fix: check if the instrumentation process stops by sending a request (#…

…655)

* fix: check if the instrumentation process stops by sending a request

* chore: use process existence check instead

* use vanilla axios

* change to warn

* simplify a bit

* Update uiautomator2.js

lib/uiautomator2.js

@@ -305,10 +305,37 @@ class UiAutomator2Server {
   async cleanupAutomationLeftovers (strictCleanup = false) {
     this.log.debug(`Performing ${strictCleanup ? 'strict' : 'shallow'} cleanup of automation leftovers`);
 
+    const axiosTimeout = 500;
+
+    const waitStop = async () => {
+      // Wait for the process stop by sending a status request to the port.
+      // We observed the process stop could be delayed, thus causing unexpected crashes
+      // in the middle of the session preparation process. It caused an invalid session error response
+      // by the uia2 server, but that was because the process stop's delay.
+      const timeout = 3000;
+      try {
+        await waitForCondition(async () => {
+          try {
+            await axios({
+              url: `http://${this.host}:${this.systemPort}/status`,
+              timeout: axiosTimeout,
+            });
+          } catch (err) {
+            return true;
+          }
+        }, {
+          waitMs: timeout,
+          intervalMs: 100,
+        });
+      } catch (err) {
+        this.log.warn(`The ${SERVER_TEST_PACKAGE_ID} process might fail to stop within ${timeout}ms timeout.`);
+      }
+    };
+
     try {
       const {value} = (await axios({
         url: `http://${this.host}:${this.systemPort}/sessions`,
-        timeout: 500,
+        timeout: axiosTimeout,
       })).data;
       const activeSessionIds = value.map(({id}) => id).filter(Boolean);
       if (activeSessionIds.length) {
@@ -329,13 +356,13 @@ class UiAutomator2Server {
     try {
       await this.adb.forceStop(SERVER_TEST_PACKAGE_ID);
     } catch (ignore) {}
-    if (!strictCleanup) {
-      return;
+    if (strictCleanup) {
+      // https://github.com/appium/appium/issues/10749
+      try {
+        await this.adb.killProcessesByName('uiautomator');
+      } catch (ignore) {}
     }
-    // https://github.com/appium/appium/issues/10749
-    try {
-      await this.adb.killProcessesByName('uiautomator');
-    } catch (ignore) {}
+    await waitStop();
   }
 }