core: add top-level runtimeError

lighthouse-core/lib/lh-error.js

@@ -174,5 +174,6 @@ const ERRORS = {
 
 /** @type {Record<keyof typeof ERRORS, LighthouseErrorDefinition>} */
 LighthouseError.errors = ERRORS;
+LighthouseError.NO_ERROR = 'NO_ERROR';
 module.exports = LighthouseError;
 

lighthouse-core/runner.js

@@ -294,19 +294,28 @@ class Runner {
   }
 
   /**
-   * Returns any runtimeError message found in artifacts.
+   * Returns first runtimeError found in artifacts.
    * @param {LH.Artifacts} artifacts
-   * @return {string|undefined}
+   * @return {LH.Result['runtimeError']}
    */
   static getArtifactRuntimeError(artifacts) {
     for (const possibleErrorArtifact of Object.values(artifacts)) {
       if (possibleErrorArtifact instanceof LHError && possibleErrorArtifact.lhrRuntimeError) {
         const errorMessage = possibleErrorArtifact.friendlyMessage ?
-          `${possibleErrorArtifact.friendlyMessage} (${possibleErrorArtifact.message})` :
-          possibleErrorArtifact.message;
-        return errorMessage;
+            `${possibleErrorArtifact.friendlyMessage} (${possibleErrorArtifact.message})` :
+            possibleErrorArtifact.message;
+
+        return {
+          code: possibleErrorArtifact.code,
+          message: errorMessage,
+        };
       }
     }
+
+    return {
+      code: LHError.NO_ERROR,
+      message: '',
+    };
   }
 
   /**

lighthouse-extension/app/src/lighthouse-ext-background.js

@@ -11,6 +11,7 @@ const background = require('./lighthouse-background');
 const ExtensionProtocol = require('../../../lighthouse-core/gather/connections/extension');
 const log = require('lighthouse-logger');
 const assetSaver = require('../../../lighthouse-core/lib/asset-saver.js');
+const LHError = require('../../../lighthouse-core/lib/lh-error.js');
 
 /** @type {Record<'mobile'|'desktop', LH.Config.Json>} */
 const LR_PRESETS = {
@@ -111,14 +112,29 @@ async function runLighthouseInLR(connection, url, flags, {lrDevice, categoryIDs,
     config.settings.onlyCategories = categoryIDs;
   }
 
-  const results = await lighthouse(url, flags, config, connection);
-  if (!results) return;
+  try {
+    const results = await lighthouse(url, flags, config, connection);
+    if (!results) return;
 
-  if (logAssets) {
-    await assetSaver.logAssets(results.artifacts, results.lhr.audits);
-  }
+    if (logAssets) {
+      await assetSaver.logAssets(results.artifacts, results.lhr.audits);
+    }
+    return results.report;
+  } catch (err) {
+    // If an error ruined the entire lighthouse run, attempt to return a meaningful error.
+    if (!(err instanceof LHError) || !err.lhrRuntimeError) {
+      throw err;
+    }
+
+    const runtimeError = {
+      code: err.code,
+      message: err.friendlyMessage ?
+          `${err.friendlyMessage} (${err.message})` :
+          err.message,
+    };
 
-  return results.report;
+    return JSON.stringify(runtimeError, null, 2);
+  }
 }
 
 /**

typings/lhr.d.ts

@@ -4,6 +4,8 @@
  * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
  */
 
+import LHError = require('../lighthouse-core/lib/lh-error.js');
+
 declare global {
   module LH {
     export type I18NMessageEntry = string | {path: string, values: any};
@@ -50,8 +52,8 @@ declare global {
       configSettings: Config.Settings;
       /** List of top-level warnings for this Lighthouse run. */
       runWarnings: string[];
-      /** A top-level error message that, if present, indicates a serious enough problem that the result may need to be discarded. */
-      runtimeError: string|undefined;
+      /** A top-level error message that, if present, indicates a serious enough problem that this Lighthouse result may need to be discarded. */
+      runtimeError: {code: string, message: string};
       /** The User-Agent string of the browser used run Lighthouse for these results. */
       userAgent: string;
       /** Information about the environment in which Lighthouse was run. */