Await download status report before resolving download() (#16)

Previously reportStatusDownload was fire-and-forget: download() resolved
as soon as the native download finished, without waiting for the
report_status/download HTTP call to complete. This let install() (and
a potential immediate-mode reload) run ahead of the report, so if the
app reloaded or was killed first, the download report was silently lost.

Now the report is awaited, with errors caught locally so a failed
report never blocks or breaks the install flow. This adds a small
delay to download() resolving, which is an acceptable tradeoff since
most installs are backgrounded, and even in immediate mode the wait
is dominated by the download itself.

Also adds a clarifying comment to reportStatusDeploy noting that
deployedPackage/status are null for the binary-update report case.

Author: ofalvai

package-mixins.js

@@ -1,6 +1,23 @@
 import { NativeEventEmitter } from "react-native";
 import log from "./logging";
 
+// Reporting this event is important, but avoid blocking install()/restartApp() indefinitely
+// on a stalled network request.
+const REPORT_STATUS_DOWNLOAD_TIMEOUT_MS = 5000;
+
+async function withTimeout(promise, timeoutMs) {
+  let timer;
+  const timeout = new Promise((_, reject) => {
+    timer = setTimeout(() => reject(new Error(`Timed out after ${timeoutMs}ms`)), timeoutMs);
+  });
+
+  try {
+    return await Promise.race([promise, timeout]);
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
 // This function is used to augment remote and local
 // package objects with additional functionality/properties
 // beyond what is included in the metadata sent by the server.
@@ -31,10 +48,11 @@ module.exports = (NativeCodePush) => {
           const downloadedPackage = await NativeCodePush.downloadUpdate(updatePackageCopy, !!downloadProgressCallback);
 
           if (reportStatusDownload) {
-            reportStatusDownload(this)
-            .catch((err) => {
+            try {
+              await withTimeout(reportStatusDownload(this), REPORT_STATUS_DOWNLOAD_TIMEOUT_MS);
+            } catch (err) {
               log(`Report download status failed: ${err}`);
-            });
+            }
           }
 
           return { ...downloadedPackage, ...local };
@@ -65,4 +83,4 @@ module.exports = (NativeCodePush) => {
   };
 
   return { local, remote };
-};
+};

src/acquisition-sdk/acquisition-sdk.ts

@@ -166,6 +166,7 @@ export class AcquisitionManager {
         });
     }
 
+    // Note: deployedPackage and status are null when reporting a "binary update" (i.e. the app was updated through the app store, not CodePush)
     public reportStatusDeploy(deployedPackage?: Package, status?: string, previousLabelOrAppVersion?: string, previousDeploymentKey?: string, callback?: Callback<void>): void {
         if (AcquisitionManager._apiCallsDisabled) {
             console.log(`[CodePush] Api calls are disabled, skipping API call`);
@@ -289,4 +290,4 @@ function queryStringify(object: Object): string {
     }
 
     return queryString;
-}
+}