  });
+});
+
+describe('ZERO NEW EXTERNAL CALLS', () => {
+  test('the observer adds no provider or schedule call', () => {
+    const snapSrc = fs.readFileSync(path.join(ROOT, 'src/services/snapshotService.js'), 'utf8');
+    // getScheduleWithPitchers is called exactly where the product already called it.
+    expect((snapSrc.match(/getScheduleWithPitchers\(/g) || []).length).toBe(2);
+    expect((snapSrc.match(/buildPlayerTeamIndex\(/g) || []).length).toBe(1);
+    const traceSrc = fs.readFileSync(path.join(ROOT, 'src/services/ops/acquisitionTrace.js'), 'utf8');
+    const code = traceSrc.replace(/\/\*[\s\S]*?\*\//g, '').replace(/(^|[^:])\/\/.*$/gm, '$1')
+      .replace(/s\.replace\([\s\S]*?\);/g, '');
+    for (const f of ['fetch(', 'axios', 'getSchedule', 'getProps', 'getOdds', 'oddsService']) {
+      expect(code).not.toContain(f);
+    }
+  });
+
+  test('a trace-store failure never changes the product outcome', async () => {
+    const { pg } = await corridor({ persistPregradeTrace: async () => { throw new Error('redis down'); } });
+    expect(pg).toBeUndefined();   // nothing stored…
+    // …and the run still completed: no throw escaped runSnapshot.
+  });
+});

tests/unit/pregradeTrace.test.js

@@ -48,8 +48,11 @@ describe('THE STAGE MATRIX', () => {
     expect(trace.admission.rejected_count).toBe(0);
     expect(trace.dedupe.completed).toBe(true);
     expect(trace.dedupe.output_count).toBe(5);
-    expect(trace.grade_loop).toEqual({ candidate_count: 5, reached: true });
-    expect(trace.outcome).toBe(acq.PREGRADE_OUTCOME.READY_FOR_GRADING);
+    expect(trace.grade_loop).toMatchObject({ candidate_count: 5, reached: true });
+    // The loop now proves it ENTERED, which is strictly stronger than a
+    // candidate count, so the terminal state advances past READY_FOR_GRADING.
+    expect(trace.grade_loop.first_gradebestside_started).toBe(true);
+    expect(trace.outcome).toBe(acq.PREGRADE_OUTCOME.GRADE_LOOP_STARTED);
   });
 
   test('ALL_REJECTED — with EXACT reason accounting', async () => {
@@ -74,7 +77,7 @@ describe('THE STAGE MATRIX', () => {
     expect(trace.admission.admitted_count).toBe(4);
     expect(trace.admission.rejected_count).toBe(3);
     expect(trace.admission.rejection_reason_counts.EVENT_PLAYER_TEAM_CONTRADICTION).toBe(3);
-    expect(trace.outcome).toBe(acq.PREGRADE_OUTCOME.READY_FOR_GRADING);
+    expect(trace.outcome).toBe(acq.PREGRADE_OUTCOME.GRADE_LOOP_STARTED);
   });
 
   test('DEDUPE_EMPTY — admitted > 0 but dedupe filters to zero, NOT ALL_REJECTED', async () => {
@@ -84,7 +87,9 @@ describe('THE STAGE MATRIX', () => {
     expect(trace.admission.admitted_count).toBe(5);
     expect(trace.dedupe.input_count).toBe(5);
     expect(trace.dedupe.output_count).toBe(0);
-    expect(trace.outcome).toBe(acq.PREGRADE_OUTCOME.DEDUPE_EMPTY);
+    // Now names WHICH filter emptied it, not merely that it emptied.
+    expect(trace.dedupe.dropped_non_model_book).toBe(5);
+    expect(trace.outcome).toBe(acq.PREGRADE_OUTCOME.DEDUPE_ALL_NON_MODEL_BOOK);
     expect(trace.outcome).not.toBe(acq.PREGRADE_OUTCOME.ALL_REJECTED);
   });
 
@@ -126,7 +131,9 @@ describe('THE STAGE MATRIX', () => {
     await snap2.runSnapshot('mlb', {
       getOdds: async () => ({ sport: 'mlb', props: props(2), provider: 'propline', source: 'cache' }),
       gradeAndCacheSlate: async () => ({ written: false, count: 0 }),
-      eventIdentity: { buildPlayerTeamIndex: async () => { throw new Error('roster down'); },
+      // Roster succeeds so the IDENTITY throw is the one under test; roster now
+      // has its own terminal state and would otherwise (correctly) outrank it.
+      eventIdentity: { buildPlayerTeamIndex: async () => ({ index: {}, stats: { players: 1, teams: 1, failed: 0 } }),
         evidenceIsDateValid: () => false,
         attachEventIdentity: () => { throw new Error('statsapi shape changed'); } },
       mlbAdapter: { getScheduleWithPitchers: async () => [] },
@@ -141,14 +148,14 @@ describe('THE STAGE MATRIX', () => {
     expect(pg).toHaveLength(1);
     expect(pg[0].identity).toBeTruthy();
     expect(pg[0].identity.threw).toBe(true);
-    expect(pg[0].identity.error).toMatch(/statsapi shape changed|roster down/);
-    expect(pg[0].outcome).toBe(acq.PREGRADE_OUTCOME.IDENTITY_STAGE_ERROR);
+    expect(pg[0].identity.error).toMatch(/statsapi shape changed/);
+    expect(pg[0].outcome).toBe(acq.PREGRADE_OUTCOME.EVENT_IDENTITY_STAGE_ERROR);
   });
 
-  test('IDENTITY_STAGE_ERROR outranks everything downstream', async () => {
+  test('EVENT_IDENTITY_STAGE_ERROR outranks everything downstream', async () => {
     const t = acq.beginPregrade({ attemptId: 'a', sport: 'mlb', propsCount: 3 });
     acq.pregradeRecorder(t).identity({ started: true, completed: false, threw: true, error: 'statsapi down' });
-    expect(acq.finishPregrade(t, {}).outcome).toBe(acq.PREGRADE_OUTCOME.IDENTITY_STAGE_ERROR);
+    expect(acq.finishPregrade(t, {}).outcome).toBe(acq.PREGRADE_OUTCOME.EVENT_IDENTITY_STAGE_ERROR);
   });
 
   test('an empty collector alone can NEVER be classified', () => {
@@ -225,7 +232,12 @@ describe('THE OBSERVER DOES NOT TOUCH THE PROPS', () => {
 
   test('the recorder default is a frozen no-op, so existing callers are identical', () => {
     const src = fs.readFileSync(path.join(ROOT, 'src/services/gradeSlateService.js'), 'utf8');
-    expect(src).toMatch(/const NO_PREGRADE = Object\.freeze\(\{ identity\(\) \{\}, admission\(\) \{\}, dedupe\(\) \{\}, gradeLoop\(\) \{\} \}\)/);
+    // Now multi-line and covering the full recorder surface; match the shape,
+    // not the exact one-line form.
+    expect(src).toMatch(/const NO_PREGRADE = Object\.freeze\(\{/);
+    for (const m of ['identity', 'admission', 'dedupe', 'gradeLoop', 'gradeStarted', 'firstOnGraded']) {
+      expect(src).toMatch(new RegExp(`${m}\\(\\) \\{\\}`));
+    }
     expect(src).toMatch(/const pregrade = opts\.pregrade \|\| NO_PREGRADE;/);
   });
 });
@@ -309,7 +321,7 @@ describe('THE TRACE IS ACTUALLY PERSISTED BY THE REAL PATH', () => {
     expect(pgStored[0].snapshot_attempt_id).toBe(acqStored[0].snapshot_attempt_id);
     expect(pgStored[0].input_props_count).toBe(3);
     expect(pgStored[0].admission.input_count).toBe(3);
-    expect(pgStored[0].outcome).toBe(acq.PREGRADE_OUTCOME.READY_FOR_GRADING);
+    expect(pgStored[0].outcome).toBe(acq.PREGRADE_OUTCOME.GRADE_LOOP_STARTED);
   });
 });
 

tests/unit/retentionIdentity.test.js

@@ -106,7 +106,9 @@ describe('CANONICAL EVENT AVAILABILITY BY ROW CLASS', () => {
     // wraps it in try/catch to record and rethrow, which changed `const gate =`
     // into `gate = `. The invariant is that admission runs on (props, sport).
     expect(gs).toMatch(/gate = admitForGrading\(props, sport\)/);
-    expect(gs).toMatch(/dedupeProps\(gate\.admitted, limit\)/);
+    // The call gained an optional diagnostic stats object; match the call, not
+    // its exact arity.
+    expect(gs).toMatch(/dedupeProps\(gate\.admitted, limit/);
     expect(gs).not.toMatch(/dedupeProps\(gate\.rejected/);
   });