Happily handle empty text messages (#6825)

This commig refactors the message-deletion modal and reuses it for case of removing
the entire message and trying to send it, which should trigger removal flow instead.

Fix vector-im/element-web#18873

src/components/views/context_menus/MessageContextMenu.tsx

@@ -34,8 +34,7 @@ import ForwardDialog from "../dialogs/ForwardDialog";
 import { Action } from "../../../dispatcher/actions";
 import ReportEventDialog from '../dialogs/ReportEventDialog';
 import ViewSource from '../../structures/ViewSource';
-import ConfirmRedactDialog from '../dialogs/ConfirmRedactDialog';
-import ErrorDialog from '../dialogs/ErrorDialog';
+import { createRedactEventDialog } from '../dialogs/ConfirmRedactDialog';
 import ShareDialog from '../dialogs/ShareDialog';
 import { RoomPermalinkCreator } from "../../../utils/permalinks/Permalinks";
 import { IPosition, ChevronFace } from '../../structures/ContextMenu';
@@ -140,34 +139,11 @@ export default class MessageContextMenu extends React.Component<IProps, IState>
     };
 
     private onRedactClick = (): void => {
-        Modal.createTrackedDialog('Confirm Redact Dialog', '', ConfirmRedactDialog, {
-            onFinished: async (proceed: boolean, reason?: string) => {
-                if (!proceed) return;
-
-                const cli = MatrixClientPeg.get();
-                try {
-                    this.props.onCloseDialog?.();
-                    await cli.redactEvent(
-                        this.props.mxEvent.getRoomId(),
-                        this.props.mxEvent.getId(),
-                        undefined,
-                        reason ? { reason } : {},
-                    );
-                } catch (e) {
-                    const code = e.errcode || e.statusCode;
-                    // only show the dialog if failing for something other than a network error
-                    // (e.g. no errcode or statusCode) as in that case the redactions end up in the
-                    // detached queue and we show the room status bar to allow retry
-                    if (typeof code !== "undefined") {
-                        // display error message stating you couldn't delete this.
-                        Modal.createTrackedDialog('You cannot delete this message', '', ErrorDialog, {
-                            title: _t('Error'),
-                            description: _t('You cannot delete this message. (%(code)s)', { code }),
-                        });
-                    }
-                }
-            },
-        }, 'mx_Dialog_confirmredact');
+        const { mxEvent, onCloseDialog } = this.props;
+        createRedactEventDialog({
+            mxEvent,
+            onCloseDialog,
+        });
         this.closeMenu();
     };
 

src/components/views/dialogs/ConfirmRedactDialog.tsx

@@ -14,9 +14,13 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { MatrixEvent } from 'matrix-js-sdk/src/models/event';
 import React from 'react';
 import { _t } from '../../../languageHandler';
+import { MatrixClientPeg } from '../../../MatrixClientPeg';
+import Modal from '../../../Modal';
 import { replaceableComponent } from "../../../utils/replaceableComponent";
+import ErrorDialog from './ErrorDialog';
 import TextInputDialog from "./TextInputDialog";
 
 interface IProps {
@@ -42,3 +46,40 @@ export default class ConfirmRedactDialog extends React.Component<IProps> {
         );
     }
 }
+
+export function createRedactEventDialog({
+    mxEvent,
+    onCloseDialog = () => {},
+}: {
+    mxEvent: MatrixEvent;
+    onCloseDialog?: () => void;
+}) {
+    Modal.createTrackedDialog('Confirm Redact Dialog', '', ConfirmRedactDialog, {
+        onFinished: async (proceed: boolean, reason?: string) => {
+            if (!proceed) return;
+
+            const cli = MatrixClientPeg.get();
+            try {
+                onCloseDialog?.();
+                await cli.redactEvent(
+                    mxEvent.getRoomId(),
+                    mxEvent.getId(),
+                    undefined,
+                    reason ? { reason } : {},
+                );
+            } catch (e) {
+                const code = e.errcode || e.statusCode;
+                // only show the dialog if failing for something other than a network error
+                // (e.g. no errcode or statusCode) as in that case the redactions end up in the
+                // detached queue and we show the room status bar to allow retry
+                if (typeof code !== "undefined") {
+                    // display error message stating you couldn't delete this.
+                    Modal.createTrackedDialog('You cannot delete this message', '', ErrorDialog, {
+                        title: _t('Error'),
+                        description: _t('You cannot delete this message. (%(code)s)', { code }),
+                    });
+                }
+            }
+        },
+    }, 'mx_Dialog_confirmredact');
+}

src/components/views/rooms/EditMessageComposer.tsx

@@ -42,6 +42,7 @@ import ErrorDialog from "../dialogs/ErrorDialog";
 import QuestionDialog from "../dialogs/QuestionDialog";
 import { ActionPayload } from "../../../dispatcher/payloads";
 import AccessibleButton from '../elements/AccessibleButton';
+import { createRedactEventDialog } from '../dialogs/ConfirmRedactDialog';
 import SettingsStore from "../../../settings/SettingsStore";
 
 import { logger } from "matrix-js-sdk/src/logger";
@@ -331,6 +332,14 @@ export default class EditMessageComposer extends React.Component<IProps, IState>
 
         let shouldSend = true;
 
+        if (newContent?.body === '') {
+            this.cancelPreviousPendingEdit();
+            createRedactEventDialog({
+                mxEvent: editedEvent,
+            });
+            return;
+        }
+
         // If content is modified then send an updated event into the room
         if (this.isContentModified(newContent)) {
             const roomId = editedEvent.getRoomId();

src/editor/serialize.ts

@@ -185,7 +185,7 @@ export function startsWith(model: EditorModel, prefix: string, caseSensitive = t
     const firstPart = model.parts[0];
     // part type will be "plain" while editing,
     // and "command" while composing a message.
-    let text = firstPart && firstPart.text;
+    let text = firstPart?.text || '';
     if (!caseSensitive) {
         prefix = prefix.toLowerCase();
         text = text.toLowerCase();