Polls: show warning about undecryptable relations

src/components/views/messages/MPollBody.tsx

@@ -182,12 +182,14 @@ export default class MPollBody extends React.Component<IBodyProps, IState> {
     private addListeners(): void {
         this.state.poll?.on(PollEvent.Responses, this.onResponsesChange);
         this.state.poll?.on(PollEvent.End, this.onRelationsChange);
+        this.state.poll?.on(PollEvent.UndecryptableRelations, this.render.bind(this));
     }
 
     private removeListeners(): void {
         if (this.state.poll) {
             this.state.poll.off(PollEvent.Responses, this.onResponsesChange);
             this.state.poll.off(PollEvent.End, this.onRelationsChange);
+            this.state.poll.off(PollEvent.UndecryptableRelations, this.render.bind(this));
         }
     }
 
@@ -297,7 +299,9 @@ export default class MPollBody extends React.Component<IBodyProps, IState> {
         const showResults = poll.isEnded || (disclosed && myVote !== undefined);
 
         let totalText: string;
-        if (poll.isEnded) {
+        if (showResults && poll.undecryptableRelationsCount) {
+            totalText = _t("Due to decryption errors, some votes may not be counted");
+        } else if (poll.isEnded) {
             totalText = _t("Final result based on %(count)s votes", { count: totalVotes });
         } else if (!disclosed) {
             totalText = _t("Results will be visible when the poll is ended");

src/i18n/strings/en_EN.json

@@ -2412,6 +2412,7 @@
     "Sorry, you can't edit a poll after votes have been cast.": "Sorry, you can't edit a poll after votes have been cast.",
     "Vote not registered": "Vote not registered",
     "Sorry, your vote was not registered. Please try again.": "Sorry, your vote was not registered. Please try again.",
+    "Due to decryption errors, some votes may not be counted": "Due to decryption errors, some votes may not be counted",
     "Final result based on %(count)s votes|other": "Final result based on %(count)s votes",
     "Final result based on %(count)s votes|one": "Final result based on %(count)s vote",
     "Results will be visible when the poll is ended": "Results will be visible when the poll is ended",

src/utils/poll/countPollDecryptionFailures.ts

@@ -0,0 +1,20 @@
+/*
+Copyright 2023 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.
+*/
+
+import { Relations } from "matrix-js-sdk/src/models/relations";
+
+export const countPollDecryptionFailures = (responseRelations: Relations): number =>
+    responseRelations.getRelations().filter((relationEvent) => relationEvent.isDecryptionFailure()).length;

test/components/views/messages/MPollBody-test.tsx

@@ -765,6 +765,20 @@ describe("MPollBody", () => {
         expect(container).toMatchSnapshot();
     });
 
+    it("renders a warning message when poll has undecryptable relations", async () => {
+        const votes = [
+            responseEvent("@op:example.com", "pizza", 12),
+            responseEvent("@op:example.com", [], 13),
+            responseEvent("@op:example.com", "italian", 14),
+            responseEvent("@me:example.com", "wings", 15),
+            responseEvent("@qr:example.com", "italian", 16),
+        ];
+
+        jest.spyOn(votes[1], "isDecryptionFailure").mockReturnValue(true);
+        const { getByText } = await newMPollBody(votes);
+        expect(getByText("Due to decryption errors, some votes may not be counted")).toBeInTheDocument();
+    });
+
     it("renders a poll with local, non-local and invalid votes", async () => {
         const votes = [
             responseEvent("@a:example.com", "pizza", 12),