feat(ses): Carry compartment names in error messages (#441)

packages/endo/src/assemble.js

@@ -161,7 +161,8 @@ export const assemble = (
     const compartment = new Compartment(endowments, exitModules, {
       resolveHook,
       importHook,
-      moduleMapHook
+      moduleMapHook,
+      name: location
     });
 
     compartments[compartmentName] = compartment;

packages/ses/NEWS.md

@@ -2,7 +2,12 @@ User-visible changes in SES:
 
 ## Next release
 
-* No changes yet.
+* Adds the `name` option to the `Compartment` constructor and `name` accessor
+  to the `Compartment` prototype.
+  Errors that propagate through the module loader will be rethrown anew with
+  the name of the module and compartment so they can be traced.
+  At this time, the intermediate stacks of the causal chain are lost.
+  https://github.com/Agoric/SES-shim/issues/440
 
 ## Release 0.10.2 (20-August-2020)
 

packages/ses/README.md

@@ -149,6 +149,7 @@ The `importHook` accepts a full specifier and asynchronously returns a
 import 'ses';
 
 const c1 = new Compartment({}, {}, {
+  name: "first compartment",
   resolveHook: (moduleSpecifier, moduleReferrer) => {
     return resolve(moduleSpecifier, moduleReferrer);
   },
@@ -171,6 +172,7 @@ module map of another Compartment, creating a link.
 const c2 = new Compartment({}, {
   'c1': c1.module('./main.js'),
 }, {
+  name: "second compartment",
   resolveHook,
   importHook,
 });

packages/ses/src/compartment-shim.js

@@ -94,10 +94,15 @@ const assertModuleHooks = compartment => {
 
 const CompartmentPrototype = {
   constructor: InertCompartment,
+
   get globalThis() {
     return privateFields.get(this).globalObject;
   },
 
+  get name() {
+    return privateFields.get(this).name;
+  },
+
   /**
    * @param {string} source is a JavaScript program grammar construction.
    * @param {{
@@ -204,6 +209,7 @@ export const makeCompartmentConstructor = (intrinsics, nativeBrander) => {
   function Compartment(endowments = {}, moduleMap = {}, options = {}) {
     // Extract options, and shallow-clone transforms.
     const {
+      name = '<unknown>',
       transforms = [],
       globalLexicals = {},
       resolveHook,
@@ -253,7 +259,7 @@ export const makeCompartmentConstructor = (intrinsics, nativeBrander) => {
     }
 
     const invalidNames = getOwnPropertyNames(globalLexicals).filter(
-      name => !isValidIdentifierName(name),
+      identifier => !isValidIdentifierName(identifier),
     );
     if (invalidNames.length) {
       throw new Error(
@@ -264,6 +270,7 @@ export const makeCompartmentConstructor = (intrinsics, nativeBrander) => {
     }
 
     privateFields.set(this, {
+      name,
       resolveHook,
       importHook,
       moduleMap,

packages/ses/src/module-load.js

@@ -34,12 +34,7 @@ const resolveAll = (imports, resolveHook, fullReferrerSpecifier) => {
   return freeze(resolvedImports);
 };
 
-// `load` asynchronously loads `StaticModuleRecords` and creates a complete
-// graph of `ModuleCompartmentRecords`.
-// The module records refer to each other by a reference to the dependency's
-// compartment and the specifier of the module within its own compartment.
-// This graph is then ready to be synchronously linked and executed.
-export const load = async (
+const loadWithoutErrorAnnotation = async (
   compartmentPrivateFields,
   moduleAliases,
   compartment,
@@ -73,6 +68,8 @@ export const load = async (
         )} because the key is not a module exports namespace, or is from another realm`,
       );
     }
+    // Behold: recursion.
+    // eslint-disable-next-line no-use-before-define
     const moduleRecord = await load(
       compartmentPrivateFields,
       moduleAliases,
@@ -109,9 +106,40 @@ export const load = async (
   // Await all dependencies to load, recursively.
   await Promise.all(
     values(resolvedImports).map(fullSpecifier =>
+      // Behold: recursion.
+      // eslint-disable-next-line no-use-before-define
       load(compartmentPrivateFields, moduleAliases, compartment, fullSpecifier),
     ),
   );
 
   return moduleRecord;
 };
+
+// `load` asynchronously loads `StaticModuleRecords` and creates a complete
+// graph of `ModuleCompartmentRecords`.
+// The module records refer to each other by a reference to the dependency's
+// compartment and the specifier of the module within its own compartment.
+// This graph is then ready to be synchronously linked and executed.
+export const load = async (
+  compartmentPrivateFields,
+  moduleAliases,
+  compartment,
+  moduleSpecifier,
+) => {
+  return loadWithoutErrorAnnotation(
+    compartmentPrivateFields,
+    moduleAliases,
+    compartment,
+    moduleSpecifier,
+  ).catch(error => {
+    const { name } = compartmentPrivateFields.get(compartment);
+    // TODO The following drops the causes' stacks.
+    // In the future, we should capture the causal chain.
+    // https://github.com/Agoric/SES-shim/issues/440
+    throw new error.constructor(
+      `${error.message}, loading ${q(moduleSpecifier)} in compartment ${q(
+        name,
+      )}`,
+    );
+  });
+};

packages/ses/src/whitelist.js

@@ -1782,6 +1782,7 @@ export const whitelist = {
     constructor: '%InertCompartment%',
     evaluate: fn,
     globalThis: getter,
+    name: getter,
     import: asyncFn,
     load: asyncFn,
     importNow: fn,

packages/ses/test/compartment-instance.test.js

@@ -45,6 +45,7 @@ test('Compartment instance', t => {
       'importNow',
       'load',
       'module',
+      'name',
       'globalThis',
       'toString',
     ].sort(),

packages/ses/test/compartment-prototype.test.js

@@ -21,6 +21,7 @@ test('Compartment prototype', t => {
       'importNow',
       'load',
       'module',
+      'name',
       'globalThis',
       'toString',
     ].sort(),