Method _mount_message

libs/code/deepagents_code/app.py:11045–11145

Mount a message widget to the messages area. This method also stores the message data and handles pruning when the widget count exceeds the maximum. If the `#messages` container is not present (e.g. the screen has been torn down during an interruption), the call is

(
        self,
        widget: Static | AssistantMessage | ToolCallMessage | SkillMessage,
    )

            )

    async def _mount_message(
        self,
        widget: Static | AssistantMessage | ToolCallMessage | SkillMessage,
    ) -> None:
        """Mount a message widget to the messages area.

        This method also stores the message data and handles pruning
        when the widget count exceeds the maximum.

        If the `#messages` container is not present (e.g. the screen has
        been torn down during an interruption), the call is silently skipped
        to avoid cascading `NoMatches` errors.

        Args:
            widget: The message widget to mount
        """
        try:
            messages = self.query_one("#messages", Container)
        except NoMatches:
            return

        # During shutdown (e.g. Ctrl+D mid-stream) the container may still
        # be in the DOM tree but already detached, so mount() would raise
        # MountError. Bail out silently — the app is exiting anyway.
        if not messages.is_attached:
            return

        if isinstance(widget, QueuedUserMessage):
            # Queued placeholders mount at the bottom and stay out of the
            # message store; drain remounts them as real UserMessage widgets.
            await messages.mount(widget)
            try:
                input_container = self.query_one("#bottom-app-container", Container)
                input_container.scroll_visible()
            except NoMatches:
                pass
            return

        # Eagerly fold tool calls into a single live summary so they are
        # collapsed from the moment they start, rather than rendering verbose
        # then snapping shut. A groupable tool joins (or opens) the current
        # step's group; a diff folds into it; anything else is a step boundary
        # that closes the group.
        is_groupable_tool = (
            isinstance(widget, ToolCallMessage) and widget.tool_name != "ask_user"
        )
        is_diff = isinstance(widget, DiffMessage)

        # Store message data for virtualization
        message_data = MessageData.from_widget(widget)
        if not widget.id:
            # Keep the widget DOM id == store id so pruning can locate a
            # mounted widget (and its timestamp footer) from its MessageData.
            widget.id = message_data.id
        footer = self._build_message_timestamp_footer(
            message_data, visible=self._message_timestamps_visible
        )