fix: enforce exact local evidence defaults

scripts/lib/local-policy-evidence.ts

@@ -2,6 +2,8 @@ import {
   dependencyDiffArtifactSchema,
   dependencyInventoryArtifactSchema,
   licenseReportArtifactSchema,
+  supplyChainVerificationArtifactSchema,
+  vulnerabilityReportArtifactSchema,
 } from "../contracts/release-artifacts.ts";
 import type { DistOutput } from "./release-candidate.ts";
 import {
@@ -13,6 +15,60 @@ import {
 
 type Document = Record<string, unknown>;
 
+export const LOCAL_SUPPLY_CHAIN_UNVERIFIED_DEFAULTS = Object.freeze({
+  promotionStatus: "FAIL_UNVERIFIED" as const,
+  vulnerabilityStatus: "FAIL_UNVERIFIED" as const,
+  provenanceAttestationStatus: "FAIL_UNVERIFIED" as const,
+});
+
+export function verifyLocalSupplyChainDefaults(stored: unknown): string[] {
+  const parsed = supplyChainVerificationArtifactSchema.safeParse(stored);
+  if (
+    !parsed.success ||
+    parsed.data.promotionStatus !==
+      LOCAL_SUPPLY_CHAIN_UNVERIFIED_DEFAULTS.promotionStatus ||
+    parsed.data.vulnerabilityStatus !==
+      LOCAL_SUPPLY_CHAIN_UNVERIFIED_DEFAULTS.vulnerabilityStatus ||
+    parsed.data.provenanceAttestationStatus !==
+      LOCAL_SUPPLY_CHAIN_UNVERIFIED_DEFAULTS.provenanceAttestationStatus
+  ) {
+    return [
+      "supply-chain verification provider defaults are not local FAIL_UNVERIFIED",
+    ];
+  }
+  return [];
+}
+
+export function createLocalVulnerabilityReport(lockfileSha256: string) {
+  return vulnerabilityReportArtifactSchema.parse({
+    schemaVersion: 1,
+    provider: "UNCONFIGURED",
+    scannedLockfileSha256: lockfileSha256,
+    status: "FAIL_UNVERIFIED",
+    findings: [],
+    exceptionsApplied: [],
+    failures: ["external vulnerability provider report is missing"],
+    blocking: [],
+  });
+}
+
+export function compareStoredLocalVulnerabilityReport(
+  lockfileSha256: string,
+  stored: unknown,
+): string[] {
+  const parsed = vulnerabilityReportArtifactSchema.safeParse(stored);
+  if (
+    !parsed.success ||
+    supplyChainDigest(parsed.data) !==
+      supplyChainDigest(createLocalVulnerabilityReport(lockfileSha256))
+  ) {
+    return [
+      "local vulnerability report does not match exact unconfigured defaults",
+    ];
+  }
+  return [];
+}
+
 export function recomputeDependencyEvidence(input: Readonly<{
   inventory: unknown;
   baseline: unknown;