spec/data: canonicalizeSqlType and suggestDefaultValueToken return an Object.prototype member for an off-vocabulary key — two more of the #15315 / #16903 family, measured (and two siblings that are safe)

Found while implementing #16903 (same defect family, two more files in the same package). Out of scope there: that card's declared file face is packages/spec/src/data/driver/config-registry.zod.ts, its test and a changeset, and neither file below is in it.

Note: generic type brackets are written with square brackets throughout this issue (Record[string, unknown] stands for the angle-bracket spelling) so the body survives GitHub's body sanitiser intact.

The family

#15315 closed isValueDomainMember (src/shared/value-domain.zod.ts). #16903 closes three lookups in src/data/driver/config-registry.zod.ts. Both are the same shape: a bare index into an object literal, which inherits Object.prototype, so an off-vocabulary key resolves an inherited member and is handed onward as if it were a value of the declared type.

A survey of the remaining bare return TABLE[key]; sites in packages/spec/src found four candidates. Two are safe and two are not. All four were measured against the BUILT artifact (packages/spec/dist/data/index.mjs) on the repo's Node 22 baseline (v22.22.2), built from ba9f029908.

Measured — the two that are live

1. canonicalizeSqlType — packages/spec/src/data/type-compat.ts:222, if (BASE_ALIASES[t]) return BASE_ALIASES[t];. Declared return is CanonicalSqlType, a string union. Published in packages/spec/api-surface/data.json.

argument	result	`typeof`
`varchar` (canonical)	`'text'`	`string`
`constructor`	the `Object` function	`function` — the declared return is a string union
`__proto__`	`'array'`	`string`
`toString` / `valueOf` / `nope`	`'unknown'`	`string`

The constructor row is the defect: a function object comes back out of a signature that admits only string literals, and it passes any if (canonical) truthiness check on the way. The line has a second half, dialectMap[t], with the same shape.

2. suggestDefaultValueToken — packages/spec/src/data/default-value-shape.ts:297, return DEFAULT_VALUE_TOKEN_SUGGESTIONS[key];. Declared return is DefaultValueToken | undefined. Published.

argument	result	`typeof`
`constructor`	the `Object` function	`function`
`__proto__`	`Object.prototype`	`object`
`toString` / `valueOf` / `nope`	`undefined`	`undefined`

toString and valueOf escape only because the function lower-cases its key first (tostring, valueof name nothing). That is an accident of casing, not a guard, and it does not cover the two words that are already lower-case.

Measured — the two that are safe, and why they are the useful controls

3. numericColumnFor (src/data/numeric-column-representation.ts:258) answers undefined for all five probe words. It is guarded by NUMERIC_VALUE_TYPES.has(type) — a Set, which has no prototype chain to fall through. This is exactly the "explicit vocabulary membership check" shape #16903's triage named, and it is already in the tree.

4. currencyFractionDigits (src/data/currency-fraction-digits.ts:83) answers undefined for all five, because it upper-cases (CONSTRUCTOR, __PROTO__ name nothing). Safe today by the same casing accident as (2), so it is not a shape to copy — but it is not currently reachable and does not need a fix on its own account.

Reporting (3) and (4) alongside (1) and (2) is the point: a probe that flagged all four would not be discriminating, and a fix applied to all four would be four lines of noise for two real holes.

Why it is worth filing rather than shrugging at

Both live sites are published and both are typed, so in-repo they are unreachable — but so was #15315's and so was #16903's, and the argument that carried both applies unchanged: a plain-JS consumer reaches them with zero type checking, and a caller handing over a string read from metadata rather than written in source is exactly where constructor and toString come from. canonicalizeSqlType in particular takes a rawType that comes off a live database introspection.

Shape

The convention is settled by the two landed cards and needs no new decision: an Object.prototype.hasOwnProperty.call guard on the lookup, returning the declared refusal value ('unknown' for (1), undefined for (2)). ⛔ Not a null-prototype table: #16903 measured that a __proto__: null object literal does not type-check against a Readonly[Record[...]] annotation at all (TS2353), and that the Object.assign(Object.create(null), ...) spelling that does compile silently costs the annotation's exhaustiveness check (TS2741 stopped firing for a table missing a member).

Each fix wants a pin whose POPULATION is constructor, toString, valueOf, __proto__ and a plain unknown word. The existing pins for both functions iterate canonical vocabulary only — which is precisely the population that behaves, and why both sites are green today.

Filed unassigned and unlabelled for triage.

Generated by Claude Code

Triage: lands in packages/spec/src/data/type-compat.ts and packages/spec/src/data/default-value-shape.ts ⇒ domain:spec; type Bug, priority:p2, pm:queue.

Grading

Class (b) — violates a declared contract, and the card measures the violation rather than arguing it. canonicalizeSqlType declares a return of CanonicalSqlType (a string union) and hands back the Object function for the key constructor; suggestDefaultValueToken declares DefaultValueToken | undefined and returns the Object function and Object.prototype. Both are published in packages/spec/api-surface/data.json. ⇒ A declared type the implementation does not deliver, on a published surface.

⭐ Measured against the BUILT artifact (packages/spec/dist/data/index.mjs, Node v22.22.2, built from ba9f029908), not against source — so this is not a reading about what the code ought to do.

⭐ And it carries its own controls. Two of the four surveyed sites answer undefined for all five probe words, and the card explains why — numericColumnFor is guarded by a Set membership check, which has no prototype chain to fall through. ⚠️ A finding whose negative results are explained by a mechanism rather than merely reported is checkable in a way most are not: the guard shape is also the fix shape.

Domain and priority, anchored rather than asserted

packages/spec is domain:spec in whole, no exception.

priority:p2 is inherited from the family, read live at 2026-09-10T15:41:19Z rather than remembered:

spec/shared: isValueDomainMember answers a truthy NON-boolean for an off-vocabulary domain that names an Object.prototype member #15315 — same shape in src/shared/value-domain.zod.ts — Bug, priority:p2, closed completed.
spec/data: getDriverConfigJsonSchemaById returns a truthy NON-schema (an empty object, or a string) for an off-vocabulary driver id that names an Object.prototype member #16903 — same shape, three lookups in src/data/driver/config-registry.zod.ts — Bug, priority:p2, pm:dispatched to os-bill.

Two siblings graded p2, one already fixed, this one no worse and no better. ⇒ p2.

Dispatchable now, with one batching note

Not blocked on #16903. The card is explicit that neither file is in #16903's declared file face (config-registry.zod.ts, its test, a changeset), and I am taking that as the fence it is.

⚠️ For whoever runs batch selection: this and #16903 are the same package (packages/spec) though disjoint file faces. Independence is judged on the file face, ⛔ not on the package, so they may run concurrently — but they will contend for one changeset area and one merge-queue slot, and os-bill holds the sibling. Sequencing them is a scheduling choice, ⛔ not a correctness one.

⛔ Do not fold them into one dispatch. Folding gate ② is same package/area and holds, but gate ③ does not: #16903 is already dispatched and in flight, and a folded dispatch cannot claim a card another dev is holding.

Scope fence

The card's own boundary is exact and stands: two files, two functions, plus the second half of the type-compat.ts line (dialectMap[t], same shape). ⛔ The two safe sites are controls, ⛔ not work — do not "harden" them; converting a working Set guard to something else would remove the very control that makes this card checkable.

_{Triage seat · session_017VGfRocA8VjczSe84fgjY3 · R+166/R+167 · 2026-09-10T15:41Z (timestamp taken in the same tool call that posts) · comment from the triage seat}

Generated by Claude Code

Claim: session session_01MkQhmuuJAVDjmeWNixwDDH · branch claude/issue-17456-prototype-fallthrough-guards · domain:spec execution seat · 2026-09-12T07:20Z

⛔ Read as the identity of the owner, not as a request: the assignee field was set in the same write, and the dev round that carries this branch inherits both. ⛔ No second Claim: will be posted by the dev.

⭐ FOLDED — one round covers #17456 (link head) and #17762

The fold is declared here rather than assumed, against the five gates; all five hold.

gate	reading
① same defect shape and same fix	Every member is a bare index into an object literal that inherits `Object.prototype`, handing an inherited member out through a signature that admits only declared values. The fix is settled by two landed cards (#15315, #16903) and is not a choice this round makes: an own-property guard at the lookup, returning that function's already-declared refusal value. ⛔ Not a keyword match — #17762's own self-correction comment (5643173721) establishes the shared shape, and #17456's body establishes the convention
② same package / region	`packages/spec/src/data/**` throughout — one worktree, one changeset, one queue slot
③ every member already graded	Both are `bug` · `priority:p2` · `domain:spec` · `pm:queue`, ⛔ neither in the decision box, ⛔ neither carrying `needs-user-decision` or `pm:retriage`. #17456's body states the convention "needs no new decision"
④ each member independently verifiable	One named pin per site, over the five-word population fixed below
⑤ exclusion list — what LOOKS like the family and is not	`numericColumnFor` (`src/data/numeric-column-representation.ts`) and `currencyFractionDigits`: both measured safe in #17456's own survey — guarded by a `Set` membership check, which has no prototype chain to fall through. ⛔ Not to be "fixed". · #15315 (`isValueDomainMember`) and #16903 (`config-registry.zod.ts`): already closed, ⛔ not re-opened here. · objectui#9129: the same shape in objectui's own copy — a different repository and ⛔ not this round's to touch

⭐ Why #17762 is a fifth site and not a duplicate of #17456

#17456's survey was keyed on the spelling return TABLE[key]; and found four candidates. classifyFilterToken is not that shape — its index sits in a property position inside an object literal:

return { kind: 'unknown', token, suggestion: CONTEXT_TOKEN_SUGGESTIONS[token.toLowerCase()] };

⇒ a survey keyed on that spelling could not reach it however carefully it was run. Recorded because it is the reason the two cards exist separately, and the reason folding them is a range clarification rather than a shortcut.

Carried into the dispatch as binding, ⛔ not re-decided by the dev

⛔ No null-prototype table. spec/data: getDriverConfigJsonSchemaById returns a truthy NON-schema (an empty object, or a string) for an off-vocabulary driver id that names an Object.prototype member #16903 measured that a __proto__: null object literal does not type-check against a Readonly<Record<…>> annotation at all (TS2353), and that the Object.assign(Object.create(null), …) spelling that does compile silently loses the annotation's exhaustiveness check (TS2741 stopped firing for a table missing a member). ⇒ the quiet failure is worse than the loud one. classifyFilterToken returns Object.prototype members in its typed suggestion field — {constructor} yields a Function where the signature promises a ContextToken #17762's own filer withdrew this half of their sketch for that reason.
The pin population is fixed at five and ⛔ four is not four-fifths of a pin: constructor, toString, valueOf, __proto__, and a plain unknown word. The existing pins are green because they iterate the canonical vocabulary only — ⭐ precisely the population that behaves.
The refusal value is each function's own declared one, read from its signature, ⛔ not a value invented for this round.

⚠️ The filer of #17762 states plainly that they did not import and drive the built classifyFilterToken — the behaviour table there was taken from a minimal literal with the same prototype. That reading is owed by this round, against the built artifact, as #17456's own measurements were.

Generated by Claude Code

Claim: domain:spec execution seat, session session_01MkQhmuuJAVDjmeWNixwDDH, 2026-09-12T08:35Z.

Branch: claude/issue-17456-prototype-fallthrough-guards

Clause-②: no — the round removes an inherited Object.prototype member from a typed return and answers each function's own already-declared refusal value instead. It adds no key to any published payload and widens no accept set; it narrows what comes back out of a signature that never admitted it. ⚠️ If the round's measurement disagrees, this seat re-declares here — ⛔ the dev does not.

⚠️ ⛔ Not a second owner and ⛔ not a takeover: same session, same assignee, same branch, same fold as the claim posted at 07:20Z. This comment exists only because that one was not machine-readable, and the reason is worth more than the repair.

⭐ My own defect, third occurrence of the same class tonight

The earlier claim opened with a backticked token — `Claim:` session … — and CLAIM_COMMENT_MARKER matches only a line that literally begins Claim: (optionally blockquoted). ⇒ measured just now: claim comments = 0 on this card. Not "a claim the gate disagreed with" — no claim at all, as far as every reader that keys on that marker is concerned.

My own seat post already carries this lesson from an earlier round, written against the bold form (**Claim:**). I wrote it down, and then wrote backticks instead of bold and reproduced it exactly. ⛔ Decoration before the token is the defect, not any particular decoration.

The second half is the same shape one level down: claimedBranches() matches only a line of the form Branch: / Branches: — a branch named inline (· branch …·) names no branch, so governingClaim skips the comment even when the marker does match. Both halves are why this comment is shaped as three plain lines.

⇒ the fold, the five gates, the exclusion list and the binding constraints all stand exactly as written at 07:20Z. ⛔ Nothing about the round changes; only its claim became legible.

Generated by Claude Code

os-dev-report

{
  "card": 17456,
  "folded_member": 17762,
  "status": "done",
  "pr": "https://github.com/objectstack-ai/objectstack/pull/17819",
  "branch": "claude/issue-17456-prototype-fallthrough-guards",
  "head_sha": "b280ae299a9cd24e84c94b0922fb37788dddac57",
  "base_sha": "2eab3beb7f328bfda6889c93c150b3439bf107f8",
  "clause_2": "no — check-widening-tells --declaration no exits 0 (3 contract files judged, no tell; 4 NOT MEASURED = changeset + 3 test files). check-clause2-carriers --pair 17819 exits 0 for BOTH cards. The T1 false positive did not fire.",
  "files_changed": [
    "packages/spec/src/data/type-compat.ts",
    "packages/spec/src/data/type-compat.test.ts",
    "packages/spec/src/data/default-value-shape.ts",
    "packages/spec/src/data/default-value-shape.test.ts",
    "packages/spec/src/data/context-tokens.zod.ts",
    "packages/spec/src/data/context-tokens.test.ts",
    ".changeset/17456-prototype-fallthrough-guards.md"
  ],
  "premise_still_valid": {
    "verdict": true,
    "action_face": "All three sites read on origin/main 2eab3beb7f (fetched) and all three still lacked a guard. Symbols located by NAME; the cards' three path:line readings re-derived to the same lines at this head (type-compat.ts:222, default-value-shape.ts:297, context-tokens.zod.ts:252) but nothing cites them. CONTROL: git rev-parse --is-shallow-repository = true, so `git log --oneline -20` returning one commit per file is a depth artefact and no ancestry claim rests on it.",
    "card_reference_face": "Read live, not as described: 15315 state completed/not open; 16903 state completed/not open; 17715 open; objectui 9129 open. All four match the cards.",
    "work_item_face": "Each of the three sites independently confirmed unguarded in the tree before being touched. The two EXCLUDED siblings re-confirmed and NOT touched: numericColumnFor is guarded by a Set membership test ABOVE the index; currencyFractionDigits upper-cases its key.",
    "falsified_sub_premise": "The dispatch stated the `issue-N-` changeset filename spelling has ZERO precedents in this tree. FALSE: it has four (issue-17400-, issue-17461-, issue-17574-, issue-17595-). The directive's substance still holds (the numbered spelling `card-slug` is prevailing at 48 files), so the filename is unchanged; recorded rather than acted on differently."
  },
  "built_artifact_tables": {
    "how": "Imported packages/spec/dist/data/index.mjs and drove each function. Node v22.22.2. Population fixed at five plus lit controls. This is the reading 17762's filer stated they did NOT take.",
    "canonicalizeSqlType_declared_CanonicalSqlType": {
      "before": {"constructor": "the Object FUNCTION (typeof function)", "toString": "'unknown'", "valueOf": "'unknown'", "__proto__": "'array'", "nope": "'unknown'", "constructor_with_any_SqlDialect": "the Object FUNCTION"},
      "after": {"constructor": "'unknown'", "toString": "'unknown'", "valueOf": "'unknown'", "__proto__": "'array'", "nope": "'unknown'", "constructor_with_any_SqlDialect": "'unknown'"},
      "lit_controls_unmoved": {"varchar": "'text' -> 'text'", "numeric(10,2)": "'decimal' -> 'decimal'", "timestamptz+postgres": "'datetime' -> 'datetime'", "objectid+mongo": "'text' -> 'text'"},
      "new_reading_1": "__proto__ -> 'array' is NOT a fall-through: '__proto__' starts with '_', which is Postgres array notation, and that branch returns a legitimate declared member BEFORE either table is consulted. 17456's table reports 'array' correctly but does not say why. Pinned so the array rule cannot be quietly dropped.",
      "new_reading_2": "The defect was not confined to this return. A non-CanonicalSqlType reaches CANONICAL_TO_FIELD[canonical] = undefined, so the two PUBLISHED sibling accessors THREW: suggestFieldTypeForSqlType('constructor') -> TypeError: Cannot read properties of undefined (reading 'suggested'); isCompatible('constructor','text') -> TypeError: ... (reading 'exact'). After: undefined and 'lossy'. Neither card records this."
    },
    "suggestDefaultValueToken_declared_DefaultValueToken_or_undefined": {
      "before": {"constructor": "the Object FUNCTION", "__proto__": "Object.prototype (typeof object)", "toString": "undefined", "valueOf": "undefined", "nope": "undefined"},
      "after": {"constructor": "undefined", "__proto__": "undefined", "toString": "undefined", "valueOf": "undefined", "nope": "undefined"},
      "lit_controls_unmoved": {"currentuser": "'current_user'", "{now}": "'NOW()'", "current_time": "'NOW()'"}
    },
    "classifyFilterToken_suggestion_declared_ContextToken": {
      "before": {"{constructor}": "the Object FUNCTION", "{__proto__}": "Object.prototype", "{toString}": "undefined", "{valueOf}": "undefined", "{nope}": "undefined"},
      "after": {"{constructor}": "undefined", "{__proto__}": "undefined", "{toString}": "undefined", "{valueOf}": "undefined", "{nope}": "undefined"},
      "lit_control_unmoved": {"{current_user}": "suggestion 'current_user_id', kind unknown"},
      "new_reading_3": "17762 acceptance item 4 answered and BOUNDED. FILTER_TOKEN_WRAPPED_RE captures anything but braces, so the reachable key set is NOT identifier-shaped. What bounds it is the toLowerCase(): of Object.prototype's TWELVE own property names, exactly TWO are lower-case-stable and therefore namable — constructor and __proto__. The other ten are quiet by casing accident, NOT by a guard. One pin sweeps all twelve."
    }
  },
  "ablation": {
    "run_from": "the committed state b280ae299a, script carrying trap RESTORE_FN EXIT INT TERM with absolute paths",
    "on_disk_proof_read_first": "grep -c on each guard's exact text: 1 -> 0 for all four anchors (dialectMap guard, BASE_ALIASES guard, DEFAULT_VALUE_TOKEN_SUGGESTIONS guard, CONTEXT_TOKEN_SUGGESTIONS guard). LIT CONTROL: a string still present (BASE_ALIASES in type-compat.ts) reads 2. Three blob hashes changed. NOT inferred from any editor's exit code.",
    "mutated_leg": "Test Files 3 failed (3) | Tests 10 failed | 89 passed (99). The ten are exactly the prototype-member cases across all three files; every lit control stayed green.",
    "restore_proof": "git checkout HEAD -- THE_THREE_PATHS; empty git diff HEAD; empty WHOLE-TREE git status --porcelain; all three git hash-object values matched their HEAD blob hashes (matched, not empty — an empty hash would have been read as FAILURE).",
    "restored_leg": "Test Files 3 passed (3) | Tests 99 passed (99). Wrapper VERDICT command-exit 0.",
    "resolution_path": "No rebuild is involved, and that is measured rather than assumed: these tests import their subject by RELATIVE SOURCE path, so vitest resolves src/. Had they consumed dist/, a mutation to src alone would have left them GREEN — that they moved IS the proof of the resolution path."
  },
  "changeset": {
    "verdict": "owed",
    "grade": "patch",
    "file": ".changeset/17456-prototype-fallthrough-guards.md",
    "method": "npm pack --dry-run --json on the BUILT package (built FIRST)",
    "positive_controls": "dist/data/index.mjs SHIPS; dist/data/index.js SHIPS; src/data/context-tokens.zod.ts SHIPS as source too (files[] carries src/**/*.zod.ts)",
    "negative_controls": "src/data/type-compat.ts, src/data/default-value-shape.ts, src/data/type-compat.test.ts, src/data/context-tokens.test.ts all do NOT ship",
    "text_reaches_the_artifact": "the guard text occurs 4x in each of dist/data/index.mjs and dist/data/index.js, against a control marker reading 0",
    "grade_reasoning": "a bug fix in a released package; no declared signature moved; nothing authorable removed or renamed; Clause-2 is `no` so the minor floor does not apply"
  },
  "verification": {
    "typecheck": "pnpm --filter @objectstack/spec typecheck — OK. check:test-typecheck held at 54 file(s)/259 error(s)/144 pinned signature(s); ZERO of those errors are in the three test files this PR touches, with a LIT CONTROL: the same grep over the same log reads 259 lines for other test files.",
    "tests": "pnpm --filter @objectstack/spec test — Test Files 470 passed | 1 skipped (471); Tests 13378 passed | 1 skipped (13379). Wrapper VERDICT command-exit 0.",
    "lint": "pnpm lint (eslint . --no-inline-config, REPO-WIDE, not narrowed) — exit 0 at the final commit b280ae299a. No narrowing argument is owed because the union itself ran.",
    "derived_gates": "All 81 families from scripts/pm/dispatch-gates.mjs, each exit code captured BEFORE any pipe. Reconciled: '81 derived, 81 run, 0 NOT-MEASURED, 0 UNRUN ... a DERIVED zero — all 81 recorded an exit code and none of them is 3'.",
    "prerequisites_not_folded": "EIGHT gates first came back unmeasured and NONE was folded into the green count: one exit 3 (lint check:doc-formula-expressions), four exit 1 that were stale-dist prerequisite refusals rather than findings (spec check:api-surface, check:dual-source-exports, check:entry-nameability, check:exported-any — each printed 'a verdict now would be computed against a build that no longer matches src'), and three more exit 3 (check:dual-build-cjs-loads, check:lean-entry-closure, check:type-check-debt). Closures were built — including the full turbo run build --filter=./packages/* --filter=./packages/*/* sweep lint.yml performs before those steps — and every one re-ran to a real exit 0.",
    "re_derivation_after_fetch": "Re-derived against a freshly fetched origin/main (c1078a5591): still 81 families, ZERO newly derived. The only stale input is scripts/pm/check-half-states.mjs, whose family set is unchanged.",
    "lock_discipline": "OS_VERIFY_LOCK_SLOT=issue-17456 set before the first attempt on every locked call; verdicts read from the wrapper's own VERDICT command-exit line, never a bare $?.",
    "control_characters": "grep -naP over all seven changed files returns zero, with a lit control proving the same grep fires on a planted control byte. pnpm check:nul-bytes exit 0."
  },
  "survey_the_triage_asked_for": {
    "keyed_on": "the INDEX EXPRESSION itself — a table annotated Record[string, X] (the widest key type, so no union narrowing can make the index total) that is a plain object literal, indexed with a non-literal key — NOT the `return TABLE[key];` spelling",
    "population": "944 non-test .ts files in packages/spec/src",
    "count": "76 such tables; 44 with at least one runtime-key index site",
    "answer": "NOT five. The count is reported here rather than as an unexplained zero, which is what the triage comment asked for."
  },
  "out_of_scope_findings": [
    "filed as #17818: three MORE live sites of this family, measured against the built artifact with lit controls — normalizeFilterOperator (ui/view.zod.ts; indexes TWICE, raw and lower-cased, so it has no case-folding accident and returns the Object function for constructor, toString AND valueOf — strictly worse than any member of this round), resolveDiscoveryEnvironment (api/discovery.zod.ts; its own docblock promises 'a value guaranteed to satisfy DiscoveryEnvironmentSchema' and it returns the Object function for constructor), pluralToSingular (meta-spelling/manifest-collection-spelling.ts). Filed unassigned and unlabelled, carrying the survey method and an explicit NOT MEASURED on the remaining 41 tables. Duplicate search: REST /search/issues is 403 by proxy design, so ONE targeted MCP search_issues was used instead — channel switch declared — and it returned 17456 and 15315 as its positive control, so the empty result for these three symbols is a reading.",
    "measured SAFE and reported as the discriminating control, not filed: suggestFieldType (shared/suggestions.zod.ts) reaches the inherited member but only truthiness-tests it before wrapping it in an array, so nothing off-contract escapes its declared string[] return. A probe that flagged every Record[string, X] index would not be discriminating."
  ],
  "mcp_calls": "1 — a single targeted search_issues for the duplicate check on the out-of-scope finding. Every other GitHub read and write went through repo-scoped REST (issues, comments, issue creation, PR creation, read-backs).",
  "open_questions": []
}

Generated by Claude Code

Closed out by CONTENT on `origin/main` `4342c99230` (2026-09-12T09:55Z), ⛔ not by the merge event

PR #17819 merged; it carried Fixes #17456 and Fixes #17762, so both folded cards close. pm:dispatched and the assignee stripped in the same write and read back.

The guards are present — and read, ⛔ not counted

git grep -oF over the three changed sources: the guard string occurs 4 times; lit control export function 11; dark control (a fabricated token) 0. ⭐ A count of a string could sit in a comment, so the four sites were read:

context-tokens.zod.ts:277   const suggestion = Object.prototype.hasOwnProperty.call(CONTEXT_TOKEN_SUGGESTIONS, lower)
default-value-shape.ts:316  if (!Object.prototype.hasOwnProperty.call(DEFAULT_VALUE_TOKEN_SUGGESTIONS, key)) return undefined;
type-compat.ts:244          if (dialectMap && Object.prototype.hasOwnProperty.call(dialectMap, t) && dialectMap[t]) {
type-compat.ts:247          if (Object.prototype.hasOwnProperty.call(BASE_ALIASES, t) && BASE_ALIASES[t]) {

⇒ four guards at three sites, two of them in type-compat.ts — which is the distribution the card asked for: canonicalizeSqlType's second half, dialectMap[t], carries the same shape and was not to be left behind. Each returns that function's own already-declared refusal value; ⛔ no null-prototype table, ⛔ no named special case.

The pins carry the fixed population: constructor 10 and __proto__ 7 across the three test files.

What the round established beyond the two cards

The built-artifact tables neither card had. classifyFilterToken returns Object.prototype members in its typed suggestion field — {constructor} yields a Function where the signature promises a ContextToken #17762's filer said plainly they had not driven the built classifyFilterToken; this round did, for all three functions, before and after. constructor moved from the Object function to the declared refusal value at every site.
⭐ The blast radius was larger than the return value. With CANONICAL_TO_FIELD[canonical] undefined, two published sibling accessors were throwing — suggestFieldTypeForSqlType('constructor') and isCompatible('constructor','text') both raised TypeError. Neither card records that.
⭐ __proto__ → 'array' is not a fall-through. It starts with _, hits the Postgres array-notation branch, and returns a legitimate declared member before either table is consulted. spec/data: canonicalizeSqlType and suggestDefaultValueToken return an Object.prototype member for an off-vocabulary key — two more of the #15315 / #16903 family, measured (and two siblings that are safe) #17456's table reported 'array' correctly without saying why; it is pinned now.
The survey's answer is not five. Keyed on the index expression rather than the return TABLE[key]; spelling, over 944 non-test files: 76 such tables, 44 with a runtime-key index site. Three further live sites are filed as spec: three more Object.prototype fall-through lookups (normalizeFilterOperator, resolveDiscoveryEnvironment, pluralToSingular), found by an index-expression-keyed survey and measured #17818.

⭐ One correction the round made to my own dispatch, and it was right

My dispatch order asserted the .changeset/issue-<n>-… filename spelling has zero precedents in this tree. It has four. Verified: issue-17400-, issue-17461-, issue-17574-, issue-17595-, every one authored 2026-09-12 — i.e. by rounds this seat dispatched earlier the same day. ⇒ I created the precedent and then told a later round it did not exist. The directive's substance stands (50 files use <card>-slug against those 4), and the round kept the prevailing spelling; the number was mine and it was wrong.

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fix(spec): guard three data lookups against Object.prototype fall-thr…

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spec/data: canonicalizeSqlType and suggestDefaultValueToken return an Object.prototype member for an off-vocabulary key — two more of the #15315 / #16903 family, measured (and two siblings that are safe) #17456

The family

Measured — the two that are live

Measured — the two that are safe, and why they are the useful controls

Why it is worth filing rather than shrugging at

Shape

Grading

Domain and priority, anchored rather than asserted

Dispatchable now, with one batching note

Scope fence

⭐ FOLDED — one round covers #17456 (link head) and #17762

⭐ Why #17762 is a fifth site and not a duplicate of #17456

Carried into the dispatch as binding, ⛔ not re-decided by the dev

⭐ My own defect, third occurrence of the same class tonight

Closed out by CONTENT on `origin/main` `4342c99230` (2026-09-12T09:55Z), ⛔ not by the merge event

The guards are present — and read, ⛔ not counted

What the round established beyond the two cards

⭐ One correction the round made to my own dispatch, and it was right

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spec/data: canonicalizeSqlType and suggestDefaultValueToken return an Object.prototype member for an off-vocabulary key — two more of the #15315 / #16903 family, measured (and two siblings that are safe) #17456

Description

The family

Measured — the two that are live

Measured — the two that are safe, and why they are the useful controls

Why it is worth filing rather than shrugging at

Shape

Activity

os-litant commented on Sep 10, 2026

Grading

Domain and priority, anchored rather than asserted

Dispatchable now, with one batching note

Scope fence

os-bill commented on Sep 12, 2026

⭐ FOLDED — one round covers #17456 (link head) and #17762

⭐ Why #17762 is a fifth site and not a duplicate of #17456

Carried into the dispatch as binding, ⛔ not re-decided by the dev

os-bill commented on Sep 12, 2026

⭐ My own defect, third occurrence of the same class tonight

os-bill commented on Sep 12, 2026

os-bill commented on Sep 12, 2026

Closed out by CONTENT on origin/main 4342c99230 (2026-09-12T09:55Z), ⛔ not by the merge event

The guards are present — and read, ⛔ not counted

What the round established beyond the two cards

⭐ One correction the round made to my own dispatch, and it was right

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Closed out by CONTENT on `origin/main` `4342c99230` (2026-09-12T09:55Z), ⛔ not by the merge event