Ensure Non-isolation of Nodes

[lupeterm]

Hi all,

I just came a cross a situation where an object ends up isolated in the end.
Consider the following simple example:

type document
  relations
    define owner: [user] 
    define can_edit: [user] or owner

In my actual use case, but applied to this model, user:tom would create document:a and set another user:lisa as owner. Additionally, tom would temporarily maintain the can_edit role until lisa assumes ownership.

The way our system is currently designed, there is an edge case where both tom and lisa could theoretically lose the can_edit role, leading to document:a being an isolated node to which noone has write access.

Obviously, this can easily be handled by a preceding call to check if removing an edge would isolate the node, but I was wondering If this could be a useful feature to be added in the future.

I dont think this would be implemented on the model definition level, but rather as an extra optional flag on the write call, e.g.:

fga tuple write --store-id=${FGA_STORE_ID} --model-id=${FGA_MODEL_ID} --allow_isolation user:tom can_edit document:a

, with true being the default.

[dyeam0]

Hi @lupeterm, that's an interesting idea for the optional flag to allow/prevent this condition. Currently, it is the application's responsibility for isolation prevention. Using such a flag would have some performance implications, adding latency in large graphs, but as an optional flag, then it can be left up to the developer to decide whether it is worth using or not.

We would not be able to prioritize something like this in the near-term but I'll add this to our roadmap inbound for future consideration.

[dyeam0]

@lupeterm An FYI, we won't open a whole roadmap item for this but we will add this discussion as community feedback for our modeling improvement initiatives.