policy: canonicalize before resolving specifiers

PR-URL: https://github.com/nodejs/node/pull/37863
Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>
Co-authored-by: James M Snell <jasnell@gmail.com>

Reviewed-By: Guy Bedford <guybedford@gmail.com>

12 files changed, 772 insertions, 351 deletions

diff --git a/doc/api/errors.md b/doc/api/errors.md
index fcbe849d03..8a5d3e5daf 100644
--- a/doc/api/errors.md
+++ b/doc/api/errors.md
@@ -1615,6 +1615,13 @@ A policy manifest resource had an invalid value for one of its fields. Update
 the manifest entry to match in order to resolve this error. See the
 documentation for [policy][] manifests for more information.
 
+<a id="ERR_MANIFEST_INVALID_SPECIFIER"></a>
+### `ERR_MANIFEST_INVALID_SPECIFIER`
+
+A policy manifest resource had an invalid value for one of its dependency
+mappings. Update the manifest entry to match to resolve this error. See the
+documentation for [policy][] manifests for more information.
+
 <a id="ERR_MANIFEST_PARSE_POLICY"></a>
 ### `ERR_MANIFEST_PARSE_POLICY`
 
diff --git a/doc/api/policy.md b/doc/api/policy.md
index 6cca07f8ba..01b3eba0a3 100644
--- a/doc/api/policy.md
+++ b/doc/api/policy.md
@@ -57,7 +57,7 @@ by defining an "onerror" field in a policy manifest. The following values are
 available to change the behavior:
 
 * `"exit"`: will exit the process immediately.
-    No cleanup code will be allowed to run.
+  No cleanup code will be allowed to run.
 * `"log"`: will log the error at the site of the failure.
 * `"throw"`: will throw a JS error at the site of the failure. This is the
   default.
@@ -80,9 +80,9 @@ compatible with the browser
 [integrity attribute](https://www.w3.org/TR/SRI/#the-integrity-attribute)
 associated with absolute URLs.
 
-When using `require()` all resources involved in loading are checked for
-integrity if a policy manifest has been specified. If a resource does not match
-the integrity listed in the manifest, an error will be thrown.
+When using `require()` or `import` all resources involved in loading are checked
+for integrity if a policy manifest has been specified. If a resource does not
+match the integrity listed in the manifest, an error will be thrown.
 
 An example policy file that would allow loading a file `checked.js`:
 
@@ -107,7 +107,7 @@ and hash fragment. `./a.js?b` will not be used when attempting to load
 `./a.js` and vice versa.
 
 To generate integrity strings, a script such as
-`printf "sha384-$(cat checked.js | openssl dgst -sha384 -binary | base64)"`
+`node -e 'process.stdout.write("sha256-");process.stdin.pipe(crypto.createHash("sha256").setEncoding("base64")).pipe(process.stdout)' < FILE`
 can be used.
 
 Integrity can be specified as the boolean value `true` to accept any
@@ -140,13 +140,37 @@ The dependencies are keyed by the requested specifier string and have values
 of either `true`, `null`, a string pointing to a module to be resolved,
 or a conditions object.
 
-The specifier string does not perform any searching and must match exactly
-what is provided to the `require()` or `import`. Therefore, multiple specifiers
-may be needed in the policy if it uses multiple different strings to point
-to the same module (such as excluding the extension).
+The specifier string does not perform any searching and must match exactly what
+is provided to the `require()` or `import` except for a canonicalization step.
+Therefore, multiple specifiers may be needed in the policy if it uses multiple
+different strings to point to the same module (such as excluding the extension).
 
-If the value of the redirection is `true` the default searching algorithms are
-used to find the module.
+Specifier strings are canonicalized but not resolved prior to be used for
+matching in order to have some compatibility with import maps, for example if a
+resource `file:///C:/app/server.js` was given the following redirection from a
+policy located at `file:///C:/app/policy.json`:
+
+```json
+{
+  "resources": {
+    "file:///C:/app/utils.js": {
+      "dependencies": {
+        "./utils.js": "./utils-v2.js"
+      }
+    }
+  }
+}
+```
+
+Any specifier used to load `file:///C:/app/utils.js` would then be intercepted
+and redirected to `file:///C:/app/utils-v2.js` instead regardless of using an
+absolute or relative specifier. However, if a specifier that is not an absolute
+or relative URL string is used, it would not be intercepted. So, if an import
+such as `import('#utils')` was used, it would not be intercepted.
+
+If the value of the redirection is `true`, a "dependencies" field at the top of
+the policy file will be used. If that field at the top of the policy file is
+`true` the default node searching algorithms are used to find the module.
 
 If the value of the redirection is a string, it is resolved relative to
 the manifest and then immediately used without searching.
@@ -207,7 +231,8 @@ is found by recursively reducing the resource URL by removing segments for
 hash fragment. This leads to the eventual reduction of the URL to its origin.
 If the URL is non-special the scope will be located by the URL's origin. If no
 scope is found for the origin or in the case of opaque origins, a protocol
-string can be used as a scope.
+string can be used as a scope. If no scope is found for the URL's protocol, a
+final empty string `""` scope will be used.
 
 Note, `blob:` URLs adopt their origin from the path they contain, and so a scope
 of `"blob:https://nodejs.org"` will have no effect since no URL can have an
@@ -216,6 +241,61 @@ origin of `blob:https://nodejs.org`; URLs starting with
 thus `https:` for its protocol scope. For opaque origin `blob:` URLs they will
 have `blob:` for their protocol scope since they do not adopt origins.
 
+#### Example
+
+```json
+{
+  "scopes": {
+    "file:///C:/app/": {},
+    "file:": {},
+    "": {}
+  }
+}
+```
+
+Given a file located at `file:///C:/app/bin/main.js`, the following scopes would
+be checked in order:
+
+1. `"file:///C:/app/bin/"`
+
+This determines the policy for all file based resources within
+`"file:///C:/app/bin/"`. This is not in the `"scopes"` field of the policy and
+would be skipped. Adding this scope to the policy would cause it to be used
+prior to the `"file:///C:/app/"` scope.
+
+2. `"file:///C:/app/"`
+
+This determines the policy for all file based resources within
+`"file:///C:/app/"`. This is in the `"scopes"` field of the policy and it would
+determine the policy for the resource at `file:///C:/app/bin/main.js`. If the
+scope has `"cascade": true`, any unsatisfied queries about the resource would
+delegate to the next relevant scope for `file:///C:/app/bin/main.js`, `"file:"`.
+
+3. `"file:///C:/"`
+
+This determines the policy for all file based resources within `"file:///C:/"`.
+This is not in the `"scopes"` field of the policy and would be skipped. It would
+not be used for `file:///C:/app/bin/main.js` unless `"file:///"` is set to
+cascade or is not in the `"scopes"` of the policy.
+
+4. `"file:///"`
+
+This determines the policy for all file based resources on the `localhost`. This
+is not in the `"scopes"` field of the policy and would be skipped. It would not
+be used for `file:///C:/app/bin/main.js` unless `"file:///"` is set to cascade
+or is not in the `"scopes"` of the policy.
+
+5. `"file:"`
+
+This determines the policy for all file based resources. It would not be used
+for `file:///C:/app/bin/main.js` unless `"file:///"` is set to cascade or is not
+in the `"scopes"` of the policy.
+
+6. `""`
+
+This determines the policy for all resources. It would not be used for
+`file:///C:/app/bin/main.js` unless `"file:"` is set to cascade.
+
 #### Integrity using scopes
 
 Setting an integrity to `true` on a scope will set the integrity for any
@@ -284,5 +364,64 @@ The following example, would allow access to `fs` for all `data:` resources:
 }
 ```
 
-[relative-URL string]: https://url.spec.whatwg.org/#relative-url-with-fragment-string
+#### Example: [import maps][] emulation
+
+Given an import map:
+
+```json
+{
+  "imports": {
+    "react": "./app/node_modules/react/index.js"
+  },
+  "scopes": {
+    "./ssr/": {
+      "react": "./app/node_modules/server-side-react/index.js"
+    }
+  }
+}
+```
+
+```json
+{
+  "dependencies": true,
+  "scopes": {
+    "": {
+      "cascade": true,
+      "dependencies": {
+        "react": "./app/node_modules/react/index.js"
+      }
+    },
+    "./ssr/": {
+      "cascade": true,
+      "dependencies": {
+        "react": "./app/node_modules/server-side-react/index.js"
+      }
+    }
+  }
+}
+```
+
+Import maps assume you can get any resource by default. This means
+`"dependencies"` at the top level of the policy should be set to `true`.
+Policies require this to be opt-in since it enables all resources of the
+application cross linkage which doesn't make sense for many scenarios. They also
+assume any given scope has access to any scope above its allowed dependencies;
+all scopes emulating import maps must set `"cascade": true`.
+
+Import maps only have a single top level scope for their "imports". So for
+emulating `"imports"` use the `""` scope. For emulating `"scopes"` use the
+`"scopes"` in a similar manner to how `"scopes"` works in import maps.
+
+Caveats: Policies do not use string matching for various finding of scope. They
+do URL traversals. This means things like `blob:` and `data:` URLs might not be
+entirely interoperable between the two systems. For example import maps can
+partially match a `data:` or `blob:` URL by partitioning the URL on a `/`
+character, policies intentionally cannot. For `blob:` URLs import map scopes do
+not adopt the origin of the `blob:` URL.
+
+Additionally, import maps only work on `import` so it may be desirable to add a
+`"import"` condition to all dependency mappings.
+
+[import maps]: https://url.spec.whatwg.org/#relative-url-with-fragment-string
+[relative-url string]: https://url.spec.whatwg.org/#relative-url-with-fragment-string
 [special schemes]: https://url.spec.whatwg.org/#special-scheme
diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 2e0cc23a2b..91d03d0874 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -1266,6 +1266,9 @@ E('ERR_MANIFEST_INTEGRITY_MISMATCH',
 E('ERR_MANIFEST_INVALID_RESOURCE_FIELD',
   'Manifest resource %s has invalid property value for %s',
   TypeError);
+E('ERR_MANIFEST_INVALID_SPECIFIER',
+  'Manifest resource %s has invalid dependency mapping %s',
+  TypeError);
 E('ERR_MANIFEST_TDZ', 'Manifest initialization has not yet run', Error);
 E('ERR_MANIFEST_UNKNOWN_ONERROR',
   'Manifest specified unknown error behavior "%s".',
diff --git a/lib/internal/policy/manifest.js b/lib/internal/policy/manifest.js
index a8420343db..42ff63e87d 100644
--- a/lib/internal/policy/manifest.js
+++ b/lib/internal/policy/manifest.js
@@ -1,12 +1,15 @@
 'use strict';
 
+// #region imports
 const {
   ArrayIsArray,
+  ArrayPrototypeSort,
   ObjectCreate,
   ObjectEntries,
   ObjectFreeze,
   ObjectKeys,
   ObjectSetPrototypeOf,
+  RegExpPrototypeExec,
   RegExpPrototypeTest,
   SafeMap,
   SafeSet,
@@ -16,12 +19,9 @@ const {
   uncurryThis,
 } = primordials;
 const {
-  canBeRequiredByUsers
-} = require('internal/bootstrap/loaders').NativeModule;
-const {
   ERR_MANIFEST_ASSERT_INTEGRITY,
-  ERR_MANIFEST_INTEGRITY_MISMATCH,
   ERR_MANIFEST_INVALID_RESOURCE_FIELD,
+  ERR_MANIFEST_INVALID_SPECIFIER,
   ERR_MANIFEST_UNKNOWN_ONERROR,
 } = require('internal/errors').codes;
 let debug = require('internal/util/debuglog').debuglog('policy', (fn) => {
@@ -37,12 +37,13 @@ const HashDigest = uncurryThis(crypto.Hash.prototype.digest);
 const BufferToString = uncurryThis(Buffer.prototype.toString);
 const kRelativeURLStringPattern = /^\.{0,2}\//;
 const { getOptionValue } = require('internal/options');
-const shouldAbortOnUncaughtException =
-  getOptionValue('--abort-on-uncaught-exception');
+const shouldAbortOnUncaughtException = getOptionValue(
+  '--abort-on-uncaught-exception'
+);
 const { abort, exit, _rawDebug } = process;
+// #endregion
 
-const kTerminate = () => null;
-
+// #region constants
 // From https://url.spec.whatwg.org/#special-scheme
 const kSpecialSchemes = new SafeSet([
   'file:',
@@ -53,7 +54,14 @@ const kSpecialSchemes = new SafeSet([
   'wss:',
 ]);
 
+/**
+ * @type {symbol}
+ */
 const kCascade = Symbol('cascade');
+/**
+ * @type {symbol}
+ */
+const kFallThrough = Symbol('fall through');
 
 function REACTION_THROW(error) {
   throw error;
@@ -70,31 +78,306 @@ function REACTION_EXIT(error) {
 function REACTION_LOG(error) {
   _rawDebug(error.stack);
 }
+
+// #endregion
+
+// #region DependencyMapperInstance
+class DependencyMapperInstance {
+  /**
+   * @type {string}
+   */
+  href;
+  /**
+   * @type {DependencyMap | undefined}
+   */
+  #dependencies;
+  /**
+   * @type {PatternDependencyMap | undefined}
+   */
+  #patternDependencies;
+  /**
+   * @type {DependencyMapperInstance | null | undefined}
+   */
+  #parentDependencyMapper;
+  /**
+   * @type {boolean}
+   */
+  #normalized = false;
+  /**
+   * @type {boolean}
+   */
+  cascade;
+  /**
+   * @type {boolean}
+   */
+  allowSameHREFScope;
+  /**
+   * @param {string} parentHREF
+   * @param {DependencyMap | undefined} dependencies
+   * @param {boolean} cascade
+   * @param {boolean} allowSameHREFScope
+   */
+  constructor(
+    parentHREF,
+    dependencies,
+    cascade = false,
+    allowSameHREFScope = false) {
+    this.href = parentHREF;
+    if (dependencies === kFallThrough ||
+        dependencies === undefined ||
+        dependencies === null) {
+      this.#dependencies = dependencies;
+      this.#patternDependencies = undefined;
+    } else {
+      const patterns = [];
+      for (const { 0: key } of ObjectEntries(dependencies)) {
+        if (StringPrototypeEndsWith(key, '*')) {
+          const target = RegExpPrototypeExec(/^([^*]*)\*([^*]*)$/);
+          if (!target) {
+            throw new ERR_MANIFEST_INVALID_SPECIFIER(
+              this.href,
+              target +
+                ', pattern needs to have a single' +
+                'trailing "*" in target');
+          }
+          const prefix = target[1];
+          const suffix = target[2];
+          patterns.push([
+            target.slice(0, -1),
+            [prefix, suffix],
+          ]);
+        }
+      }
+      ArrayPrototypeSort(patterns, (a, b) => {
+        return a[0] < b[0] ? -1 : 1;
+      });
+      this.#dependencies = dependencies;
+      this.#patternDependencies = patterns;
+    }
+    this.cascade = cascade;
+    this.allowSameHREFScope = allowSameHREFScope;
+    ObjectFreeze(this);
+  }
+  /**
+   *
+   * @param {string} normalizedSpecifier
+   * @param {Set<string>} conditions
+   * @param {Manifest} manifest
+   * @returns {URL | typeof kFallThrough | null}
+   */
+  _resolveAlreadyNormalized(normalizedSpecifier, conditions, manifest) {
+    let dependencies = this.#dependencies;
+    debug(this.href, 'resolving', normalizedSpecifier);
+    if (dependencies === kFallThrough) return true;
+    if (dependencies !== undefined && typeof dependencies === 'object') {
+      const normalized = this.#normalized;
+      if (normalized !== true) {
+        /**
+         * @type {Record<string, string>}
+         */
+        const normalizedDependencyMap = ObjectCreate(null);
+        for (let specifier in dependencies) {
+          const target = dependencies[specifier];
+          specifier = canonicalizeSpecifier(specifier, manifest.href);
+          normalizedDependencyMap[specifier] = target;
+        }
+        ObjectFreeze(normalizedDependencyMap);
+        dependencies = normalizedDependencyMap;
+        this.#dependencies = normalizedDependencyMap;
+        this.#normalized = true;
+      }
+      debug(dependencies);
+      if (normalizedSpecifier in dependencies === true) {
+        const to = searchDependencies(
+          this.href,
+          dependencies[normalizedSpecifier],
+          conditions
+        );
+        debug({ to });
+        if (to === true) {
+          return true;
+        }
+        let ret;
+        if (parsedURLs && parsedURLs.has(to)) {
+          ret = parsedURLs.get(to);
+        } else if (RegExpPrototypeTest(kRelativeURLStringPattern, to)) {
+          ret = resolve(to, manifest.href);
+        } else {
+          ret = resolve(to);
+        }
+        return ret;
+      }
+    }
+    const { cascade } = this;
+    if (cascade !== true) {
+      return null;
+    }
+    let parentDependencyMapper = this.#parentDependencyMapper;
+    if (parentDependencyMapper === undefined) {
+      parentDependencyMapper = manifest.getScopeDependencyMapper(
+        this.href,
+        this.allowSameHREFScope
+      );
+      this.#parentDependencyMapper = parentDependencyMapper;
+    }
+    if (parentDependencyMapper === null) {
+      return null;
+    }
+    return parentDependencyMapper._resolveAlreadyNormalized(
+      normalizedSpecifier,
+      conditions,
+      manifest
+    );
+  }
+}
+
+const kArbitraryDependencies = new DependencyMapperInstance(
+  'arbitrary dependencies',
+  kFallThrough,
+  false,
+  true
+);
+const kNoDependencies = new DependencyMapperInstance(
+  'no dependencies',
+  null,
+  false,
+  true
+);
 /**
+ * @param {string} href
+ * @param {JSONDependencyMap} dependencies
+ * @param {boolean} cascade
+ * @param {Map<string | null | undefined, DependencyMapperInstance>} store
+ */
+const insertDependencyMap = (
+  href,
+  dependencies,
+  cascade,
+  allowSameHREFScope,
+  store
+) => {
+  if (cascade !== undefined && typeof cascade !== 'boolean') {
+    throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(href, 'cascade');
+  }
+  if (dependencies === true) {
+    store.set(href, kArbitraryDependencies);
+    return;
+  }
+  if (dependencies === null || dependencies === undefined) {
+    store.set(
+      href,
+      cascade ?
+        new DependencyMapperInstance(href, null, true, allowSameHREFScope) :
+        kNoDependencies
+    );
+    return;
+  }
+  if (objectButNotArray(dependencies)) {
+    store.set(
+      href,
+      new DependencyMapperInstance(
+        href,
+        dependencies,
+        cascade,
+        allowSameHREFScope
+      )
+    );
+    return;
+  }
+  throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(href, 'dependencies');
+};
+/**
+ * Finds the longest key within `this.#scopeDependencies` that covers a
+ * specific HREF
+ * @param {string} href
+ * @param {ScopeStore} scopeStore
+ * @returns {null | string}
+ */
+function findScopeHREF(href, scopeStore, allowSame) {
+  let protocol;
+  if (href !== '') {
+    // default URL parser does some stuff to special urls... skip if this is
+    // just the protocol
+    if (RegExpPrototypeTest(/^[^:]*[:]$/, href)) {
+      protocol = href;
+    } else {
+      let currentURL = new URL(href);
+      const normalizedHREF = currentURL.href;
+      protocol = currentURL.protocol;
+      // Non-opaque blobs adopt origins
+      if (protocol === 'blob:' && currentURL.origin !== 'null') {
+        currentURL = new URL(currentURL.origin);
+        protocol = currentURL.protocol;
+      }
+      // Only a few schemes are hierarchical
+      if (kSpecialSchemes.has(currentURL.protocol)) {
+        // Make first '..' act like '.'
+        if (!StringPrototypeEndsWith(currentURL.pathname, '/')) {
+          currentURL.pathname += '/';
+        }
+        let lastHREF;
+        let currentHREF = currentURL.href;
+        do {
+          if (scopeStore.has(currentHREF)) {
+            if (allowSame || currentHREF !== normalizedHREF) {
+              return currentHREF;
+            }
+          }
+          lastHREF = currentHREF;
+          currentURL = new URL('..', currentURL);
+          currentHREF = currentURL.href;
+        } while (lastHREF !== currentHREF);
+      }
+    }
+  }
+  if (scopeStore.has(protocol)) {
+    if (allowSame || protocol !== href) return protocol;
+  }
+  if (scopeStore.has('')) {
+    if (allowSame || '' !== href) return '';
+  }
+  return null;
+}
+// #endregion
+
+/**
+ * @typedef {Record<string, string> | typeof kFallThrough} DependencyMap
+ * @typedef {Array<[string, [string, string]]>} PatternDependencyMap
+ * @typedef {Record<string, string> | null | true} JSONDependencyMap
+ */
+/**
+ * @typedef {Map<string, any>} ScopeStore
  * @typedef {(specifier: string) => true | URL} DependencyMapper
- * @typedef {Record<string, string> | true} DependencyMap
- * @typedef {true | string | SRI[]} Integrity
+ * @typedef {boolean | string | SRI[] | typeof kCascade} Integrity
  */
 
 class Manifest {
+  #defaultDependencies;
   /**
-   * @type {Map<string | null | undefined, DependencyMapper>}
-   *
-   * Used to compare a resource to the content body at the resource.
-   * `true` is used to signify that all integrities are allowed, otherwise,
-   * SRI strings are parsed to compare with the body.
+   * @type {string}
+   */
+  href;
+  /**
+   * @type {(err: Error) => void}
    *
-   * Separate from #resourceDependencies due to conflicts with things like
-   * `blob:` being both a scope and a resource potentially as well as
-   * `file:` being parsed to `file:///` instead of remaining host neutral.
+   * Performs default action for what happens when a manifest encounters
+   * a violation such as abort()ing or exiting the process, throwing the error,
+   * or logging the error.
    */
-  #scopeDependencies = new SafeMap();
+  #reaction;
   /**
-   * @type {Map<string, true | null | 'cascade'>}
+   * @type {Map<string, DependencyMapperInstance>}
    *
-   * Used to allow arbitrary loading within a scope
+   * Used to find where a dependency is located.
+   *
+   * This stores functions to lazily calculate locations as needed.
+   * `true` is used to signify that the location is not specified
+   * by the manifest and default resolution should be allowed.
+   *
+   * The functions return `null` to signify that a dependency is
+   * not found
    */
-  #scopeIntegrities = new SafeMap();
+  #resourceDependencies = new SafeMap();
   /**
    * @type {Map<string, Integrity>}
    *
@@ -109,26 +392,23 @@ class Manifest {
    */
   #resourceIntegrities = new SafeMap();
   /**
-   * @type {Map<string, DependencyMapper>}
-   *
-   * Used to find where a dependency is located.
+   * @type {ScopeStore}
    *
-   * This stores functions to lazily calculate locations as needed.
-   * `true` is used to signify that the location is not specified
-   * by the manifest and default resolution should be allowed.
+   * Used to compare a resource to the content body at the resource.
+   * `true` is used to signify that all integrities are allowed, otherwise,
+   * SRI strings are parsed to compare with the body.
    *
-   * The functions return `null` to signify that a dependency is
-   * not found
+   * Separate from #resourceDependencies due to conflicts with things like
+   * `blob:` being both a scope and a resource potentially as well as
+   * `file:` being parsed to `file:///` instead of remaining host neutral.
    */
-  #resourceDependencies = new SafeMap();
+  #scopeDependencies = new SafeMap();
   /**
-   * @type {(err: Error) => void}
+   * @type {Map<string, boolean | null | typeof kCascade>}
    *
-   * Performs default action for what happens when a manifest encounters
-   * a violation such as abort()ing or exiting the process, throwing the error,
-   * or logging the error.
+   * Used to allow arbitrary loading within a scope
    */
-  #reaction = null;
+  #scopeIntegrities = new SafeMap();
   /**
    * `obj` should match the policy file format described in the docs
    * it is expected to not have prototype pollution issues either by reassigning
@@ -137,17 +417,16 @@ class Manifest {
    * `manifestURL` is a URL to resolve relative locations against.
    *
    * @param {object} obj
-   * @param {string} manifestURL
+   * @param {string} manifestHREF
    */
-  constructor(obj, manifestURL) {
+  constructor(obj, manifestHREF) {
+    this.href = manifestHREF;
     const scopes = this.#scopeDependencies;
-    scopes.set(null, kTerminate);
-    scopes.set(undefined, kTerminate);
     const integrities = this.#resourceIntegrities;
-    const dependencies = this.#resourceDependencies;
+    const resourceDependencies = this.#resourceDependencies;
     let reaction = REACTION_THROW;
 
-    if (obj.onerror) {
+    if (objectButNotArray(obj) && 'onerror' in obj) {
       const behavior = obj.onerror;
       if (behavior === 'throw') {
       } else if (behavior === 'exit') {
@@ -160,319 +439,96 @@ class Manifest {
     }
 
     this.#reaction = reaction;
-    const jsonResourcesEntries = ObjectEntries(obj.resources ?? {});
-    const jsonScopesEntries = ObjectEntries(obj.scopes ?? {});
-
-    function searchDependencies(resourceHREF, target, conditions) {
-      if (
-        target &&
-        typeof target === 'object' &&
-        !ArrayIsArray(target)
-      ) {
-        const keys = ObjectKeys(target);
-        for (let i = 0; i < keys.length; i++) {
-          const key = keys[i];
-          if (conditions.has(key)) {
-            const ret = searchDependencies(
-              resourceHREF,
-              target[key],
-              conditions);
-            if (ret != null) {
-              return ret;
-            }
-          }
-        }
-      } else if (typeof target === 'string') {
-        return target;
-      } else if (target === true) {
-        return target;
-      } else {
-        throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(
-          resourceHREF,
-          'dependencies');
-      }
-      return null;
-    }
-
-    /**
-     * @param {string} resourceHREF
-     * @param {{[key: string]: string | true}} dependencyMap
-     * @param {boolean} cascade
-     * @returns {DependencyMapper}
-     */
-    const createDependencyMapper = (
-      resourceHREF,
-      dependencyMap,
-      cascade
-    ) => {
-      let parentDeps;
-      return (toSpecifier, conditions) => {
-        if (toSpecifier in dependencyMap !== true) {
-          if (cascade === true) {
-            /** @type {string | null} */
-            let scopeHREF = resourceHREF;
-            if (typeof parentDeps === 'undefined') {
-              do {
-                scopeHREF = this.#findScopeHREF(scopeHREF);
-                if (scopeHREF === resourceHREF) {
-                  scopeHREF = null;
-                }
-                if (scopes.has(scopeHREF)) {
-                  break;
-                }
-              } while (
-                scopeHREF !== null
-              );
-              parentDeps = scopes.get(scopeHREF);
-            }
-            return parentDeps(toSpecifier);
-          }
-          return null;
-        }
-        const to = searchDependencies(
-          resourceHREF,
-          dependencyMap[toSpecifier],
-          conditions);
-        if (to === true) {
-          return true;
-        }
-        if (parsedURLs.has(to)) {
-          return parsedURLs.get(to);
-        } else if (canBeRequiredByUsers(to)) {
-          const href = `node:${to}`;
-          const resolvedURL = new URL(href);
-          parsedURLs.set(to, resolvedURL);
-          parsedURLs.set(href, resolvedURL);
-          return resolvedURL;
-        } else if (RegExpPrototypeTest(kRelativeURLStringPattern, to)) {
-          const resolvedURL = new URL(to, manifestURL);
-          const href = resourceHREF;
-          parsedURLs.set(to, resolvedURL);
-          parsedURLs.set(href, resolvedURL);
-          return resolvedURL;
-        }
-        const resolvedURL = new URL(to);
-        const href = resourceHREF;
-        parsedURLs.set(to, resolvedURL);
-        parsedURLs.set(href, resolvedURL);
-        return resolvedURL;
-      };
-    };
-
-    /**
-     * Stores URLs keyed by string specifier relative to the manifest
-     * @type {Map<string, URL>}
-     */
-    const parsedURLs = new SafeMap();
+    const jsonResourcesEntries = ObjectEntries(
+      obj.resources ?? ObjectCreate(null)
+    );
+    const jsonScopesEntries = ObjectEntries(obj.scopes ?? ObjectCreate(null));
+    const defaultDependencies = obj.dependencies ?? ObjectCreate(null);
 
-    /**
-     * Resolves a valid url string against the manifest
-     * @param {string} originalHREF
-     * @returns {string}
-     */
-    const resolve = (originalHREF) => {
-      if (parsedURLs.has(originalHREF)) {
-        return parsedURLs.get(originalHREF).href;
-      } else if (
-        RegExpPrototypeTest(kRelativeURLStringPattern, originalHREF)
-      ) {
-        const resourceURL = new URL(originalHREF, manifestURL);
-        const resourceHREF = resourceURL.href;
-        parsedURLs.set(originalHREF, resourceURL);
-        parsedURLs.set(resourceURL.href, resourceURL);
-        return resourceHREF;
-      }
-      const resourceURL = new URL(originalHREF);
-      const resourceHREF = resourceURL.href;
-      parsedURLs.set(originalHREF, resourceURL);
-      return resourceHREF;
-    };
-
-    /**
-     * @param {string} resourceHREF
-     * @param {DependencyMap} dependencyMap
-     * @param {boolean} cascade
-     * @param {Map<string, DependencyMapper>} store
-     */
-    const insertDependencyMap = (
-      resourceHREF,
-      dependencyMap,
-      cascade,
-      store
-    ) => {
-      if (cascade !== undefined && typeof cascade !== 'boolean') {
-        throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(
-          resourceHREF,
-          'cascade');
-      }
-      if (dependencyMap === null || dependencyMap === undefined) {
-        dependencyMap = ObjectCreate(null);
-      }
-      if (
-        typeof dependencyMap === 'object' &&
-        !ArrayIsArray(dependencyMap)
-      ) {
-        const dependencyRedirectList = createDependencyMapper(
-          resourceHREF,
-          dependencyMap,
-          cascade);
-        store.set(resourceHREF, dependencyRedirectList);
-        return;
-      } else if (dependencyMap === true) {
-        const arbitraryDependencies = /** @type {()=>true} */() => true;
-        store.set(resourceHREF, arbitraryDependencies);
-        return;
-      }
-      throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(
-        resourceHREF,
-        'dependencies');
-    };
-    /**
-     * Does a special allowance for scopes to be non-valid URLs
-     * that are only protocol strings
-     * @param {string} resourceHREF
-     * @returns {string}
-     */
-    const protocolOrResolve = (resourceHREF) => {
-      if (StringPrototypeEndsWith(resourceHREF, ':')) {
-        // URL parse will trim these anyway, save the compute
-        resourceHREF = StringPrototypeReplace(
-          resourceHREF,
-          // eslint-disable-next-line
-          /^[\x00-\x1F\x20]|\x09\x0A\x0D|[\x00-\x1F\x20]$/g,
-          ''
-        );
-        if (RegExpPrototypeTest(/^[a-zA-Z][a-zA-Z+\-.]*:$/, resourceHREF)) {
-          return resourceHREF;
-        }
-      }
-      return resolve(resourceHREF);
-    };
+    this.#defaultDependencies = new DependencyMapperInstance(
+      'default',
+      defaultDependencies === true ? kFallThrough : defaultDependencies,
+      false
+    );
 
     for (let i = 0; i < jsonResourcesEntries.length; i++) {
-      const { 0: originalHREF, 1: resourceDescriptor } =
-        jsonResourcesEntries[i];
-      const cascade = resourceDescriptor.cascade;
-      const dependencyMap = resourceDescriptor.dependencies;
-      const resourceHREF = resolve(originalHREF);
+      const { 0: originalHREF, 1: descriptor } = jsonResourcesEntries[i];
+      const { cascade, dependencies, integrity } = descriptor;
+      const href = resolve(originalHREF, manifestHREF).href;
 
-      const integrity = resourceDescriptor.integrity;
       if (typeof integrity !== 'undefined') {
         debug('Manifest contains integrity for resource %s', originalHREF);
-        if (integrities.has(resourceHREF)) {
-          if (integrities.get(resourceHREF) !== integrity) {
-            throw new ERR_MANIFEST_INTEGRITY_MISMATCH(resourceHREF);
-          }
-        }
         if (typeof integrity === 'string') {
-          integrities.set(resourceHREF, integrity);
+          integrities.set(href, integrity);
         } else if (integrity === true) {
-          integrities.set(resourceHREF, true);
+          integrities.set(href, true);
         } else {
-          throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(
-            resourceHREF,
-            'integrity');
+          throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(href, 'integrity');
         }
       } else {
-        integrities.set(resourceHREF, cascade ? kCascade : null);
+        integrities.set(href, cascade === true ? kCascade : false);
       }
-      insertDependencyMap(resourceHREF, dependencyMap, cascade, dependencies);
+      insertDependencyMap(
+        href,
+        dependencies,
+        cascade,
+        true,
+        resourceDependencies
+      );
     }
 
     const scopeIntegrities = this.#scopeIntegrities;
     for (let i = 0; i < jsonScopesEntries.length; i++) {
-      const { 0: originalHREF, 1: scopeDescriptor } = jsonScopesEntries[i];
-      const integrity = scopeDescriptor.integrity;
-      const cascade = scopeDescriptor.cascade;
-      const dependencyMap = scopeDescriptor.dependencies;
-      const resourceHREF = protocolOrResolve(originalHREF);
+      const { 0: originalHREF, 1: descriptor } = jsonScopesEntries[i];
+      const { cascade, dependencies, integrity } = descriptor;
+      const href = emptyOrProtocolOrResolve(originalHREF, manifestHREF);
       if (typeof integrity !== 'undefined') {
         debug('Manifest contains integrity for scope %s', originalHREF);
-        if (scopeIntegrities.has(resourceHREF)) {
-          if (scopeIntegrities.get(resourceHREF) !== integrity) {
-            throw new ERR_MANIFEST_INTEGRITY_MISMATCH(resourceHREF);
-          }
-        }
         if (integrity === true) {
-          scopeIntegrities.set(resourceHREF, true);
+          scopeIntegrities.set(href, true);
         } else {
-          throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(
-            resourceHREF,
-            'integrity');
+          throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(href, 'integrity');
         }
       } else {
-        scopeIntegrities.set(resourceHREF, cascade ? kCascade : null);
+        scopeIntegrities.set(href, cascade === true ? kCascade : false);
       }
-      insertDependencyMap(resourceHREF, dependencyMap, cascade, scopes);
+      insertDependencyMap(href, dependencies, cascade, false, scopes);
     }
 
     ObjectFreeze(this);
   }
 
   /**
-   * Finds the longest key within `this.#scopeDependencies` that covers a
-   * specific HREF
-   * @param {string} href
-   * @returns {null | string}
-   */
-  #findScopeHREF = (href) => {
-    let currentURL = new URL(href);
-    let protocol = currentURL.protocol;
-    // Non-opaque blobs adopt origins
-    if (protocol === 'blob:' && currentURL.origin !== 'null') {
-      currentURL = new URL(currentURL.origin);
-      protocol = currentURL.protocol;
-    }
-    // Only a few schemes are hierarchical
-    if (kSpecialSchemes.has(currentURL.protocol)) {
-      // Make first '..' act like '.'
-      if (!StringPrototypeEndsWith(currentURL.pathname, '/')) {
-        currentURL.pathname += '/';
-      }
-      let lastHREF;
-      let currentHREF = currentURL.href;
-      do {
-        if (this.#scopeDependencies.has(currentHREF)) {
-          return currentHREF;
-        }
-        lastHREF = currentHREF;
-        currentURL = new URL('..', currentURL);
-        currentHREF = currentURL.href;
-      } while (lastHREF !== currentHREF);
-    }
-    if (this.#scopeDependencies.has(protocol)) {
-      return protocol;
-    }
-    return null;
-  }
-
-  #createResolver = (resolve) => {
-    return {
-      resolve: (to, conditions) => resolve(`${to}`, conditions),
-      reaction: this.#reaction
-    };
-  }
-
-  /**
    * @param {string} requester
+   * @returns {{resolve: any, reaction: (err: any) => void}}
    */
   getDependencyMapper(requester) {
     const requesterHREF = `${requester}`;
     const dependencies = this.#resourceDependencies;
-    if (dependencies.has(requesterHREF)) {
-      return this.#createResolver(
-        dependencies.get(requesterHREF) ||
-        (() => null)
-      );
-    }
-    const scopes = this.#scopeDependencies;
-    if (scopes.size !== 0) {
-      const scopeHREF = this.#findScopeHREF(requesterHREF);
-      if (typeof scopeHREF === 'string') {
-        return this.#createResolver(scopes.get(scopeHREF));
-      }
-    }
-    return this.#createResolver(() => null);
+    /**
+     * @type {DependencyMapperInstance}
+     */
+    const instance = (
+      dependencies.has(requesterHREF) ?
+        dependencies.get(requesterHREF) ?? null :
+        this.getScopeDependencyMapper(requesterHREF, true)
+    ) ?? this.#defaultDependencies;
+    return {
+      resolve: (specifier, conditions) => {
+        const normalizedSpecifier = canonicalizeSpecifier(
+          specifier,
+          requesterHREF
+        );
+        const result = instance._resolveAlreadyNormalized(
+          normalizedSpecifier,
+          conditions,
+          this
+        );
+        if (result === kFallThrough) return true;
+        return result;
+      },
+      reaction: this.#reaction,
+    };
   }
 
   assertIntegrity(url, content) {
@@ -496,10 +552,7 @@ class Manifest {
       if (ArrayIsArray(integrityEntries)) {
         // Avoid clobbered Symbol.iterator
         for (let i = 0; i < integrityEntries.length; i++) {
-          const {
-            algorithm,
-            value: expected
-          } = integrityEntries[i];
+          const { algorithm, value: expected } = integrityEntries[i];
           const hash = createHash(algorithm);
           // TODO(tniessen): the content should not be passed as a string in the
           // first place, see https://github.com/nodejs/node/issues/39707
@@ -509,10 +562,7 @@ class Manifest {
             timingSafeEqual(digest, expected)) {
             return true;
           }
-          realIntegrities.set(
-            algorithm,
-            BufferToString(digest, 'base64')
-          );
+          realIntegrities.set(algorithm, BufferToString(digest, 'base64'));
         }
       }
 
@@ -521,7 +571,7 @@ class Manifest {
         this.#reaction(error);
       }
     }
-    let scope = this.#findScopeHREF(href);
+    let scope = findScopeHREF(href, this.#scopeIntegrities, true);
     while (scope !== null) {
       if (this.#scopeIntegrities.has(scope)) {
         const entry = this.#scopeIntegrities.get(scope);
@@ -532,8 +582,8 @@ class Manifest {
           break;
         }
       }
-      const nextScope = this.#findScopeHREF(new URL('..', scope));
-      if (!nextScope || nextScope === scope) {
+      const nextScope = findScopeHREF(scope, this.#scopeDependencies, false);
+      if (!nextScope) {
         break;
       }
       scope = nextScope;
@@ -541,6 +591,24 @@ class Manifest {
     const error = new ERR_MANIFEST_ASSERT_INTEGRITY(url, realIntegrities);
     this.#reaction(error);
   }
+  /**
+   * @param {string} href
+   * @param {boolean} allowSameHREFScope
+   * @returns {DependencyMapperInstance | null}
+   */
+  getScopeDependencyMapper(href, allowSameHREFScope) {
+    if (href === null) {
+      return this.#defaultDependencies;
+    }
+    /** @type {string | null} */
+    const scopeHREF = findScopeHREF(
+      href,
+      this.#scopeDependencies,
+      allowSameHREFScope
+    );
+    if (scopeHREF === null) return this.#defaultDependencies;
+    return this.#scopeDependencies.get(scopeHREF);
+  }
 }
 
 // Lock everything down to avoid problems even if reference is leaked somehow
@@ -549,3 +617,107 @@ ObjectSetPrototypeOf(Manifest.prototype, null);
 ObjectFreeze(Manifest);
 ObjectFreeze(Manifest.prototype);
 module.exports = ObjectFreeze({ Manifest });
+
+// #region URL utils
+
+/**
+ * Attempts to canonicalize relative URL strings against a base URL string
+ * Does not perform I/O
+ * If not able to canonicalize, returns the original specifier
+ *
+ * This effectively removes the possibility of the return value being a relative
+ * URL string
+ * @param {string} specifier
+ * @param {string} base
+ * @returns {string}
+ */
+function canonicalizeSpecifier(specifier, base) {
+  try {
+    if (RegExpPrototypeTest(kRelativeURLStringPattern, specifier)) {
+      return resolve(specifier, base).href;
+    }
+    return resolve(specifier).href;
+  } catch {}
+  return specifier;
+}
+
+/**
+ * Does a special allowance for scopes to be non-valid URLs
+ * that are only protocol strings or the empty string
+ * @param {string} resourceHREF
+ * @param {string} [base]
+ * @returns {string}
+ */
+const emptyOrProtocolOrResolve = (resourceHREF, base) => {
+  if (resourceHREF === '') return '';
+  if (StringPrototypeEndsWith(resourceHREF, ':')) {
+    // URL parse will trim these anyway, save the compute
+    resourceHREF = StringPrototypeReplace(
+      resourceHREF,
+      // eslint-disable-next-line
+      /^[\x00-\x1F\x20]|\x09\x0A\x0D|[\x00-\x1F\x20]$/g,
+      ''
+    );
+    if (RegExpPrototypeTest(/^[a-zA-Z][a-zA-Z+\-.]*:$/, resourceHREF)) {
+      return resourceHREF;
+    }
+  }
+  return resolve(resourceHREF, base).href;
+};
+
+/**
+ * @type {Map<string, URL>}
+ */
+let parsedURLs;
+/**
+ * Resolves a valid url string and uses the parsed cache to avoid double parsing
+ * costs.
+ * @param {string} originalHREF
+ * @param {string} [base]
+ * @returns {Readonly<URL>}
+ */
+const resolve = (originalHREF, base) => {
+  parsedURLs = parsedURLs ?? new SafeMap();
+  if (parsedURLs.has(originalHREF)) {
+    return parsedURLs.get(originalHREF);
+  } else if (RegExpPrototypeTest(kRelativeURLStringPattern, originalHREF)) {
+    const resourceURL = new URL(originalHREF, base);
+    parsedURLs.set(resourceURL.href, resourceURL);
+    return resourceURL;
+  }
+  const resourceURL = new URL(originalHREF);
+  parsedURLs.set(originalHREF, resourceURL);
+  return resourceURL;
+};
+
+// #endregion
+
+/**
+ * @param {any} o
+ * @returns {o is object}
+ */
+function objectButNotArray(o) {
+  return o && typeof o === 'object' && !ArrayIsArray(o);
+}
+
+function searchDependencies(href, target, conditions) {
+  if (objectButNotArray(target)) {
+    const keys = ObjectKeys(target);
+    for (let i = 0; i < keys.length; i++) {
+      const key = keys[i];
+      if (conditions.has(key)) {
+        const ret = searchDependencies(href, target[key], conditions);
+        if (ret != null) {
+          return ret;
+        }
+      }
+    }
+  } else if (typeof target === 'string') {
+    return target;
+  } else if (target === true) {
+    return target;
+  } else {
+    throw new ERR_MANIFEST_INVALID_RESOURCE_FIELD(href, 'dependencies');
+  }
+  return null;
+}
diff --git a/test/fixtures/policy/canonicalize.mjs b/test/fixtures/policy/canonicalize.mjs
new file mode 100644
index 0000000000..64e7cd117a
--- /dev/null
+++ b/test/fixtures/policy/canonicalize.mjs
@@ -0,0 +1,5 @@
+import resolveAsFS from './dep.js';
+import fs from 'fs';
+
+let correct = resolveAsFS === fs && typeof resolveAsFS === 'object';
+process.exit(correct ? 0 : 1);
diff --git a/test/fixtures/policy/dependencies/dependencies-missing-policy-default-true.json b/test/fixtures/policy/dependencies/dependencies-missing-policy-default-true.json
new file mode 100644
index 0000000000..10ab862d2b
--- /dev/null
+++ b/test/fixtures/policy/dependencies/dependencies-missing-policy-default-true.json
@@ -0,0 +1,13 @@
+{
+  "dependencies": true,
+  "resources": {
+    "../parent.js": {
+      "cascade": true,
+      "integrity": true
+    },
+    "../dep.js": {
+      "cascade": true,
+      "integrity": true
+    }
+  }
+}
\ No newline at end of file
diff --git a/test/fixtures/policy/dependencies/dependencies-redirect-builtin-policy.json b/test/fixtures/policy/dependencies/dependencies-redirect-builtin-policy.json
index 437228a2e5..7d2715f96a 100644
--- a/test/fixtures/policy/dependencies/dependencies-redirect-builtin-policy.json
+++ b/test/fixtures/policy/dependencies/dependencies-redirect-builtin-policy.json
@@ -3,7 +3,7 @@
     "../parent.js": {
       "integrity": true,
       "dependencies": {
-        "./dep.js": "node:util"
+        "../dep.js": "node:util"
       }
     }
   }
diff --git a/test/fixtures/policy/dependencies/dependencies-redirect-policy.json b/test/fixtures/policy/dependencies/dependencies-redirect-policy.json
index 993a683f10..c5b73403d5 100644
--- a/test/fixtures/policy/dependencies/dependencies-redirect-policy.json
+++ b/test/fixtures/policy/dependencies/dependencies-redirect-policy.json
@@ -3,7 +3,7 @@
     "../parent.js": {
       "integrity": true,
       "dependencies": {
-        "./dep.js": "../dep.js"
+        "../dep.js": "../dep.js"
       }
     },
     "../dep.js": {
diff --git a/test/fixtures/policy/dependencies/dependencies-redirect-unknown-builtin-policy.json b/test/fixtures/policy/dependencies/dependencies-redirect-unknown-builtin-policy.json
index db2046c6d3..a2bcb26762 100644
--- a/test/fixtures/policy/dependencies/dependencies-redirect-unknown-builtin-policy.json
+++ b/test/fixtures/policy/dependencies/dependencies-redirect-unknown-builtin-policy.json
@@ -3,7 +3,7 @@
     "../parent.js": {
       "integrity": true,
       "dependencies": {
-        "./dep.js": "node:404"
+        "../dep.js": "node:404"
       }
     }
   }
diff --git a/test/fixtures/policy/dependencies/dependencies-scopes-relative-specifier.json b/test/fixtures/policy/dependencies/dependencies-scopes-relative-specifier.json
new file mode 100644
index 0000000000..7ce0b0262e
--- /dev/null
+++ b/test/fixtures/policy/dependencies/dependencies-scopes-relative-specifier.json
@@ -0,0 +1,12 @@
+{
+  "scopes": {
+    "file:": {
+      "integrity": true,
+      "cascade": true,
+      "dependencies": {
+        "fs": "node:fs",
+        "../dep.js": "node:fs"
+      }
+    }
+  }
+}
diff --git a/test/parallel/test-policy-dependencies.js b/test/parallel/test-policy-dependencies.js
index 157da82952..decc164dad 100644
--- a/test/parallel/test-policy-dependencies.js
+++ b/test/parallel/test-policy-dependencies.js
@@ -16,12 +16,13 @@ const dep = fixtures.path('policy', 'parent.js');
     'policy',
     'dependencies',
     'dependencies-redirect-policy.json');
-  const { status } = spawnSync(
+  const { status, stderr, stdout } = spawnSync(
     process.execPath,
     [
       '--experimental-policy', depPolicy, dep,
     ]
   );
+  console.log('%s\n%s', stderr, stdout);
   assert.strictEqual(status, 0);
 }
 {
@@ -55,12 +56,13 @@ const dep = fixtures.path('policy', 'parent.js');
     'policy',
     'dependencies',
     'dependencies-wildcard-policy.json');
-  const { status } = spawnSync(
+  const { status, stderr, stdout } = spawnSync(
     process.execPath,
     [
       '--experimental-policy', depPolicy, dep,
     ]
   );
+  console.log('%s\n%s', stderr, stdout);
   assert.strictEqual(status, 0);
 }
 {
@@ -80,6 +82,19 @@ const dep = fixtures.path('policy', 'parent.js');
   const depPolicy = fixtures.path(
     'policy',
     'dependencies',
+    'dependencies-missing-policy-default-true.json');
+  const { status } = spawnSync(
+    process.execPath,
+    [
+      '--experimental-policy', depPolicy, dep,
+    ]
+  );
+  assert.strictEqual(status, 0);
+}
+{
+  const depPolicy = fixtures.path(
+    'policy',
+    'dependencies',
     'dependencies-missing-policy.json');
   const { status } = spawnSync(
     process.execPath,
@@ -107,5 +122,25 @@ const dep = fixtures.path('policy', 'parent.js');
   assert.match(
     `${stderr}`,
     /SyntaxError: Named export 'doesNotExist' not found\./,
-    'Should give the real SyntaxError and position');
+    new Error('Should give the real SyntaxError and position'));
+}
+{
+  const depPolicy = fixtures.path(
+    'policy',
+    'dependencies',
+    'dependencies-scopes-relative-specifier.json');
+  const { status } = spawnSync(
+    process.execPath,
+    [
+      '--experimental-policy',
+      depPolicy,
+      fixtures.path('policy', 'canonicalize.mjs'),
+    ]
+  );
+  assert.strictEqual(
+    status,
+    0,
+    new Error(
+      'policies should canonicalize specifiers by default prior to matching')
+  );
 }
diff --git a/test/parallel/test-policy-scopes-dependencies.js b/test/parallel/test-policy-scopes-dependencies.js
index 53c4488614..f4b93a08e5 100644
--- a/test/parallel/test-policy-scopes-dependencies.js
+++ b/test/parallel/test-policy-scopes-dependencies.js
@@ -41,6 +41,41 @@ const assert = require('assert');
   {
     const manifest = new Manifest({
       scopes: {
+        '': {
+          dependencies: true
+        }
+      }
+    });
+
+    for (const href of baseURLs) {
+      assert.strictEqual(
+        manifest.getDependencyMapper(href).resolve('fs'),
+        true
+      );
+    }
+  }
+  {
+    const manifest = new Manifest({
+      scopes: {
+        '': {
+          dependencies: true
+        },
+        'file:': {
+          cascade: true
+        }
+      }
+    });
+
+    for (const href of baseURLs) {
+      assert.strictEqual(
+        manifest.getDependencyMapper(href).resolve('fs'),
+        true
+      );
+    }
+  }
+  {
+    const manifest = new Manifest({
+      scopes: {
         'file:': {
           dependencies: true
         }