fix: Start page status monitoring on page change event as well (#402)

lib/mixins/navigate.js

@@ -1,4 +1,4 @@
-import { checkParams } from '../utils';
+import { checkParams, pageArrayFromDict } from '../utils';
 import events from './events';
 import { timing, util } from '@appium/support';
 import _ from 'lodash';
@@ -173,10 +173,9 @@ export async function checkPageIsReady (timeoutMs) {
  * @returns {Promise<void>}
  */
 export async function navToUrl (url) {
-  checkParams({
-    appIdKey: getAppIdKey(this),
-    pageIdKey: getPageIdKey(this),
-  });
+  const appIdKey = getAppIdKey(this);
+  const pageIdKey = getPageIdKey(this);
+  checkParams({appIdKey, pageIdKey});
   const rpcClient = this.requireRpcClient();
 
   try {
@@ -191,17 +190,37 @@ export async function navToUrl (url) {
   /** @type {(() => void)|undefined} */
   let onPageLoaded;
   /** @type {(() => void)|undefined} */
+  let onPageChanged;
+  /** @type {(() => void)|undefined} */
   let onTargetProvisioned;
   /** @type {NodeJS.Timeout|undefined|null} */
   let onPageLoadedTimeout;
   setPageLoadDelay(this, util.cancellableDelay(readinessTimeoutMs));
   setPageLoading(this, true);
   let isPageLoading = true;
   let didPageFinishLoad = false;
+  /** @type {Promise<void>|null} */
+  let pageReadinessCheckPromise = null;
   const start = new timing.Timer().start();
 
   /** @type {B<void>} */
   const pageReadinessPromise = new B((resolve) => {
+    const performPageReadinessCheck = async () => {
+      while (isPageLoading) {
+        const pageReadyCheckStart = new timing.Timer().start();
+        try {
+          const isReady = await this.checkPageIsReady(PAGE_READINESS_JS_MIN_CHECK_INTERVAL_MS);
+          if (isReady && isPageLoading && onPageLoaded) {
+            return onPageLoaded();
+          }
+        } catch (ign) {}
+        const msLeft = PAGE_READINESS_JS_MIN_CHECK_INTERVAL_MS - pageReadyCheckStart.getDuration().asMilliSeconds;
+        if (msLeft > 0 && isPageLoading) {
+          await B.delay(msLeft);
+        }
+      }
+    };
+
     onPageLoadedTimeout = setTimeout(() => {
       if (isPageLoading) {
         isPageLoading = false;
@@ -225,33 +244,55 @@ export async function navToUrl (url) {
       didPageFinishLoad = true;
       return resolve();
     };
+
+    // Sometimes it could be observed that we do not receive
+    // any events for target provisioning while navigating to a new page,
+    // but only events related to the page change.
+    // So lets just start the monitoring loop as soon as any of these events arrives
+    // for the target page.
+    onPageChanged = async (
+      /** @type {Error|null} */ err,
+      /** @type {string} */ _appIdKey,
+      /** @type {import("@appium/types").StringRecord} */ pageDict
+    ) => {
+      if (_appIdKey !== appIdKey) {
+        return;
+      }
+
+      /** @type {import('../types').Page|undefined} */
+      const targetPage = pageArrayFromDict(pageDict)
+        .find(({id}) => parseInt(`${id}`, 10) === parseInt(`${pageIdKey}`, 10));
+      if (targetPage?.url === url) {
+        this.log.debug(`The page ${targetPage.id} got a new URL ${url}`);
+        if (pageReadinessCheckPromise) {
+          this.log.debug('Page readiness monitoring is already running');
+        } else {
+          this.log.debug('Monitoring its readiness');
+          pageReadinessCheckPromise = performPageReadinessCheck();
+          await pageReadinessCheckPromise;
+        }
+      }
+    };
+    rpcClient.on('_rpc_forwardGetListing:', onPageChanged);
+
     // https://chromedevtools.github.io/devtools-protocol/tot/Page/#event-loadEventFired
     rpcClient.once('Page.loadEventFired', onPageLoaded);
-    // Pages that have no proper DOM structure do not fire the `Page.loadEventFired` event
-    // so we rely on the very first event after target change, which is `onTargetProvisioned`
-    // and start sending `document.readyState` requests until we either succeed or
-    // another event/timeout happens
     onTargetProvisioned = async () => {
-      while (isPageLoading) {
-        const pageReadyCheckStart = new timing.Timer().start();
-        try {
-          const isReady = await this.checkPageIsReady(PAGE_READINESS_JS_MIN_CHECK_INTERVAL_MS);
-          if (isReady && isPageLoading && onPageLoaded) {
-            return onPageLoaded();
-          }
-        } catch (ign) {}
-        const msLeft = PAGE_READINESS_JS_MIN_CHECK_INTERVAL_MS - pageReadyCheckStart.getDuration().asMilliSeconds;
-        if (msLeft > 0 && isPageLoading) {
-          await B.delay(msLeft);
-        }
+      this.log.debug('The page target has been provisioned');
+      if (pageReadinessCheckPromise) {
+        this.log.debug('Page readiness monitoring is already running');
+      } else {
+        this.log.debug('Monitoring its readiness');
+        pageReadinessCheckPromise = performPageReadinessCheck();
+        await pageReadinessCheckPromise;
       }
     };
     rpcClient.targetSubscriptions.once(rpcConstants.ON_TARGET_PROVISIONED_EVENT, onTargetProvisioned);
 
     rpcClient.send('Page.navigate', {
       url,
-      appIdKey: getAppIdKey(this),
-      pageIdKey: getPageIdKey(this),
+      appIdKey,
+      pageIdKey,
     });
   });
   /** @type {B<void>} */
@@ -278,6 +319,9 @@ export async function navToUrl (url) {
     if (onPageLoaded) {
       rpcClient.off('Page.loadEventFired', onPageLoaded);
     }
+    if (onPageChanged) {
+      rpcClient.off('_rpc_forwardGetListing:', onPageChanged);
+    }
   }
 
   // enable console logging, so we get the events (otherwise we only