Add thread information in pinned message list

res/css/views/rooms/_PinnedEventTile.pcss

@@ -37,5 +37,28 @@ limitations under the License.
                 white-space: nowrap;
             }
         }
+
+        .mx_PinnedEventTile_thread {
+            display: flex;
+            gap: var(--cpd-space-2x);
+            font: var(--cpd-font-body-sm-regular);
+
+            svg {
+                width: 20px;
+                fill: var(--cpd-color-icon-tertiary);
+            }
+
+            span {
+                display: flex;
+                color: var(--cpd-color-text-secondary);
+            }
+
+            button {
+                background: transparent;
+                border: none;
+                cursor: pointer;
+                text-decoration: underline;
+            }
+        }
     }
 }

src/components/views/rooms/PinnedEventTile.tsx

@@ -23,6 +23,7 @@ import { Icon as UnpinIcon } from "@vector-im/compound-design-tokens/icons/unpin
 import { Icon as ForwardIcon } from "@vector-im/compound-design-tokens/icons/forward.svg";
 import { Icon as TriggerIcon } from "@vector-im/compound-design-tokens/icons/overflow-horizontal.svg";
 import { Icon as DeleteIcon } from "@vector-im/compound-design-tokens/icons/delete.svg";
+import { Icon as ThreadIcon } from "@vector-im/compound-design-tokens/icons/threads.svg";
 import classNames from "classnames";
 
 import dis from "../../../dispatcher/dispatcher";
@@ -39,6 +40,7 @@ import { isContentActionable } from "../../../utils/EventUtils";
 import { getForwardableEvent } from "../../../events";
 import { OpenForwardDialogPayload } from "../../../dispatcher/payloads/OpenForwardDialogPayload";
 import { createRedactEventDialog } from "../dialogs/ConfirmRedactDialog";
+import { ShowThreadPayload } from "../../../dispatcher/payloads/ShowThreadPayload";
 
 const AVATAR_SIZE = "32px";
 
@@ -69,6 +71,9 @@ export function PinnedEventTile({ event, room, permalinkCreator }: PinnedEventTi
         throw new Error("Pinned event unexpectedly has no sender");
     }
 
+    const isInThread = Boolean(event.threadRootId);
+    const displayThreadInfo = !event.isThreadRoot && isInThread;
+
     return (
         <div className="mx_PinnedEventTile" role="listitem">
             <div>
@@ -97,6 +102,36 @@ export function PinnedEventTile({ event, room, permalinkCreator }: PinnedEventTi
                     permalinkCreator={permalinkCreator}
                     replacingEventId={event.replacingEventId()}
                 />
+                {displayThreadInfo && (
+                    <div className="mx_PinnedEventTile_thread">
+                        <ThreadIcon />
+                        {_t(
+                            "right_panel|pinned_messages|reply_thread",
+                            {},
+                            {
+                                link: (sub) => (
+                                    <button
+                                        type="button"
+                                        onClick={() => {
+                                            if (!event.threadRootId) return;
+
+                                            const rootEvent = room.findEventById(event.threadRootId);
+                                            if (!rootEvent) return;
+
+                                            dis.dispatch<ShowThreadPayload>({
+                                                action: Action.ShowThread,
+                                                rootEvent: rootEvent,
+                                                push: true,
+                                            });
+                                        }}
+                                    >
+                                        {sub}
+                                    </button>
+                                ),
+                            },
+                        )}
+                    </div>
+                )}
             </div>
         </div>
     );

src/i18n/strings/en_EN.json

@@ -1850,6 +1850,7 @@
                 "other": "You can only pin up to %(count)s widgets"
             },
             "menu": "Open menu",
+            "reply_thread": "Reply to a <link>thread message</link>",
             "title": "Pinned messages",
             "unpin_all": {
                 "button": "Unpin all messages",

test/components/views/rooms/PinnedEventTile-test.tsx

@@ -97,6 +97,36 @@ describe("<PinnedEventTile />", () => {
         expect(container).toMatchSnapshot();
     });
 
+    it("should render pinned event with thread info", async () => {
+        const event = makePinEvent({
+            content: {
+                "body": "First pinned message",
+                "msgtype": "m.text",
+                "m.relates_to": {
+                    "event_id": "$threadRootEventId",
+                    "is_falling_back": true,
+                    "m.in_reply_to": {
+                        event_id: "$$threadRootEventId",
+                    },
+                    "rel_type": "m.thread",
+                },
+            },
+        });
+        const threadRootEvent = makePinEvent({ event_id: "$threadRootEventId" });
+        jest.spyOn(room, "findEventById").mockReturnValue(threadRootEvent);
+
+        const { container } = renderComponent(event);
+        expect(container).toMatchSnapshot();
+
+        await userEvent.click(screen.getByRole("button", { name: "thread message" }));
+        // Check that the thread is opened
+        expect(dis.dispatch).toHaveBeenCalledWith({
+            action: Action.ShowThread,
+            rootEvent: threadRootEvent,
+            push: true,
+        });
+    });
+
     it("should render the menu without unpin and delete", async () => {
         jest.spyOn(room.getLiveTimeline().getState(EventTimeline.FORWARDS)!, "mayClientSendStateEvent").mockReturnValue(
             false,

test/components/views/rooms/__snapshots__/PinnedEventTile-test.tsx.snap

@@ -65,10 +65,88 @@ exports[`<PinnedEventTile /> should render pinned event 1`] = `
 </div>
 `;
 
+exports[`<PinnedEventTile /> should render pinned event with thread info 1`] = `
+<div>
+  <div
+    class="mx_PinnedEventTile"
+    role="listitem"
+  >
+    <div>
+      <span
+        class="_avatar_mcap2_17 mx_BaseAvatar mx_PinnedEventTile_senderAvatar _avatar-imageless_mcap2_61"
+        data-color="2"
+        data-testid="avatar-img"
+        data-type="round"
+        role="presentation"
+        style="--cpd-avatar-size: 32px;"
+      >
+        a
+      </span>
+    </div>
+    <div
+      class="mx_PinnedEventTile_wrapper"
+    >
+      <div
+        class="mx_PinnedEventTile_top"
+      >
+        <span
+          class="_typography_yh5dq_162 _font-body-md-semibold_yh5dq_64 mx_PinnedEventTile_sender mx_Username_color2"
+        >
+          @alice:server.org
+        </span>
+        <button
+          aria-disabled="false"
+          aria-expanded="false"
+          aria-haspopup="menu"
+          aria-label="Open menu"
+          class="_icon-button_bh2qc_17"
+          data-state="closed"
+          id="radix-2"
+          role="button"
+          style="--cpd-icon-button-size: 24px;"
+          tabindex="0"
+          type="button"
+        >
+          <div
+            class="_indicator-icon_133tf_26"
+            style="--cpd-icon-button-size: 100%;"
+          >
+            <div />
+          </div>
+        </button>
+      </div>
+      <div
+        class="mx_MTextBody mx_EventTile_content"
+      >
+        <div
+          class="mx_EventTile_body translate"
+          dir="auto"
+        >
+          First pinned message
+        </div>
+      </div>
+      <div
+        class="mx_PinnedEventTile_thread"
+      >
+        <div />
+        <span>
+          Reply to a 
+          <button
+            type="button"
+          >
+            thread message
+          </button>
+        </span>
+      </div>
+    </div>
+  </div>
+</div>
+`;
+
 exports[`<PinnedEventTile /> should render the menu with all the options 1`] = `
 <div
   aria-label="Open menu"
-  aria-labelledby="radix-6"
+  aria-labelledby="radix-8"
   aria-orientation="vertical"
   class="_menu_1x5h1_17"
   data-align="start"
@@ -77,7 +155,7 @@ exports[`<PinnedEventTile /> should render the menu with all the options 1`] = `
   data-side="right"
   data-state="open"
   dir="ltr"
-  id="radix-7"
+  id="radix-9"
   role="menu"
   style="outline: none; --radix-dropdown-menu-content-transform-origin: var(--radix-popper-transform-origin); --radix-dropdown-menu-content-available-width: var(--radix-popper-available-width); --radix-dropdown-menu-content-available-height: var(--radix-popper-available-height); --radix-dropdown-menu-trigger-width: var(--radix-popper-anchor-width); --radix-dropdown-menu-trigger-height: var(--radix-popper-anchor-height); pointer-events: auto;"
   tabindex="-1"
@@ -226,7 +304,7 @@ exports[`<PinnedEventTile /> should render the menu with all the options 1`] = `
 exports[`<PinnedEventTile /> should render the menu without unpin and delete 1`] = `
 <div
   aria-label="Open menu"
-  aria-labelledby="radix-2"
+  aria-labelledby="radix-4"
   aria-orientation="vertical"
   class="_menu_1x5h1_17"
   data-align="start"
@@ -235,7 +313,7 @@ exports[`<PinnedEventTile /> should render the menu without unpin and delete 1`]
   data-side="right"
   data-state="open"
   dir="ltr"
-  id="radix-3"
+  id="radix-5"
   role="menu"
   style="outline: none; --radix-dropdown-menu-content-transform-origin: var(--radix-popper-transform-origin); --radix-dropdown-menu-content-available-width: var(--radix-popper-available-width); --radix-dropdown-menu-content-available-height: var(--radix-popper-available-height); --radix-dropdown-menu-trigger-width: var(--radix-popper-anchor-width); --radix-dropdown-menu-trigger-height: var(--radix-popper-anchor-height); pointer-events: auto;"
   tabindex="-1"