Fix editing of non-html replies (#8418)

src/editor/deserialize.ts

@@ -16,12 +16,14 @@ limitations under the License.
 */
 
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+import { MsgType } from "matrix-js-sdk/src/@types/event";
 
 import { checkBlockNode } from "../HtmlUtils";
 import { getPrimaryPermalinkEntity } from "../utils/permalinks/Permalinks";
 import { Part, PartCreator, Type } from "./parts";
 import SdkConfig from "../SdkConfig";
 import { textToHtmlRainbow } from "../utils/colour";
+import { stripPlainReply } from "../utils/Reply";
 
 const LIST_TYPES = ["UL", "OL", "LI"];
 
@@ -288,7 +290,7 @@ export function parsePlainTextMessage(
 export function parseEvent(event: MatrixEvent, pc: PartCreator, opts: IParseOptions = { shouldEscape: true }) {
     const content = event.getContent();
     let parts: Part[];
-    const isEmote = content.msgtype === "m.emote";
+    const isEmote = content.msgtype === MsgType.Emote;
     let isRainbow = false;
 
     if (content.format === "org.matrix.custom.html") {
@@ -297,7 +299,11 @@ export function parseEvent(event: MatrixEvent, pc: PartCreator, opts: IParseOpti
             isRainbow = true;
         }
     } else {
-        parts = parsePlainTextMessage(content.body || "", pc, opts);
+        let body = content.body || "";
+        if (event.replyEventId) {
+            body = stripPlainReply(body);
+        }
+        parts = parsePlainTextMessage(body, pc, opts);
     }
 
     if (isEmote && isRainbow) {

test/editor/deserialize-test.ts

@@ -20,7 +20,7 @@ import { createPartCreator } from "./mock";
 
 const FOUR_SPACES = " ".repeat(4);
 
-function htmlMessage(formattedBody, msgtype = "m.text") {
+function htmlMessage(formattedBody: string, msgtype = "m.text") {
     return {
         getContent() {
             return {
@@ -32,7 +32,7 @@ function htmlMessage(formattedBody, msgtype = "m.text") {
     } as unknown as MatrixEvent;
 }
 
-function textMessage(body, msgtype = "m.text") {
+function textMessage(body: string, msgtype = "m.text") {
     return {
         getContent() {
             return {
@@ -43,6 +43,13 @@ function textMessage(body, msgtype = "m.text") {
     } as unknown as MatrixEvent;
 }
 
+function textMessageReply(body: string, msgtype = "m.text") {
+    return {
+        ...textMessage(body, msgtype),
+        replyEventId: "!foo:bar",
+    } as unknown as MatrixEvent;
+}
+
 function mergeAdjacentParts(parts) {
     let prevPart;
     for (let i = 0; i < parts.length; ++i) {
@@ -404,5 +411,14 @@ describe('editor/deserialize', function() {
                 text: "> <del>no formatting here</del>",
             });
         });
+        it("it strips plaintext replies", () => {
+            const body = "> Sender: foo\n\nMessage";
+            const parts = normalize(parseEvent(textMessageReply(body), createPartCreator(), { shouldEscape: false }));
+            expect(parts.length).toBe(1);
+            expect(parts[0]).toStrictEqual({
+                type: "plain",
+                text: "Message",
+            });
+        });
     });
 });