Mergefull

A way to synchronise items with safe merge conflicts.

Related project

If the collection that you are syncing has immutable items, you will be better off using mergeless instead.

Implementation overview

Situation: Multiple clients (for example a note synchronisation app) want to sync with a server storing state for them. Goal: Get clients to agree on the collection of items and prevent that one client accidentally overrides a value saved by another client. Solution: Store a server-side name and monotonically increasing number (revision number of the data, or current time) for each number.

See the following blogposts for (many) more details:

• https://cs-syd.eu/posts/2019-10-14-mergeful-value
• https://cs-syd.eu/posts/2019-11-28-mergeful-item
• https://cs-syd.eu/posts/2019-12-28-mergeful-collection

or the talk at Haskellerz:

https://www.youtube.com/watch?v=MkbhHmAk47k