Fix upload button & shortcut not working for narrow composer mode (#7894)

src/components/views/rooms/MessageComposerButtons.tsx

@@ -70,7 +70,7 @@ const MessageComposerButtons: React.FC<IProps> = (props: IProps) => {
             emojiButton(props),
         ];
         moreButtons = [
-            uploadButton(props, roomId),
+            uploadButton(), // props passed via UploadButtonContext
             showStickersButton(props),
             voiceRecordingButton(props, narrow),
             pollButton(room, props.relation),
@@ -79,7 +79,7 @@ const MessageComposerButtons: React.FC<IProps> = (props: IProps) => {
     } else {
         mainButtons = [
             emojiButton(props),
-            uploadButton(props, roomId),
+            uploadButton(), // props passed via UploadButtonContext
         ];
         moreButtons = [
             showStickersButton(props),
@@ -98,7 +98,7 @@ const MessageComposerButtons: React.FC<IProps> = (props: IProps) => {
         mx_MessageComposer_closeButtonMenu: props.isMenuOpen,
     });
 
-    return <>
+    return <UploadButtonContextProvider roomId={roomId} relation={props.relation}>
         { mainButtons }
         <AccessibleTooltipButton
             className={moreOptionsClasses}
@@ -116,7 +116,7 @@ const MessageComposerButtons: React.FC<IProps> = (props: IProps) => {
                 </OverflowMenuContext.Provider>
             </ContextMenu>
         ) }
-    </>;
+    </UploadButtonContextProvider>;
 };
 
 function emojiButton(props: IProps): ReactElement {
@@ -175,23 +175,22 @@ const EmojiButton: React.FC<IEmojiButtonProps> = ({ addEmoji, menuPosition }) =>
     </React.Fragment>;
 };
 
-function uploadButton(props: IProps, roomId: string): ReactElement {
-    return <UploadButton
-        key="controls_upload"
-        roomId={roomId}
-        relation={props.relation}
-    />;
+function uploadButton(): ReactElement {
+    return <UploadButton key="controls_upload" />;
 }
 
+type UploadButtonFn = () => void;
+export const UploadButtonContext = createContext<UploadButtonFn | null>(null);
+
 interface IUploadButtonProps {
     roomId: string;
     relation?: IEventRelation | null;
 }
 
-const UploadButton = ({ roomId, relation }: IUploadButtonProps) => {
+// We put the file input outside the UploadButton component so that it doesn't get killed when the context menu closes.
+const UploadButtonContextProvider: React.FC<IUploadButtonProps> = ({ roomId, relation, children }) => {
     const cli = useContext(MatrixClientContext);
     const roomContext = useContext(RoomContext);
-    const overflowMenuCloser = useContext(OverflowMenuContext);
     const uploadInput = useRef<HTMLInputElement>();
 
     const onUploadClick = () => {
@@ -200,7 +199,6 @@ const UploadButton = ({ roomId, relation }: IUploadButtonProps) => {
             return;
         }
         uploadInput.current?.click();
-        overflowMenuCloser?.(); // close overflow menu
     };
 
     useDispatcher(dis, payload => {
@@ -229,12 +227,9 @@ const UploadButton = ({ roomId, relation }: IUploadButtonProps) => {
     };
 
     const uploadInputStyle = { display: 'none' };
-    return <>
-        <CollapsibleButton
-            className="mx_MessageComposer_button mx_MessageComposer_upload"
-            onClick={onUploadClick}
-            title={_t('Attachment')}
-        />
+    return <UploadButtonContext.Provider value={onUploadClick}>
+        { children }
+
         <input
             ref={uploadInput}
             type="file"
@@ -242,7 +237,24 @@ const UploadButton = ({ roomId, relation }: IUploadButtonProps) => {
             multiple
             onChange={onUploadFileInputChange}
         />
-    </>;
+    </UploadButtonContext.Provider>;
+};
+
+// Must be rendered within an UploadButtonContextProvider
+const UploadButton = () => {
+    const overflowMenuCloser = useContext(OverflowMenuContext);
+    const uploadButtonFn = useContext(UploadButtonContext);
+
+    const onClick = () => {
+        uploadButtonFn?.();
+        overflowMenuCloser?.(); // close overflow menu
+    };
+
+    return <CollapsibleButton
+        className="mx_MessageComposer_button mx_MessageComposer_upload"
+        onClick={onClick}
+        title={_t('Attachment')}
+    />;
 };
 
 function showStickersButton(props: IProps): ReactElement {