Week 3 on Merkuro (GSoC 2025)

Sunday, 22 June 2025  |  Pablo Ariño

Tackling the Migration Agent

For week three, I finished resolving the configuration window issue for the EteSync resource by hiding the default configuration window and programmatically linking the wizard’s “Accepted” and “Rejected” states to the configuration window’s accept() and reject() methods. This ensured that the wizard cleanly replaced the built-in dialog without leaving a “zombie” window behind. I’ve submitted a merge request for these changes so it can be reviewed and integrated upstream.

With that resolved, I moved on to a new and intriguing component: the PIM Migration Agent. This agent is responsible for managing data migrations between different Akonadi versions or formats — a critical part of ensuring smooth transitions when updating KDE PIM components.

And like the other agents and resources, it was time for it to shed its QtWidgets dependency.

Decoupling the UI

Following the established pattern, I began by:

  • Creating a dedicated UI plugin for the migration agent’s configuration dialog

  • Removing the old configure() method from the agent’s core logic

  • Updating the relevant CMakeLists.txt files to support the plugin and cleanly separate UI code from the core agent

However, while this transition was relatively smooth, the plugin-agent communication needed more work to function correctly in this new structure.

Creating a D-Bus Interface for Plugin-Agent Communication

To enable proper communication between the configuration plugin and the migration agent, I created a new D-Bus interface:
org.kde.Akonadi.MigrationAgent

This interface allows the plugin to:

  • Receive status or configuration information from the agent

  • Send information back if needed (e.g., configuration changes)

To support this, I also:

  • Modified the CMakeLists.txt to include the interface and generate the corresponding D-Bus adaptor

  • Updated both the migrationagent and migrationstatuswidget files to use the new D-Bus interface for interaction

This ensures the plugin can communicate cleanly with the agent without relying on any hard-coded QtWidgets calls or tightly coupled logic.

The KUiServerJobTracker Problem (Still Pending)

While working on the migration agent, I encountered a significant QtWidget dependency:
KUiServerJobTracker, which handles job progress display by showing dialogs and notifications automatically.

Removing it is straightforward — but it leaves a gap:

How should the migration agent report progress to the user once KUiServerJobTracker is gone?

I’m currently exploring options for replacing it, possibly using a D-Bus-based mechanism where the agent broadcasts progress updates and a separate component (e.g., the plugin or a tray app) displays them. This would decouple the presentation layer from the agent’s logic, but I haven’t yet finalized the design.

What’s Next?

My immediate priority is to test the new plugin and the communication logic to ensure everything works correctly. In parallel, I’ll continue thinking through a robust replacement for KUiServerJobTracker, aiming for a modular, widget-free solution.

This week introduced new architectural challenges, but also laid the groundwork for cleaner, more maintainable agents. I’m excited to keep building on this momentum next week!