Ensure we do not fire the verification mismatch modal multiple times

playwright/e2e/crypto/verification.spec.ts

@@ -240,24 +240,26 @@ test.describe("User verification", () => {
     test.use({
         displayName: "Alice",
         botCreateOpts: { displayName: "Bob", autoAcceptInvites: true, userIdPrefix: "bob_" },
+        room: async ({ page, app, bot: bob, user: aliceCredentials }, use) => {
+            await app.client.bootstrapCrossSigning(aliceCredentials);
+
+            // the other user creates a DM
+            const dmRoomId = await createDMRoom(bob, aliceCredentials.userId);
+
+            // accept the DM
+            await app.viewRoomByName("Bob");
+            await page.getByRole("button", { name: "Start chatting" }).click();
+            await use({ roomId: dmRoomId });
+        },
     });
 
     test("can receive a verification request when there is no existing DM", async ({
         page,
-        app,
         bot: bob,
         user: aliceCredentials,
         toasts,
+        room: { roomId: dmRoomId },
     }) => {
-        await app.client.bootstrapCrossSigning(aliceCredentials);
-
-        // the other user creates a DM
-        const dmRoomId = await createDMRoom(bob, aliceCredentials.userId);
-
-        // accept the DM
-        await app.viewRoomByName("Bob");
-        await page.getByRole("button", { name: "Start chatting" }).click();
-
         // once Alice has joined, Bob starts the verification
         const bobVerificationRequest = await bob.evaluateHandle(
             async (client, { dmRoomId, aliceCredentials }) => {
@@ -294,6 +296,51 @@ test.describe("User verification", () => {
         await expect(page.getByText("You've successfully verified Bob!")).toBeVisible();
         await page.getByRole("button", { name: "Got it" }).click();
     });
+
+    test("can abort emoji verification when emoji mismatch", async ({
+        page,
+        bot: bob,
+        user: aliceCredentials,
+        toasts,
+        room: { roomId: dmRoomId },
+        cryptoBackend,
+    }) => {
+        test.skip(cryptoBackend === "legacy", "Not implemented for legacy crypto");
+
+        // once Alice has joined, Bob starts the verification
+        const bobVerificationRequest = await bob.evaluateHandle(
+            async (client, { dmRoomId, aliceCredentials }) => {
+                const room = client.getRoom(dmRoomId);
+                while (room.getMember(aliceCredentials.userId)?.membership !== "join") {
+                    await new Promise((resolve) => {
+                        room.once(window.matrixcs.RoomStateEvent.Members, resolve);
+                    });
+                }
+
+                return client.getCrypto().requestVerificationDM(aliceCredentials.userId, dmRoomId);
+            },
+            { dmRoomId, aliceCredentials },
+        );
+
+        // Accept verification via toast
+        const toast = await toasts.getToast("Verification requested");
+        await toast.getByRole("button", { name: "Verify Session" }).click();
+
+        // request verification by emoji
+        await page.locator("#mx_RightPanel").getByRole("button", { name: "Verify by emoji" }).click();
+
+        /* on the bot side, wait for the verifier to exist ... */
+        const botVerifier = await awaitVerifier(bobVerificationRequest);
+        // ... confirm ...
+        botVerifier.evaluate((verifier) => verifier.verify()).catch(() => {});
+        // ... and abort the verification
+        await page.getByRole("button", { name: "They don't match" }).click();
+
+        const dialog = page.locator(".mx_Dialog");
+        await expect(dialog.getByText("Your messages are not secure")).toBeVisible();
+        await dialog.getByRole("button", { name: "OK" }).click();
+        await expect(dialog).not.toBeVisible();
+    });
 });
 
 /** Extract the qrcode out of an on-screen html element */

src/components/views/right_panel/EncryptionPanel.tsx

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { useCallback, useEffect, useState } from "react";
+import React, { useCallback, useEffect, useRef, useState } from "react";
 import { VerificationPhase, VerificationRequest, VerificationRequestEvent } from "matrix-js-sdk/src/crypto-api";
 import { RoomMember, User } from "matrix-js-sdk/src/matrix";
 
@@ -69,13 +69,17 @@ const EncryptionPanel: React.FC<IProps> = (props: IProps) => {
             awaitPromise();
         }
     }, [verificationRequestPromise]);
+    // Use a ref to track whether we are already showing the mismatch modal as state may not update fast enough
+    // if two change events are fired in quick succession like can happen with rust crypto.
+    const isShowingMismatchModal = useRef(false);
     const changeHandler = useCallback(() => {
         // handle transitions -> cancelled for mismatches which fire a modal instead of showing a card
         if (
-            request &&
-            request.phase === VerificationPhase.Cancelled &&
+            !isShowingMismatchModal.current &&
+            request?.phase === VerificationPhase.Cancelled &&
             MISMATCHES.includes(request.cancellationCode ?? "")
         ) {
+            isShowingMismatchModal.current = true;
             Modal.createDialog(ErrorDialog, {
                 headerImage: require("../../../../res/img/e2e/warning-deprecated.svg").default,
                 title: _t("encryption|messages_not_secure|title"),