fix: harden repository coverage evidence

scripts/check-risk-coverage.ts

@@ -1,6 +1,9 @@
-import { mkdir, readFile, writeFile } from "node:fs/promises";
 import path from "node:path";
 
+import {
+  readRiskCoverageInput,
+  writeRiskCoverageArtifactAtomic,
+} from "./lib/risk-coverage-files.ts";
 import {
   buildProductionModuleInventory,
   evaluateRiskCoverage,
@@ -18,71 +21,56 @@ function requiredArgument(name: string, fallback: string): string {
   return value;
 }
 
-function parseChangedFiles(value: unknown): readonly string[] {
-  if (
-    !Array.isArray(value) ||
-    value.some((entry) => typeof entry !== "string") ||
-    new Set(value).size !== value.length
-  ) {
-    throw new TypeError("changed files input must be an array of unique paths");
-  }
-  return Object.freeze([...value] as string[]);
-}
-
 const repositoryRoot = path.resolve(
   requiredArgument("--repository-root", process.cwd()),
 );
-const policyPath = requiredArgument(
-  "--policy",
-  "config/testing/risk-coverage.json",
-);
-const summaryPath = requiredArgument(
-  "--summary",
-  "artifacts/tests/coverage/coverage-summary.json",
-);
+const policyInput = await readRiskCoverageInput({
+  repositoryRoot,
+  relativePath: requiredArgument(
+    "--policy",
+    "config/testing/risk-coverage.json",
+  ),
+  label: "policy",
+});
+const summaryInput = await readRiskCoverageInput({
+  repositoryRoot,
+  relativePath: requiredArgument(
+    "--summary",
+    "artifacts/tests/coverage/coverage-summary.json",
+  ),
+  label: "summary",
+});
 const artifactPath = requiredArgument(
   "--artifact",
   "artifacts/quality/risk-coverage.json",
 );
-const changedFilesPath = argumentValue("--changed-files");
 const policy = parseRepositoryRiskCoveragePolicy(
-  JSON.parse(await readFile(path.resolve(repositoryRoot, policyPath), "utf8")) as unknown,
+  JSON.parse(policyInput.text) as unknown,
 );
 const inventory = await buildProductionModuleInventory({
   repositoryRoot,
   generatedPaths: policy.generatedPaths,
 });
-const changedFiles = changedFilesPath
-  ? parseChangedFiles(
-      JSON.parse(
-        await readFile(path.resolve(repositoryRoot, changedFilesPath), "utf8"),
-      ) as unknown,
-    )
-  : [];
 const result = evaluateRiskCoverage({
   repositoryRoot,
   inventory,
   policy,
-  summary: JSON.parse(
-    await readFile(path.resolve(repositoryRoot, summaryPath), "utf8"),
-  ) as unknown,
-  changedFiles,
+  summary: JSON.parse(summaryInput.text) as unknown,
+});
+await writeRiskCoverageArtifactAtomic({
+  repositoryRoot,
+  relativePath: artifactPath,
+  inputPaths: [policyInput.relativePath, summaryInput.relativePath],
+  value: {
+    schemaVersion: 2,
+    policy: policyInput.relativePath,
+    summary: summaryInput.relativePath,
+    ...result,
+  },
 });
-const artifact = {
-  schemaVersion: 2,
-  policy: policyPath,
-  summary: summaryPath,
-  changedFiles: changedFilesPath ?? null,
-  ...result,
-};
-const resolvedArtifactPath = path.resolve(repositoryRoot, artifactPath);
-await mkdir(path.dirname(resolvedArtifactPath), { recursive: true });
-await writeFile(resolvedArtifactPath, `${JSON.stringify(artifact, null, 2)}\n`);
 
 if (result.failures.length > 0) {
-  process.stderr.write(
-    `Risk coverage failed:\n- ${result.failures.join("\n- ")}\n`,
-  );
+  process.stderr.write(`Risk coverage failed:\n- ${result.failures.join("\n- ")}\n`);
   process.exit(1);
 }
 process.stdout.write(

scripts/lib/risk-coverage-files.ts

@@ -0,0 +1,249 @@
+import { randomUUID } from "node:crypto";
+import { constants, type Stats } from "node:fs";
+import {
+  lstat,
+  mkdir,
+  open,
+  realpath,
+  rename,
+  rm,
+} from "node:fs/promises";
+import path from "node:path";
+
+import { normalizeRepositoryRelativePath } from "./repository-file-inventory.ts";
+
+type WritableHandle = Readonly<{
+  writeFile(data: string): Promise<unknown>;
+  sync(): Promise<unknown>;
+  close(): Promise<unknown>;
+}>;
+
+type DirectoryHandle = Readonly<{
+  sync(): Promise<unknown>;
+  close(): Promise<unknown>;
+}>;
+
+export type RiskCoverageArtifactFileSystem = Readonly<{
+  openFile(target: string, flags: number, mode: number): Promise<WritableHandle>;
+  openDirectory(target: string): Promise<DirectoryHandle>;
+  rename(source: string, destination: string): Promise<unknown>;
+  rm(target: string, options: Readonly<{ force: true }>): Promise<unknown>;
+}>;
+
+type WriterDependencies = Readonly<{
+  createNonce?: () => string;
+  fileSystem?: RiskCoverageArtifactFileSystem;
+}>;
+
+const defaultFileSystem: RiskCoverageArtifactFileSystem = Object.freeze({
+  openFile: async (target, flags, mode) => {
+    const handle = await open(target, flags, mode);
+    return {
+      writeFile: async (data) => handle.writeFile(data, "utf8"),
+      sync: async () => handle.sync(),
+      close: async () => handle.close(),
+    };
+  },
+  openDirectory: async (target) => {
+    const handle = await open(target, constants.O_RDONLY);
+    return {
+      sync: async () => handle.sync(),
+      close: async () => handle.close(),
+    };
+  },
+  rename,
+  rm,
+});
+
+function hasErrorCode(error: unknown, code: string): boolean {
+  return (
+    typeof error === "object" &&
+    error !== null &&
+    "code" in error &&
+    error.code === code
+  );
+}
+
+function isWithin(root: string, target: string): boolean {
+  const relative = path.relative(root, target);
+  return (
+    relative === "" ||
+    (relative !== ".." &&
+      !relative.startsWith(`..${path.sep}`) &&
+      !path.isAbsolute(relative))
+  );
+}
+
+function assertDirectory(metadata: Stats, relativePath: string): void {
+  if (metadata.isSymbolicLink()) {
+    throw new TypeError(`artifact ancestor is a symlink: ${relativePath}`);
+  }
+  if (!metadata.isDirectory()) {
+    throw new TypeError(`artifact ancestor is not a directory: ${relativePath}`);
+  }
+}
+
+export async function readRiskCoverageInput(input: Readonly<{
+  repositoryRoot: string;
+  relativePath: string;
+  label: string;
+}>): Promise<Readonly<{ relativePath: string; absolutePath: string; text: string }>> {
+  const relativePath = normalizeRepositoryRelativePath(
+    input.relativePath,
+    `${input.label} path`,
+  );
+  const repositoryRoot = path.resolve(input.repositoryRoot);
+  const repositoryRealpath = await realpath(repositoryRoot);
+  const absolutePath = path.resolve(repositoryRoot, relativePath);
+  const metadata = await lstat(absolutePath);
+  if (metadata.isSymbolicLink()) {
+    throw new TypeError(`${input.label} path is a symlink: ${relativePath}`);
+  }
+  if (!metadata.isFile()) {
+    throw new TypeError(`${input.label} path is not a regular file: ${relativePath}`);
+  }
+  const resolvedPath = await realpath(absolutePath);
+  if (!isWithin(repositoryRealpath, resolvedPath)) {
+    throw new TypeError(`${input.label} path is outside repository: ${relativePath}`);
+  }
+
+  const handle = await open(
+    absolutePath,
+    constants.O_RDONLY | constants.O_NOFOLLOW,
+  );
+  try {
+    const openedMetadata = await handle.stat();
+    if (!openedMetadata.isFile()) {
+      throw new TypeError(`${input.label} path is not a regular file: ${relativePath}`);
+    }
+    const text = await handle.readFile("utf8");
+    return Object.freeze({ relativePath, absolutePath, text });
+  } finally {
+    await handle.close();
+  }
+}
+
+export async function resolveRiskCoverageArtifactPath(input: Readonly<{
+  repositoryRoot: string;
+  relativePath: string;
+  inputPaths: readonly string[];
+}>): Promise<string> {
+  const relativePath = normalizeRepositoryRelativePath(
+    input.relativePath,
+    "artifact path",
+  );
+  if (!relativePath.startsWith("artifacts/quality/")) {
+    throw new TypeError("artifact path must be below artifacts/quality");
+  }
+  const normalizedInputs = input.inputPaths.map((inputPath) =>
+    normalizeRepositoryRelativePath(inputPath, "input path"),
+  );
+  if (normalizedInputs.includes(relativePath)) {
+    throw new TypeError(`artifact path must not overwrite an input: ${relativePath}`);
+  }
+
+  const repositoryRoot = path.resolve(input.repositoryRoot);
+  const repositoryRealpath = await realpath(repositoryRoot);
+  const relativeDirectory = path.posix.dirname(relativePath);
+  let currentDirectory = repositoryRoot;
+  let currentRelative = "";
+  for (const segment of relativeDirectory.split("/")) {
+    currentDirectory = path.join(currentDirectory, segment);
+    currentRelative = currentRelative ? `${currentRelative}/${segment}` : segment;
+    let metadata: Stats;
+    try {
+      metadata = await lstat(currentDirectory);
+    } catch (error) {
+      if (!hasErrorCode(error, "ENOENT")) throw error;
+      try {
+        await mkdir(currentDirectory);
+      } catch (mkdirError) {
+        if (!hasErrorCode(mkdirError, "EEXIST")) throw mkdirError;
+      }
+      metadata = await lstat(currentDirectory);
+    }
+    assertDirectory(metadata, currentRelative);
+    const resolvedDirectory = await realpath(currentDirectory);
+    if (!isWithin(repositoryRealpath, resolvedDirectory)) {
+      throw new TypeError(`artifact ancestor is outside repository: ${currentRelative}`);
+    }
+  }
+
+  const absolutePath = path.resolve(repositoryRoot, relativePath);
+  try {
+    const metadata = await lstat(absolutePath);
+    if (metadata.isSymbolicLink()) {
+      throw new TypeError(`artifact path is a symlink: ${relativePath}`);
+    }
+    if (!metadata.isFile()) {
+      throw new TypeError(`artifact path is not a regular file: ${relativePath}`);
+    }
+  } catch (error) {
+    if (!hasErrorCode(error, "ENOENT")) throw error;
+  }
+  return absolutePath;
+}
+
+export async function writeRiskCoverageArtifactAtomic(
+  input: Readonly<{
+    repositoryRoot: string;
+    relativePath: string;
+    inputPaths: readonly string[];
+    value: unknown;
+  }>,
+  dependencies: WriterDependencies = {},
+): Promise<void> {
+  const serialized = JSON.stringify(input.value, null, 2);
+  if (serialized === undefined) {
+    throw new TypeError("risk coverage artifact is not JSON serializable");
+  }
+  const destination = await resolveRiskCoverageArtifactPath(input);
+  const temporaryPath = path.join(
+    path.dirname(destination),
+    `.${path.basename(destination)}.${(dependencies.createNonce ?? randomUUID)()}.tmp`,
+  );
+  const fileSystem = dependencies.fileSystem ?? defaultFileSystem;
+  let ownsTemporaryFile = false;
+  try {
+    const handle = await fileSystem.openFile(
+      temporaryPath,
+      constants.O_WRONLY |
+        constants.O_CREAT |
+        constants.O_EXCL |
+        constants.O_NOFOLLOW,
+      0o600,
+    );
+    ownsTemporaryFile = true;
+    let primaryFailure: unknown;
+    try {
+      await handle.writeFile(`${serialized}\n`);
+      await handle.sync();
+    } catch (error) {
+      primaryFailure = error;
+    }
+    try {
+      await handle.close();
+    } catch (error) {
+      primaryFailure ??= error;
+    }
+    if (primaryFailure !== undefined) throw primaryFailure;
+
+    await fileSystem.rename(temporaryPath, destination);
+    ownsTemporaryFile = false;
+    const directoryHandle = await fileSystem.openDirectory(path.dirname(destination));
+    try {
+      await directoryHandle.sync();
+    } finally {
+      await directoryHandle.close();
+    }
+  } catch (error) {
+    if (ownsTemporaryFile) {
+      try {
+        await fileSystem.rm(temporaryPath, { force: true });
+      } catch {
+        // Preserve the publication failure and clean only our nonce-owned path.
+      }
+    }
+    throw error;
+  }
+}

scripts/lib/risk-coverage.ts

@@ -1,5 +1,11 @@
-import { open, readdir, realpath, lstat } from "node:fs/promises";
-import type { Dirent, Stats } from "node:fs";
+import { constants, type Dirent, type Stats } from "node:fs";
+import {
+  lstat,
+  open,
+  readdir,
+  realpath,
+  type FileHandle,
+} from "node:fs/promises";
 import path from "node:path";
 
 import { normalizeRepositoryRelativePath } from "./repository-file-inventory.ts";
@@ -10,6 +16,8 @@ const coverageMetrics = [
   "functions",
   "branches",
 ] as const;
+const teamIdPattern = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/u;
+const maximumWaiverDurationMs = 90 * 24 * 60 * 60 * 1_000;
 
 export const REQUIRED_HIGH_RISK_PATHS = Object.freeze([
   "src/adapters/http/http-execution-v3.ts",
@@ -23,10 +31,14 @@ export const REQUIRED_HIGH_RISK_PATHS = Object.freeze([
 ] as const);
 
 type CoverageMetric = (typeof coverageMetrics)[number];
-type Thresholds = Readonly<Partial<Record<CoverageMetric, number>>>;
-type CoverageMetrics = Readonly<
-  Record<CoverageMetric, Readonly<{ pct: number }>>
->;
+type Thresholds = Readonly<Record<CoverageMetric, number>>;
+type CoverageCounter = Readonly<{
+  total: number;
+  covered: number;
+  skipped: number;
+  pct: number;
+}>;
+type CoverageMetrics = Readonly<Record<CoverageMetric, CoverageCounter>>;
 
 export type RiskCoveragePolicy = Readonly<{
   schemaVersion: 2;
@@ -47,12 +59,23 @@ export type RiskCoveragePolicy = Readonly<{
   }>[];
 }>;
 
+export type ProductionModuleInventory = Readonly<{
+  files: readonly string[];
+  preExclusionTotal: number;
+  generatedExclusions: readonly string[];
+}>;
+
 export type RiskCoverageResult = Readonly<{
   status: "PASS" | "FAIL";
   selectedTotal: number;
   repositoryTotal: number;
+  preExclusionTotal: number;
+  generatedExclusionCount: number;
+  generatedExclusions: readonly string[];
+  ownershipScope: "ALL_POLICY_HIGH_RISK";
+  ownedHighRiskPaths: readonly string[];
+  waivedHighRiskPaths: readonly string[];
   uncoveredModules: readonly string[];
-  ignoredCoveragePaths: readonly string[];
   results: readonly Readonly<{
     scope: string;
     metric: CoverageMetric;
@@ -63,13 +86,14 @@ export type RiskCoverageResult = Readonly<{
   failures: readonly string[];
 }>;
 
+type ReadableFileHandle = Pick<FileHandle, "close" | "stat">;
 type InventoryOptions = Readonly<{
   repositoryRoot?: string;
   generatedPaths?: readonly string[];
   readDirectory?: (target: string) => Promise<Dirent[]>;
   lstatPath?: (target: string) => Promise<Stats>;
   realpathPath?: (target: string) => Promise<string>;
-  assertReadable?: (target: string) => Promise<void>;
+  openFile?: (target: string, flags: number) => Promise<ReadableFileHandle>;
 }>;
 
 function isRecord(value: unknown): value is Record<string, unknown> {
@@ -90,9 +114,7 @@ function assertExactKeys(
 function exactSourcePath(value: unknown, label: string): string {
   if (
     typeof value !== "string" ||
-    ["*", "?", "[", "]", "{", "}"].some((character) =>
-      value.includes(character),
-    )
+    ["*", "?", "[", "]", "{", "}"].some((character) => value.includes(character))
   ) {
     throw new TypeError(`${label} must be an exact repository-relative POSIX path`);
   }
@@ -103,20 +125,15 @@ function exactSourcePath(value: unknown, label: string): string {
   return normalized;
 }
 
-function nonBlank(value: unknown, label: string): string {
-  if (typeof value !== "string" || !value.trim()) {
-    throw new TypeError(`${label} must be a nonblank string`);
-  }
-  return value.trim();
-}
-
 function uniquePaths(
   value: unknown,
   label: string,
   options: Readonly<{ allowEmpty: boolean }> = { allowEmpty: true },
 ): readonly string[] {
   if (!Array.isArray(value) || (!options.allowEmpty && value.length === 0)) {
-    throw new TypeError(`${label} must be an array${options.allowEmpty ? "" : " with at least one path"}`);
+    throw new TypeError(
+      `${label} must be an array${options.allowEmpty ? "" : " with at least one path"}`,
+    );
   }
   const paths = value.map((entry) => exactSourcePath(entry, `${label} entry`));
   if (new Set(paths).size !== paths.length) {
@@ -125,43 +142,60 @@ function uniquePaths(
   return Object.freeze(paths);
 }
 
-function thresholds(
-  value: unknown,
-  label: string,
-  options: Readonly<{ requireAll: boolean }>,
-): Thresholds {
-  if (!isRecord(value)) {
-    throw new TypeError(`${label} must be an object`);
+function teamId(value: unknown, label: string): string {
+  if (typeof value !== "string" || !teamIdPattern.test(value)) {
+    throw new TypeError(`${label} must be a canonical team id`);
   }
+  return value;
+}
+
+function thresholds(value: unknown, label: string): Thresholds {
+  if (!isRecord(value)) throw new TypeError(`${label} must be an object`);
   assertExactKeys(value, coverageMetrics, label);
-  if (
-    Object.keys(value).length === 0 ||
-    (options.requireAll && coverageMetrics.some((metric) => !(metric in value)))
-  ) {
-    throw new TypeError(`${label} must define ${options.requireAll ? "all " : "at least one "}coverage metric`);
+  if (coverageMetrics.some((metric) => !(metric in value))) {
+    throw new TypeError(`${label} must define all coverage metrics`);
   }
-  const parsed: Partial<Record<CoverageMetric, number>> = {};
-  for (const [metric, threshold] of Object.entries(value)) {
+  const parsed = {} as Record<CoverageMetric, number>;
+  for (const metric of coverageMetrics) {
+    const threshold = value[metric];
     if (
       typeof threshold !== "number" ||
       !Number.isFinite(threshold) ||
-      threshold < 0 ||
+      threshold <= 0 ||
       threshold > 100
     ) {
-      throw new TypeError(`${label}.${metric} minimum must be a finite number from 0 to 100`);
+      throw new TypeError(
+        `${label}.${metric} minimum must be a finite number greater than 0 and at most 100`,
+      );
     }
-    parsed[metric as CoverageMetric] = threshold;
+    parsed[metric] = threshold;
   }
   return Object.freeze(parsed);
 }
 
+function waiverReason(value: unknown, label: string): string {
+  if (typeof value !== "string" || value.length < 12 || value.length > 240) {
+    throw new TypeError(`${label} must contain 12 to 240 characters`);
+  }
+  if (value !== value.trim()) {
+    throw new TypeError(`${label} must not contain surrounding whitespace`);
+  }
+  if (
+    [...value].some((character) => {
+      const codePoint = character.codePointAt(0) ?? 0;
+      return codePoint <= 31 || codePoint === 127;
+    })
+  ) {
+    throw new TypeError(`${label} must not contain control characters`);
+  }
+  return value;
+}
+
 export function parseRiskCoveragePolicy(
   value: unknown,
   options: Readonly<{ now?: number }> = {},
 ): RiskCoveragePolicy {
-  if (!isRecord(value)) {
-    throw new TypeError("risk coverage policy must be an object");
-  }
+  if (!isRecord(value)) throw new TypeError("risk coverage policy must be an object");
   assertExactKeys(
     value,
     [
@@ -180,11 +214,12 @@ export function parseRiskCoveragePolicy(
   }
   if (
     typeof value.repositoryBaseline !== "number" ||
-    !Number.isInteger(value.repositoryBaseline) ||
+    !Number.isSafeInteger(value.repositoryBaseline) ||
     value.repositoryBaseline <= 0
   ) {
-    throw new TypeError("repositoryBaseline must be a positive integer");
+    throw new TypeError("repositoryBaseline must be a positive safe integer");
   }
+
   const generatedPaths = uniquePaths(value.generatedPaths, "generatedPaths");
   const highRiskPaths = uniquePaths(value.highRiskPaths, "highRiskPaths", {
     allowEmpty: false,
@@ -199,48 +234,65 @@ export function parseRiskCoveragePolicy(
     assertExactKeys(candidate, ["path", "owner", "minimum"], `criticalModules[${index}]`);
     return Object.freeze({
       path: exactSourcePath(candidate.path, `criticalModules[${index}].path`),
-      owner: nonBlank(candidate.owner, `criticalModules[${index}].owner`),
-      minimum: thresholds(candidate.minimum, `criticalModules[${index}].minimum`, {
-        requireAll: false,
-      }),
+      owner: teamId(candidate.owner, `criticalModules[${index}].owner`),
+      minimum: thresholds(candidate.minimum, `criticalModules[${index}].minimum`),
     });
   });
   if (new Set(criticalModules.map((entry) => entry.path)).size !== criticalModules.length) {
     throw new TypeError("criticalModules contains a duplicate path");
   }
-  if (!Array.isArray(value.waivers)) {
-    throw new TypeError("waivers must be an array");
-  }
+
+  if (!Array.isArray(value.waivers)) throw new TypeError("waivers must be an array");
   const currentTime = options.now ?? Date.now();
+  if (!Number.isFinite(currentTime)) throw new TypeError("policy time must be finite");
   const waivers = value.waivers.map((candidate, index) => {
-    if (!isRecord(candidate)) {
-      throw new TypeError(`waivers[${index}] must be an object`);
-    }
+    if (!isRecord(candidate)) throw new TypeError(`waivers[${index}] must be an object`);
     assertExactKeys(candidate, ["path", "owner", "reason", "expiresAt"], `waivers[${index}]`);
     const waiverPath = exactSourcePath(candidate.path, `waivers[${index}].path`);
-    const expiresAt = nonBlank(candidate.expiresAt, `waivers[${index}].expiresAt`);
+    const expiresAt = candidate.expiresAt;
+    if (typeof expiresAt !== "string") {
+      throw new TypeError(`waivers[${index}].expiresAt must be a canonical UTC ISO timestamp`);
+    }
     const expiry = Date.parse(expiresAt);
-    if (!Number.isFinite(expiry) || expiry <= currentTime) {
-      throw new TypeError(`waivers[${index}] is expired or has an invalid expiry`);
+    if (!Number.isFinite(expiry) || new Date(expiry).toISOString() !== expiresAt) {
+      throw new TypeError(`waivers[${index}].expiresAt must be a canonical UTC ISO timestamp`);
+    }
+    if (expiry <= currentTime) throw new TypeError(`waivers[${index}] is expired`);
+    if (expiry - currentTime > maximumWaiverDurationMs) {
+      throw new TypeError(`waivers[${index}] expiry must be within 90 days`);
     }
     if (!highRiskPaths.includes(waiverPath)) {
       throw new TypeError(`waivers[${index}] is stale because ${waiverPath} is not high-risk`);
     }
     return Object.freeze({
       path: waiverPath,
-      owner: nonBlank(candidate.owner, `waivers[${index}].owner`),
-      reason: nonBlank(candidate.reason, `waivers[${index}].reason`),
+      owner: teamId(candidate.owner, `waivers[${index}].owner`),
+      reason: waiverReason(candidate.reason, `waivers[${index}].reason`),
       expiresAt,
     });
   });
   if (new Set(waivers.map((entry) => entry.path)).size !== waivers.length) {
     throw new TypeError("waivers contains a duplicate path");
   }
+
+  const criticalPaths = new Set(criticalModules.map((entry) => entry.path));
+  const waiverPaths = new Set(waivers.map((entry) => entry.path));
+  for (const highRiskPath of highRiskPaths) {
+    if (criticalPaths.has(highRiskPath) && waiverPaths.has(highRiskPath)) {
+      throw new TypeError(
+        `high-risk module cannot have both a critical owner and waiver: ${highRiskPath}`,
+      );
+    }
+    if (!criticalPaths.has(highRiskPath) && !waiverPaths.has(highRiskPath)) {
+      throw new TypeError(`high-risk module has no owner or waiver: ${highRiskPath}`);
+    }
+  }
+
   return Object.freeze({
     schemaVersion: 2,
     repositoryBaseline: value.repositoryBaseline,
     generatedPaths,
-    summary: thresholds(value.summary, "summary", { requireAll: true }),
+    summary: thresholds(value.summary, "summary"),
     criticalModules: Object.freeze(criticalModules),
     highRiskPaths,
     waivers: Object.freeze(waivers),
@@ -256,15 +308,15 @@ export function parseRepositoryRiskCoveragePolicy(
     if (!policy.highRiskPaths.includes(requiredPath)) {
       throw new TypeError(`required high-risk path is missing: ${requiredPath}`);
     }
+    if (policy.generatedPaths.includes(requiredPath)) {
+      throw new TypeError(
+        `required high-risk path cannot be generated-excluded: ${requiredPath}`,
+      );
+    }
   }
   return policy;
 }
 
-async function defaultAssertReadable(target: string): Promise<void> {
-  const handle = await open(target, "r");
-  await handle.close();
-}
-
 function isWithin(root: string, target: string): boolean {
   const relative = path.relative(root, target);
   return (
@@ -275,7 +327,7 @@ function isWithin(root: string, target: string): boolean {
   );
 }
 
-function isProductionModule(relativePath: string): boolean {
+export function isProductionModulePath(relativePath: string): boolean {
   return (
     /\.tsx?$/u.test(relativePath) &&
     !/\.d\.ts$/u.test(relativePath) &&
@@ -285,13 +337,15 @@ function isProductionModule(relativePath: string): boolean {
 
 export async function buildProductionModuleInventory(
   options: InventoryOptions = {},
-): Promise<readonly string[]> {
+): Promise<ProductionModuleInventory> {
   const repositoryRoot = path.resolve(options.repositoryRoot ?? process.cwd());
   const sourceRoot = path.join(repositoryRoot, "src");
-  const readDirectory = options.readDirectory ?? ((target) => readdir(target, { withFileTypes: true }));
+  const readDirectory = options.readDirectory ??
+    ((target: string) => readdir(target, { withFileTypes: true }));
   const lstatPath = options.lstatPath ?? lstat;
   const realpathPath = options.realpathPath ?? realpath;
-  const assertReadable = options.assertReadable ?? defaultAssertReadable;
+  const openFile = options.openFile ??
+    ((target: string, flags: number) => open(target, flags));
   const generatedPaths = uniquePaths(options.generatedPaths ?? [], "generatedPaths");
   const generated = new Set(generatedPaths);
   const repositoryRealpath = await realpathPath(repositoryRoot);
@@ -322,7 +376,7 @@ export async function buildProductionModuleInventory(
         await visit(relativeTarget);
         continue;
       }
-      if (!isProductionModule(relativeTarget)) continue;
+      if (!isProductionModulePath(relativeTarget)) continue;
       if (!metadata.isFile()) {
         throw new TypeError(`production inventory path is not a regular file: ${relativeTarget}`);
       }
@@ -330,12 +384,22 @@ export async function buildProductionModuleInventory(
       if (!isWithin(repositoryRealpath, resolvedTarget)) {
         throw new TypeError(`production inventory path is outside repository: ${relativeTarget}`);
       }
+      let handle: ReadableFileHandle | undefined;
       try {
-        await assertReadable(absoluteTarget);
+        handle = await openFile(
+          absoluteTarget,
+          constants.O_RDONLY | constants.O_NOFOLLOW,
+        );
+        const openedMetadata = await handle.stat();
+        if (!openedMetadata.isFile()) {
+          throw new TypeError("opened target is not a regular file");
+        }
       } catch (error) {
         throw new Error(`production inventory file is unreadable: ${relativeTarget}`, {
           cause: error,
         });
+      } finally {
+        await handle?.close();
       }
       allModules.push(relativeTarget);
     }
@@ -347,35 +411,89 @@ export async function buildProductionModuleInventory(
     }
   }
   const inventory = allModules.filter((file) => !generated.has(file)).sort();
-  if (inventory.length === 0) {
-    throw new Error("production module inventory is empty");
-  }
+  if (inventory.length === 0) throw new Error("production module inventory is empty");
   if (new Set(inventory).size !== inventory.length) {
     throw new TypeError("production module inventory contains a duplicate path");
   }
-  return Object.freeze(inventory);
+  return Object.freeze({
+    files: Object.freeze(inventory),
+    preExclusionTotal: allModules.length,
+    generatedExclusions: Object.freeze([...generatedPaths].sort()),
+  });
 }
 
-function coveragePath(repositoryRoot: string, rawPath: string): string {
-  if (rawPath.includes("\\") || rawPath.includes("\0")) {
+export function normalizeCoverageProducerPath(input: Readonly<{
+  repositoryRoot: string;
+  rawPath: string;
+  platform?: "posix" | "win32";
+}>): string {
+  const platform = input.platform ?? (process.platform === "win32" ? "win32" : "posix");
+  const pathApi = platform === "win32" ? path.win32 : path.posix;
+  const { rawPath } = input;
+  if (rawPath.includes("\0")) throw new TypeError("coverage path contains NUL");
+  if (platform === "posix" && rawPath.includes("\\")) {
     throw new TypeError("coverage path must use POSIX separators");
   }
-  if (path.isAbsolute(rawPath)) {
-    const relative = path.relative(repositoryRoot, rawPath).split(path.sep).join("/");
-    if (!relative || relative === ".." || relative.startsWith("../")) {
+  if (platform === "win32" && rawPath.includes("\\") && !pathApi.isAbsolute(rawPath)) {
+    throw new TypeError("relative coverage path must use POSIX separators");
+  }
+  if (pathApi.isAbsolute(rawPath)) {
+    const root = pathApi.resolve(input.repositoryRoot);
+    const relative = pathApi.relative(root, pathApi.resolve(rawPath));
+    if (
+      !relative ||
+      relative === ".." ||
+      relative.startsWith(`..${pathApi.sep}`) ||
+      pathApi.isAbsolute(relative)
+    ) {
       throw new TypeError(`coverage path is outside repository: ${rawPath}`);
     }
-    return normalizeRepositoryRelativePath(relative, "coverage path");
+    return normalizeRepositoryRelativePath(
+      relative.split(pathApi.sep).join("/"),
+      "coverage path",
+    );
   }
   return normalizeRepositoryRelativePath(rawPath, "coverage path");
 }
 
+function expectedPct(total: number, covered: number): number {
+  return total === 0 ? 100 : Math.floor((covered / total) * 10_000) / 100;
+}
+
+function parseCoverageCounter(value: unknown, label: string): CoverageCounter {
+  if (!isRecord(value)) throw new TypeError(`${label} must be an object`);
+  const fields = ["total", "covered", "skipped", "pct"] as const;
+  assertExactKeys(value, fields, label);
+  if (fields.some((field) => !(field in value))) {
+    throw new TypeError(`${label} must define total, covered, skipped, and pct`);
+  }
+  for (const count of ["total", "covered", "skipped"] as const) {
+    if (
+      typeof value[count] !== "number" ||
+      !Number.isSafeInteger(value[count]) ||
+      value[count] < 0
+    ) {
+      throw new TypeError(`${label}.${count} must be a nonnegative safe integer`);
+    }
+  }
+  const total = value.total as number;
+  const covered = value.covered as number;
+  const skipped = value.skipped as number;
+  if (covered + skipped > total) {
+    throw new TypeError(`${label} covered plus skipped must not exceed total`);
+  }
+  const pct = value.pct;
+  const calculatedPct = expectedPct(total, covered);
+  if (typeof pct !== "number" || !Number.isFinite(pct) || pct !== calculatedPct) {
+    throw new TypeError(`${label}.pct must equal ${calculatedPct}`);
+  }
+  return Object.freeze({ total, covered, skipped, pct });
+}
+
 function parseCoverageMetrics(value: unknown, label: string): CoverageMetrics {
   if (!isRecord(value)) throw new TypeError(`${label} must be an object`);
   const unknownMetrics = Object.keys(value).filter(
-    (metric) =>
-      metric !== "branchesTrue" &&
-      !coverageMetrics.includes(metric as CoverageMetric),
+    (metric) => metric !== "branchesTrue" && !coverageMetrics.includes(metric as CoverageMetric),
   );
   if (unknownMetrics.length > 0) {
     throw new TypeError(
@@ -383,104 +501,85 @@ function parseCoverageMetrics(value: unknown, label: string): CoverageMetrics {
     );
   }
   if (value.branchesTrue !== undefined) {
-    if (!isRecord(value.branchesTrue)) {
-      throw new TypeError(`${label}.branchesTrue must be an object`);
-    }
-    assertExactKeys(
-      value.branchesTrue,
-      ["total", "covered", "skipped", "pct"],
-      `${label}.branchesTrue`,
-    );
-    for (const count of ["total", "covered", "skipped"] as const) {
-      const received = value.branchesTrue[count];
-      if (
-        typeof received !== "number" ||
-        !Number.isSafeInteger(received) ||
-        received < 0
-      ) {
-        throw new TypeError(
-          `${label}.branchesTrue.${count} must be a nonnegative safe integer`,
-        );
-      }
-    }
-    const pct = value.branchesTrue.pct;
-    if (typeof pct !== "number" || !Number.isFinite(pct) || pct < 0 || pct > 100) {
-      throw new TypeError(
-        `${label}.branchesTrue.pct must be a finite number from 0 to 100`,
-      );
-    }
-    if (
-      (value.branchesTrue.covered as number) >
-        (value.branchesTrue.total as number) ||
-      (value.branchesTrue.skipped as number) >
-        (value.branchesTrue.total as number)
-    ) {
-      throw new TypeError(`${label}.branchesTrue counts exceed total`);
-    }
+    parseCoverageCounter(value.branchesTrue, `${label}.branchesTrue`);
   }
-  const parsed = {} as Record<CoverageMetric, { pct: number }>;
+  const parsed = {} as Record<CoverageMetric, CoverageCounter>;
   for (const metric of coverageMetrics) {
-    const rawMetric = value[metric];
-    if (!isRecord(rawMetric)) {
-      throw new TypeError(`${label}.${metric} must be an object`);
-    }
-    assertExactKeys(
-      rawMetric,
-      ["total", "covered", "skipped", "pct"],
-      `${label}.${metric}`,
-    );
-    const suppliedCounts = ["total", "covered", "skipped"].filter(
-      (count) => rawMetric[count] !== undefined,
-    );
-    if (suppliedCounts.length !== 0 && suppliedCounts.length !== 3) {
-      throw new TypeError(
-        `${label}.${metric} must define total, covered, and skipped together`,
-      );
-    }
-    for (const count of suppliedCounts) {
-      const received = rawMetric[count];
-      if (
-        typeof received !== "number" ||
-        !Number.isSafeInteger(received) ||
-        received < 0
-      ) {
-        throw new TypeError(
-          `${label}.${metric}.${count} must be a nonnegative safe integer`,
-        );
-      }
-    }
-    if (
-      suppliedCounts.length === 3 &&
-      ((rawMetric.covered as number) > (rawMetric.total as number) ||
-        (rawMetric.skipped as number) > (rawMetric.total as number))
-    ) {
-      throw new TypeError(`${label}.${metric} counts exceed total`);
-    }
-    const pct = rawMetric.pct;
-    if (typeof pct !== "number" || !Number.isFinite(pct) || pct < 0 || pct > 100) {
-      throw new TypeError(`${label}.${metric}.pct must be a finite number from 0 to 100`);
-    }
-    parsed[metric] = { pct };
+    parsed[metric] = parseCoverageCounter(value[metric], `${label}.${metric}`);
   }
   return Object.freeze(parsed);
 }
 
+function aggregateCoverage(selected: readonly CoverageMetrics[]): CoverageMetrics {
+  const aggregate = {} as Record<CoverageMetric, CoverageCounter>;
+  for (const metric of coverageMetrics) {
+    let total = 0;
+    let covered = 0;
+    let skipped = 0;
+    for (const metrics of selected) {
+      total += metrics[metric].total;
+      covered += metrics[metric].covered;
+      skipped += metrics[metric].skipped;
+      if (![total, covered, skipped].every(Number.isSafeInteger)) {
+        throw new TypeError(`recomputed coverage ${metric} count exceeds safe integer range`);
+      }
+    }
+    aggregate[metric] = Object.freeze({
+      total,
+      covered,
+      skipped,
+      pct: expectedPct(total, covered),
+    });
+  }
+  return Object.freeze(aggregate);
+}
+
+function assertMatchingTotal(
+  producer: CoverageMetrics,
+  recomputed: CoverageMetrics,
+): void {
+  for (const metric of coverageMetrics) {
+    const actual = producer[metric];
+    const expected = recomputed[metric];
+    if (
+      actual.total !== expected.total ||
+      actual.covered !== expected.covered ||
+      actual.skipped !== expected.skipped ||
+      actual.pct !== expected.pct
+    ) {
+      throw new TypeError(
+        `coverage total.${metric} does not match recomputed inventory total`,
+      );
+    }
+  }
+}
+
 export function evaluateRiskCoverage(input: Readonly<{
   repositoryRoot?: string;
-  inventory: readonly string[];
+  inventory: ProductionModuleInventory;
   policy: RiskCoveragePolicy;
   summary: unknown;
-  changedFiles?: readonly string[];
-  now?: number;
 }>): RiskCoverageResult {
   const repositoryRoot = path.resolve(input.repositoryRoot ?? process.cwd());
-  if (input.inventory.length === 0) {
-    throw new TypeError("production module inventory is empty");
-  }
-  const inventory = input.inventory.map((file) => exactSourcePath(file, "inventory path"));
+  const inventory = input.inventory.files.map((file) => exactSourcePath(file, "inventory path"));
+  if (inventory.length === 0) throw new TypeError("production module inventory is empty");
   if (new Set(inventory).size !== inventory.length) {
     throw new TypeError("production module inventory contains a duplicate path");
   }
+  const generatedExclusions = input.inventory.generatedExclusions.map((file) =>
+    exactSourcePath(file, "generated exclusion"),
+  );
+  if (
+    new Set(generatedExclusions).size !== generatedExclusions.length ||
+    input.inventory.preExclusionTotal !== inventory.length + generatedExclusions.length ||
+    !Number.isSafeInteger(input.inventory.preExclusionTotal)
+  ) {
+    throw new TypeError("production inventory provenance is inconsistent");
+  }
+  const policyGenerated = [...input.policy.generatedPaths].sort();
+  if (generatedExclusions.join("\n") !== policyGenerated.join("\n")) {
+    throw new TypeError("production inventory generated exclusions do not match policy");
+  }
   if (!isRecord(input.summary) || !("total" in input.summary)) {
     throw new TypeError("coverage summary must contain total metrics");
   }
@@ -488,13 +587,25 @@ export function evaluateRiskCoverage(input: Readonly<{
   const selected = new Map<string, CoverageMetrics>();
   for (const [rawPath, rawMetrics] of Object.entries(input.summary)) {
     if (rawPath === "total") continue;
-    const normalized = coveragePath(repositoryRoot, rawPath);
-    if (selected.has(normalized)) {
-      throw new TypeError(`duplicate coverage path: ${normalized}`);
-    }
+    const normalized = normalizeCoverageProducerPath({ repositoryRoot, rawPath });
+    if (selected.has(normalized)) throw new TypeError(`duplicate coverage path: ${normalized}`);
     selected.set(normalized, parseCoverageMetrics(rawMetrics, `coverage ${normalized}`));
   }
 
+  const inventorySet = new Set(inventory);
+  const generatedSet = new Set(generatedExclusions);
+  for (const selectedPath of selected.keys()) {
+    if (!inventorySet.has(selectedPath) && !generatedSet.has(selectedPath)) {
+      throw new TypeError(`unexpected coverage path outside inventory: ${selectedPath}`);
+    }
+  }
+  const inventoryMetrics = inventory.flatMap((file) => {
+    const metrics = selected.get(file);
+    return metrics ? [metrics] : [];
+  });
+  assertMatchingTotal(totalMetrics, aggregateCoverage([...selected.values()]));
+  const recomputedInventoryMetrics = aggregateCoverage(inventoryMetrics);
+
   const failures: string[] = [];
   const results: Array<{
     scope: string;
@@ -506,30 +617,21 @@ export function evaluateRiskCoverage(input: Readonly<{
   function evaluate(scope: string, actual: CoverageMetrics, minimum: Thresholds): void {
     for (const metric of coverageMetrics) {
       const threshold = minimum[metric];
-      if (threshold === undefined) continue;
       const received = actual[metric].pct;
       const passed = received >= threshold;
       results.push({ scope, metric, threshold, received, passed });
-      if (!passed) {
-        failures.push(`${scope}.${metric} expected >= ${threshold}, received ${received}`);
-      }
+      if (!passed) failures.push(`${scope}.${metric} expected >= ${threshold}, received ${received}`);
     }
   }
-  evaluate("total", totalMetrics, input.policy.summary);
-  const inventorySet = new Set(inventory);
+
+  evaluate("total", recomputedInventoryMetrics, input.policy.summary);
   if (inventory.length < input.policy.repositoryBaseline) {
     failures.push(
       `repository module baseline expected >= ${input.policy.repositoryBaseline}, received ${inventory.length}`,
     );
   }
   const uncoveredModules = inventory.filter((file) => !selected.has(file)).sort();
-  const selectedModules = inventory.filter((file) => selected.has(file));
-  const ignoredCoveragePaths = [...selected.keys()]
-    .filter((file) => !inventorySet.has(file))
-    .sort();
-  failures.push(
-    ...uncoveredModules.map((file) => `production module missing from coverage: ${file}`),
-  );
+  failures.push(...uncoveredModules.map((file) => `production module missing from coverage: ${file}`));
   for (const modulePolicy of input.policy.criticalModules) {
     if (!inventorySet.has(modulePolicy.path)) {
       failures.push(`critical module is outside production inventory: ${modulePolicy.path}`);
@@ -543,36 +645,34 @@ export function evaluateRiskCoverage(input: Readonly<{
     evaluate(modulePolicy.path, actual, modulePolicy.minimum);
   }
 
-  const owners = new Set(input.policy.criticalModules.map((entry) => entry.path));
-  const waivers = new Set(input.policy.waivers.map((entry) => entry.path));
-  const highRisk = new Set(input.policy.highRiskPaths);
+  const criticalPaths = new Set(input.policy.criticalModules.map((entry) => entry.path));
+  const waiverPaths = new Set(input.policy.waivers.map((entry) => entry.path));
   for (const highRiskPath of input.policy.highRiskPaths) {
-    if (!owners.has(highRiskPath) && !waivers.has(highRiskPath)) {
-      failures.push(`high-risk module has no owner or waiver: ${highRiskPath}`);
-    }
-  }
-  for (const changedFile of input.changedFiles ?? []) {
-    const normalized = exactSourcePath(changedFile, "changed file");
-    if (highRisk.has(normalized) && !owners.has(normalized) && !waivers.has(normalized)) {
-      failures.push(`changed high-risk module has no owner or waiver: ${normalized}`);
+    if (!inventorySet.has(highRiskPath)) {
+      failures.push(`high-risk module is outside production inventory: ${highRiskPath}`);
     }
   }
   for (const waiver of input.policy.waivers) {
-    if (!inventorySet.has(waiver.path) || !highRisk.has(waiver.path)) {
-      failures.push(`coverage waiver is stale: ${waiver.path}`);
-    }
-    const expiry = Date.parse(waiver.expiresAt);
-    if (!Number.isFinite(expiry) || expiry <= (input.now ?? Date.now())) {
-      failures.push(`coverage waiver is expired: ${waiver.path}`);
-    }
+    if (!inventorySet.has(waiver.path)) failures.push(`coverage waiver is stale: ${waiver.path}`);
   }
+  const ownedHighRiskPaths = input.policy.highRiskPaths
+    .filter((modulePath) => criticalPaths.has(modulePath))
+    .sort();
+  const waivedHighRiskPaths = input.policy.highRiskPaths
+    .filter((modulePath) => waiverPaths.has(modulePath))
+    .sort();
 
   return Object.freeze({
     status: failures.length === 0 ? "PASS" : "FAIL",
-    selectedTotal: selectedModules.length,
+    selectedTotal: inventory.length - uncoveredModules.length,
     repositoryTotal: inventory.length,
+    preExclusionTotal: input.inventory.preExclusionTotal,
+    generatedExclusionCount: generatedExclusions.length,
+    generatedExclusions: Object.freeze([...generatedExclusions].sort()),
+    ownershipScope: "ALL_POLICY_HIGH_RISK",
+    ownedHighRiskPaths: Object.freeze(ownedHighRiskPaths),
+    waivedHighRiskPaths: Object.freeze(waivedHighRiskPaths),
     uncoveredModules: Object.freeze(uncoveredModules),
-    ignoredCoveragePaths: Object.freeze(ignoredCoveragePaths),
     results: Object.freeze(results),
     failures: Object.freeze(failures),
   });