Migrate the hidden read receipts flag to new "send read receipts" option (#9141)

* Migrate the hidden read receipts flag to new "send read receipts" option

For safety.

* Appease linter & ignore guests

* `void`

src/settings/SettingsStore.ts

@@ -35,6 +35,9 @@ import SettingsHandler from "./handlers/SettingsHandler";
 import { SettingUpdatedPayload } from "../dispatcher/payloads/SettingUpdatedPayload";
 import { Action } from "../dispatcher/actions";
 import PlatformSettingsHandler from "./handlers/PlatformSettingsHandler";
+import dispatcher from "../dispatcher/dispatcher";
+import { ActionPayload } from "../dispatcher/payloads";
+import { MatrixClientPeg } from "../MatrixClientPeg";
 
 const defaultWatchManager = new WatchManager();
 
@@ -565,6 +568,44 @@ export default class SettingsStore {
         return null;
     }
 
+    /**
+     * Runs or queues any setting migrations needed.
+     */
+    public static runMigrations(): void {
+        // Dev notes: to add your migration, just add a new `migrateMyFeature` function, call it, and
+        // add a comment to note when it can be removed.
+
+        SettingsStore.migrateHiddenReadReceipts(); // Can be removed after October 2022.
+    }
+
+    private static migrateHiddenReadReceipts(): void {
+        if (MatrixClientPeg.get().isGuest()) return; // not worth it
+
+        // We wait for the first sync to ensure that the user's existing account data has loaded, as otherwise
+        // getValue() for an account-level setting like sendReadReceipts will return `null`.
+        const disRef = dispatcher.register((payload: ActionPayload) => {
+            if (payload.action === "MatrixActions.sync") {
+                dispatcher.unregister(disRef);
+
+                const rrVal = SettingsStore.getValue("sendReadReceipts", null, true);
+                if (typeof rrVal !== "boolean") {
+                    // new setting isn't set - see if the labs flag was. We have to manually reach into the
+                    // handler for this because it isn't a setting anymore (`getValue` will yell at us).
+                    const handler = LEVEL_HANDLERS[SettingLevel.DEVICE] as DeviceSettingsHandler;
+                    const labsVal = handler.readFeature("feature_hidden_read_receipts");
+                    if (typeof labsVal === "boolean") {
+                        // Inverse of labs flag because negative->positive language switch in setting name
+                        const newVal = !labsVal;
+                        console.log(`Setting sendReadReceipts to ${newVal} because of previously-set labs flag`);
+
+                        // noinspection JSIgnoredPromiseFromCall
+                        SettingsStore.setValue("sendReadReceipts", null, SettingLevel.ACCOUNT, newVal);
+                    }
+                }
+            }
+        });
+    }
+
     /**
      * Debugging function for reading explicit setting values without going through the
      * complicated/biased functions in the SettingsStore. This will print information to

src/settings/handlers/DeviceSettingsHandler.ts

@@ -114,12 +114,16 @@ export default class DeviceSettingsHandler extends AbstractLocalStorageSettingsH
     // Note: features intentionally don't use the same key as settings to avoid conflicts
     // and to be backwards compatible.
 
-    private readFeature(featureName: string): boolean | null {
+    // public for access to migrations - not exposed from the SettingsHandler interface
+    public readFeature(featureName: string): boolean | null {
         if (MatrixClientPeg.get() && MatrixClientPeg.get().isGuest()) {
             // Guests should not have any labs features enabled.
             return false;
         }
 
+        // XXX: This turns they key names into `mx_labs_feature_feature_x` (double feature).
+        // This is because all feature names start with `feature_` as a matter of policy.
+        // Oh well.
         return this.getBoolean("mx_labs_feature_" + featureName);
     }