Fix pillification sometimes doubling up (#9152)

* Fix pillification sometimes doubling up

* Remove redundant assignment

* Add unit tests around pillification

* Kill ts-ignore

src/utils/pillify.tsx

@@ -44,8 +44,8 @@ export function pillifyLinks(nodes: ArrayLike<Element>, mxEvent: MatrixEvent, pi
     while (node) {
         let pillified = false;
 
-        if (node.tagName === "PRE" || node.tagName === "CODE") {
-            // Skip code blocks
+        if (node.tagName === "PRE" || node.tagName === "CODE" || pills.includes(node)) {
+            // Skip code blocks and existing pills
             node = node.nextSibling as Element;
             continue;
         } else if (node.tagName === "A" && node.getAttribute("href")) {

test/utils/pillify-test.tsx

@@ -0,0 +1,93 @@
+/*
+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.
+*/
+
+import React from "react";
+import { render } from "@testing-library/react";
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+import { ConditionKind, EventType, PushRuleActionName, Room, TweakName } from "matrix-js-sdk/src/matrix";
+
+import { pillifyLinks } from "../../src/utils/pillify";
+import { stubClient } from "../test-utils";
+import { MatrixClientPeg } from "../../src/MatrixClientPeg";
+import DMRoomMap from "../../src/utils/DMRoomMap";
+
+describe("pillify", () => {
+    const roomId = "!room:id";
+    const event = new MatrixEvent({
+        room_id: roomId,
+        type: EventType.RoomMessage,
+        content: {
+            body: "@room",
+        },
+    });
+
+    beforeEach(() => {
+        stubClient();
+        const cli = MatrixClientPeg.get();
+        (cli.getRoom as jest.Mock).mockReturnValue(new Room(roomId, cli, cli.getUserId()));
+        cli.pushRules.global = {
+            override: [
+                {
+                    rule_id: ".m.rule.roomnotif",
+                    default: true,
+                    enabled: true,
+                    conditions: [{
+                        kind: ConditionKind.EventMatch,
+                        key: "content.body",
+                        pattern: "@room",
+                    }],
+                    actions: [
+                        PushRuleActionName.Notify,
+                        {
+                            set_tweak: TweakName.Highlight,
+                            value: true,
+                        },
+                    ],
+                },
+            ],
+        };
+
+        DMRoomMap.makeShared();
+    });
+
+    it("should do nothing for empty element", () => {
+        const { container } = render(<div />);
+        const originalHtml = container.outerHTML;
+        const containers: Element[] = [];
+        pillifyLinks([container], event, containers);
+        expect(containers).toHaveLength(0);
+        expect(container.outerHTML).toEqual(originalHtml);
+    });
+
+    it("should pillify @room", () => {
+        const { container } = render(<div>@room</div>);
+        const containers: Element[] = [];
+        pillifyLinks([container], event, containers);
+        expect(containers).toHaveLength(1);
+        expect(container.querySelector(".mx_Pill.mx_AtRoomPill").textContent).toBe("!@room");
+    });
+
+    it("should not double up pillification on repeated calls", () => {
+        const { container } = render(<div>@room</div>);
+        const containers: Element[] = [];
+        pillifyLinks([container], event, containers);
+        pillifyLinks([container], event, containers);
+        pillifyLinks([container], event, containers);
+        pillifyLinks([container], event, containers);
+        expect(containers).toHaveLength(1);
+        expect(container.querySelector(".mx_Pill.mx_AtRoomPill").textContent).toBe("!@room");
+    });
+});