Proposal - Automatic and Manual Conflict Resolver

Overview:
This project focuses on handling node conflicts. Currently when a user tries to save a node that has been edited (and saved) before they have submitted, an error appears and the edit is blocked. This module aims to resolve these issues automatically if possible. If not, it will provide tools and an interface to interactively merge the two different versions of the node.

Idea Link:
http://groups.drupal.org/node/20472

Description:
As Chx so aptly put it not allowing a user to save the new node is “not nice.” From a user’s perspective this could be infuriating. Imagine spending 30 minutes extensively updating and correcting a node just to have another user come in and lock you out from saving your changes. Locking the node from being edited while another user is editing also has its disadvantages, should one user begin editing a node and not save for a while, the node would remain locked, thus limiting content contribution possibilities. The solution for these woes?

A conflict resolver, but not just a simple warning that the source content has change with rudimentary merging tools. The goal of this project is to automate as much as possible, by attempting to generate a patch based on the changes and applying it. If the patch can be applied to the current version, apply and merrily continue on our way. If not, go into manual mode and present a diff of the two revisions and an interface / tools to merge the two. As mentioned in the post for the original idea the module should compare all aspects of the node, not just the body. This would, at a minimum, include CCK fields.

Timeline / Basic Roadmap:
April 20th:

• Determine acceptance and begin work on the project

April 20th - May 23rd:

• Determine module workflow (generate diagrams concerning program flow and user interface).
• Research various diff processes (native to host, PHP, other tools).
• Setup project on d.o and community feedback area on g.d.o.
• Discuss with mentors and community optimal project direction and tune roadmap to the tasks required
  • Determine time and format mentors would like updates and code reviews / commits

May 23rd - July 6th:

• Code basic settings area (this will be extended throughout development)
• Code diff logic (whether this involves some super advanced PHP diff solution or running diff on the server all that happens here)
• Code patch generation and test applying the patch to the “working node”
• Code auto resolution using both diff and patch code previously mentioned
• At this point should the automatic resolution fail we will still supply error that the node content cannot be changed.

July 6th - August 10th:

• Code Manual conflict resolution
  • Involves displaying the diff to the user in a friendly way
  • Let the user interact with the two versions and store the result
• Develop D7 Port

Mentors:
Chx
Davidstrauss

Difficulty:
Medium - The interface for comparing and merging all data between the two nodes will be the largest task. Keeping it clean and usable will be top priority.

About Me:
My name is Christopher Bradford and I am a student studying Computer Science. I have been working with Drupal for the past 3 years beginning with the BitTorrent module for SoC 2007. I am experienced in developing modules and themes for the Drupal community and clients in both Drupal 5 and Drupal 6 environments. Last year I was part of SoC with the DocAPI project. I would like to note that while last year’s project did not succeed, I am very confident in my abilities and the outcome of this years proposal. Given a problem, I will tirelessly work to find a solution, leaning not only on my own understanding, but researching in various places and asking others for help. I look forward to this year’s Summer of Code and the projects it produces for the community.