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`

cypress/e2e/settings/hidden-rr-migration.spec.ts

@@ -0,0 +1,90 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/// <reference types="cypress" />
+
+import { SynapseInstance } from "../../plugins/synapsedocker";
+
+function seedLabs(synapse: SynapseInstance, labsVal: boolean | null): void {
+    cy.initTestUser(synapse, "Sally", () => {
+        // seed labs flag
+        cy.window({ log: false }).then(win => {
+            if (typeof labsVal === "boolean") {
+                // stringify boolean
+                win.localStorage.setItem("mx_labs_feature_feature_hidden_read_receipts", `${labsVal}`);
+            }
+        });
+    });
+}
+
+function testForVal(settingVal: boolean | null): void {
+    const testRoomName = "READ RECEIPTS";
+    cy.createRoom({ name: testRoomName }).as("roomId");
+    cy.all([cy.get<string>("@roomId")]).then(() => {
+        cy.viewRoomByName(testRoomName).then(() => {
+            // if we can see the room, then sync is working for us. It's time to see if the
+            // migration even ran.
+
+            cy.getSettingValue("sendReadReceipts", null, true).should("satisfy", (val) => {
+                if (typeof settingVal === "boolean") {
+                    return val === settingVal;
+                } else {
+                    return !val; // falsy - we don't actually care if it's undefined, null, or a literal false
+                }
+            });
+        });
+    });
+}
+
+describe("Hidden Read Receipts Setting Migration", () => {
+    // We run this as a full-blown end-to-end test to ensure it works in an integration
+    // sense. If we unit tested it, we'd be testing that the code works but not that the
+    // migration actually runs.
+    //
+    // Here, we get to test that not only the code works but also that it gets run. Most
+    // of our interactions are with the JS console as we're honestly just checking that
+    // things got set correctly.
+    //
+    // For a security-sensitive feature like hidden read receipts, it's absolutely vital
+    // that we migrate the setting appropriately.
+
+    let synapse: SynapseInstance;
+
+    beforeEach(() => {
+        cy.startSynapse("default").then(data => {
+            synapse = data;
+        });
+    });
+
+    afterEach(() => {
+        cy.stopSynapse(synapse);
+    });
+
+    it('should not migrate the lack of a labs flag', () => {
+        seedLabs(synapse, null);
+        testForVal(null);
+    });
+
+    it('should migrate labsHiddenRR=false as sendRR=true', () => {
+        seedLabs(synapse, false);
+        testForVal(true);
+    });
+
+    it('should migrate labsHiddenRR=true as sendRR=false', () => {
+        seedLabs(synapse, true);
+        testForVal(false);
+    });
+});