Stop the trace when multiple tabs are found.

lighthouse-cli/bin.ts

@@ -220,6 +220,8 @@ function showRuntimeError(err) {
 function handleError(err) {
   if (err.code === 'ECONNREFUSED') {
     showConnectionError();
+  } else if (err.message.toLowerCase().includes('multiple tabs')) {
+    console.error(err.message);
   } else {
     showRuntimeError(err);
   }

lighthouse-core/gather/drivers/cri.js

@@ -88,6 +88,10 @@ class CriConnection extends Connection {
   sendRawMessage(message) {
     this._ws.send(message);
   }
+
+  getCurrentTabId() {
+    return Promise.resolve(this._tab.id);
+  }
 }
 
 module.exports = CriConnection;

lighthouse-core/gather/drivers/driver.js

@@ -123,6 +123,14 @@ class Driver {
     return this._connection.sendCommand(method, params);
   }
 
+  /**
+   * Get current tab id
+   * @return {!Promise<string>}
+   */
+  getCurrentTabId() {
+    return Promise.reject(new Error('Not implemented'));
+  }
+
   evaluateScriptOnLoad(scriptSource) {
     return this.sendCommand('Page.addScriptToEvaluateOnLoad', {
       scriptSource
@@ -177,6 +185,74 @@ class Driver {
     });
   }
 
+  getServiceWorkerRegistrations() {
+    return new Promise((resolve, reject) => {
+      this.once('ServiceWorker.workerRegistrationUpdated', data => {
+        this.sendCommand('ServiceWorker.disable')
+          .then(_ => resolve(data), reject);
+      });
+
+      this.sendCommand('ServiceWorker.enable').catch(reject);
+    });
+  }
+
+  /**
+   * Rejects if any open tabs would share a service worker with the target URL.
+   * @param {!string} pageUrl
+   * @return {!Promise}
+   */
+  checkForMultipleTabsAttached(pageUrl) {
+    // Get necessary information of serviceWorkers
+    const getRegistrations = this.getServiceWorkerRegistrations();
+    const getVersions = this.getServiceWorkerVersions();
+    const getActiveTabId = this.getCurrentTabId();
+
+    return Promise.all([getRegistrations, getVersions, getActiveTabId]).then(res => {
+      const registrations = res[0].registrations;
+      const versions = res[1].versions;
+      const activeTabId = res[2];
+      const parsedURL = parseURL(pageUrl);
+      const origin = `${parsedURL.protocol}//${parsedURL.hostname}` +
+      (parsedURL.port ? `:${parsedURL.port}` : '');
+
+      let swHasMoreThanOneClient = false;
+      registrations
+        .filter(reg => {
+          const parsedURL = parseURL(reg.scopeURL);
+          const swOrigin = `${parsedURL.protocol}//${parsedURL.hostname}` +
+            (parsedURL.port ? `:${parsedURL.port}` : '');
+
+          return origin === swOrigin;
+        })
+        .forEach(reg => {
+          swHasMoreThanOneClient = !!versions.find(ver => {
+            // Check if any of the service workers are the same (registration id)
+            if (ver.registrationId !== reg.registrationId) {
+              return false;
+            }
+
+            // Check if the controlledClients are bigger than 1 and it's not the active tab
+            if (!ver.controlledClients || ver.controlledClients.length === 0) {
+              return false;
+            }
+
+            const multipleTabsAttached = ver.controlledClients.length > 1;
+            const oneInactiveTabIsAttached = ver.controlledClients[0] !== activeTabId;
+
+            return multipleTabsAttached || oneInactiveTabIsAttached;
+          });
+        });
+
+      if (swHasMoreThanOneClient) {
+        throw new Error(
+          'You probably have multiple tabs open to the same origin.'
+        );
+      }
+
+      return res;
+    });
+  }
+
   /**
    * If our main document URL redirects, we will update options.url accordingly
    * As such, options.url will always represent the post-redirected URL.

lighthouse-core/gather/drivers/extension.js

@@ -153,6 +153,22 @@ class ExtensionConnection extends Connection {
   getCurrentTabURL() {
     return this._queryCurrentTab().then(tab => tab.url);
   }
+
+  getCurrentTabId() {
+    return this.queryCurrentTab_().then(currentTab => {
+      return new Promise((resolve, reject) => {
+        chrome.debugger.getTargets(targets => {
+          const target = targets.find(target => target.tabId === currentTab.id);
+
+          if (!target) {
+            reject(new Error('We can\'t find a target id.'));
+          }
+
+          resolve(target.id);
+        });
+      });
+    });
+  }
 }
 
 module.exports = ExtensionConnection;

lighthouse-core/gather/gather-runner.js

@@ -27,9 +27,10 @@ const path = require('path');
  * 1. Setup
  *   A. driver.connect()
  *   B. GatherRunner.setupDriver()
- *     i. beginEmulation
- *     ii. cleanAndDisableBrowserCaches
- *     iii. clearDataForOrigin
+ *     i. checkForMultipleTabsAttached
+ *     ii. beginEmulation
+ *     iii. cleanAndDisableBrowserCaches
+ *     iiii. clearDataForOrigin
  *
  * 2. For each pass in the config:
  *   A. GatherRunner.beforePass()
@@ -85,12 +86,18 @@ class GatherRunner {
   static setupDriver(driver, options) {
     log.log('status', 'Initializing…');
     // Enable emulation if required.
-    return Promise.resolve(options.flags.mobile && driver.beginEmulation())
+    return driver.checkForMultipleTabsAttached(options.url)
+      .then(_ => options.flags.mobile && driver.beginEmulation())
       .then(_ => driver.enableRuntimeEvents())
       .then(_ => driver.cleanAndDisableBrowserCaches())
       .then(_ => driver.clearDataForOrigin(options.url));
   }
 
+  static disposeDriver(driver) {
+    log.log('status', 'Disconnecting from browser...');
+    driver.disconnect();
+  }
+
   /**
    * Navigates to about:blank and calls beforePass() on gatherers before tracing
    * has started and before navigation to the target page.
@@ -242,9 +249,13 @@ class GatherRunner {
         });
       })
       .then(_ => {
-        log.log('status', 'Disconnecting from browser...');
-        return driver.disconnect();
-      }).then(_ => {
+        // We dont need to hold up the reporting for the reload/disconnect,
+        // so we will not return a promise in here.
+        driver.reloadForCleanStateIfNeeded(options).then(_ => {
+          GatherRunner.disposeDriver(driver);
+        });
+      })
+      .then(_ => {
         // Collate all the gatherer results.
         const computedArtifacts = this.instantiateComputedArtifacts();
         const artifacts = Object.assign({}, computedArtifacts, tracingData);
@@ -259,6 +270,12 @@ class GatherRunner {
           });
         });
         return artifacts;
+      })
+      // cleanup on error
+      .catch(err => {
+        GatherRunner.disposeDriver(driver);
+
+        throw err;
       });
   }
 

lighthouse-core/test/gather/fake-driver.js

@@ -29,6 +29,12 @@ module.exports = {
   beginEmulation() {
     return Promise.resolve();
   },
+  checkForMultipleTabsAttached() {
+    return Promise.resolve();
+  },
+  reloadForCleanStateIfNeeded() {
+    return Promise.resolve();
+  },
   enableRuntimeEvents() {
     return Promise.resolve();
   },

lighthouse-core/test/gather/gather-runner-test.js

@@ -87,6 +87,9 @@ describe('GatherRunner', function() {
       enableRuntimeEvents() {
         return Promise.resolve();
       },
+      checkForMultipleTabsAttached() {
+        return Promise.resolve();
+      },
       cleanAndDisableBrowserCaches() {
         return Promise.resolve();
       },
@@ -114,6 +117,9 @@ describe('GatherRunner', function() {
       enableRuntimeEvents() {
         return Promise.resolve();
       },
+      checkForMultipleTabsAttached() {
+        return Promise.resolve();
+      },
       cleanAndDisableBrowserCaches() {
         return Promise.resolve();
       },

lighthouse-core/test/lib/drivers/driver-test.js

@@ -26,6 +26,32 @@ const assert = require('assert');
 const connection = new Connection();
 const driverStub = new Driver(connection);
 
+function createOnceStub(events) {
+  return (eventName, cb) => {
+    if (events[eventName]) {
+      return cb(events[eventName]);
+    }
+
+    throw Error(`Stub not implemented: ${eventName}`);
+  };
+}
+
+function createSWRegistration(id, url, isDeleted) {
+  return {
+    isDeleted: !!isDeleted,
+    registrationId: id,
+    scopeURL: url,
+  };
+}
+
+function createActiveWorker(id, url, controlledClients) {
+  return {
+    registrationId: id,
+    scriptURL: url,
+    controlledClients,
+  };
+}
+
 connection.sendCommand = function(command, params) {
   switch (command) {
     case 'DOM.getDocument':
@@ -34,6 +60,9 @@ connection.sendCommand = function(command, params) {
       return Promise.resolve({
         nodeId: params.selector === 'invalid' ? 0 : 231
       });
+    case 'ServiceWorker.enable':
+    case 'ServiceWorker.disable':
+      return Promise.resolve();
     default:
       throw Error(`Stub not implemented: ${command}`);
   }
@@ -83,3 +112,73 @@ describe('Browser Driver', () => {
     assert.equal(opts.url, req3.url, 'opts.url matches the last redirect');
   });
 });
+
+describe('Multiple tab check', () => {
+  it('will fail when multiple tabs are found with the same active serviceworker', () => {
+    const pageUrl = 'https://example.com/';
+    const swUrl = `${pageUrl}sw.js`;
+    const registrations = [
+      createSWRegistration(1, pageUrl),
+    ];
+    const versions = [
+      createActiveWorker(1, swUrl, ['unique'])
+    ];
+
+    driverStub.getCurrentTabId = () => Promise.resolve('unique2');
+    driverStub.once = createOnceStub({
+      'ServiceWorker.workerRegistrationUpdated': {
+        registrations
+      },
+      'ServiceWorker.workerVersionUpdated': {
+        versions
+      }
+    });
+
+    return driverStub.checkForMultipleTabsAttached(pageUrl)
+      .then(_ => assert.ok(false), _ => assert.ok(true));
+  });
+
+  it('will succeed when service worker is already registered on current tab', () => {
+    const pageUrl = 'https://example.com/';
+    const swUrl = `${pageUrl}sw.js`;
+    const registrations = [
+      createSWRegistration(1, pageUrl),
+    ];
+    const versions = [
+      createActiveWorker(1, swUrl, ['unique'])
+    ];
+
+    driverStub.getCurrentTabId = () => Promise.resolve('unique');
+    driverStub.once = createOnceStub({
+      'ServiceWorker.workerRegistrationUpdated': {
+        registrations
+      },
+      'ServiceWorker.workerVersionUpdated': {
+        versions
+      }
+    });
+
+    return driverStub.checkForMultipleTabsAttached(pageUrl)
+      .then(_ => assert.ok(true), _ => assert.ok(false));
+  });
+
+  it('will succeed when only one service worker loaded', () => {
+    const pageUrl = 'https://example.com/';
+    const swUrl = `${pageUrl}sw.js`;
+    const registrations = [createSWRegistration(1, pageUrl)];
+    const versions = [createActiveWorker(1, swUrl, [])];
+
+    driverStub.getCurrentTabId = () => Promise.resolve('unique');
+    driverStub.once = createOnceStub({
+      'ServiceWorker.workerRegistrationUpdated': {
+        registrations
+      },
+      'ServiceWorker.workerVersionUpdated': {
+        versions
+      }
+    });
+
+    return driverStub.checkForMultipleTabsAttached(pageUrl)
+      .then(_ => assert.ok(true), _ => assert.ok(false));
+  });
+});

lighthouse-extension/app/src/popup.js

@@ -131,11 +131,16 @@ document.addEventListener('DOMContentLoaded', _ => {
       }, selectedAudits);
     })
     .catch(err => {
-      let {message} = err;
-      if (err.message.toLowerCase().startsWith('another debugger')) {
+      let message = err.message;
+      if (message.toLowerCase().startsWith('another debugger')) {
         message = 'You probably have DevTools open.' +
           ' Close DevTools to use lighthouse';
       }
+      if (message.toLowerCase().includes('multiple tabs')) {
+        message = 'You probably have multiple tabs open to the same origin.' +
+          ' Close the other tabs to use lighthouse.';
+      }
+
       feedbackEl.textContent = message;
       stopSpinner();
       background.console.error(err);