Another which module question ... I know. Sorry for that. But time changes answers.
I need transitive bi-directional references, where both ends know from each other (to handle them with rules, actions and tokens) and also their wanted imaginated "position" in their relation (higher, lower, left,right), you name it. While I was very impressed by the kick start of relation module, which seems to be able to do that, and which had immense support from long term Drupal supporters like CHX, I am scared now of if this project would scale in the next years continuously. I can't force it. The API looks good and naught101 and others are around and very smart, but the project feels a little bit isolated in Drupal land and I can imagine that it isn't the maintainers most wanted life plan to fight for relation module. I know the question is old but in the moment the wind changes and the question is new. I am a contributor (patches, modules), but I am not in the position to change the wind in the woods, if you know would I mean. And I have to care about the route for this, because it is strongly connected to my self-employed project. I always share but this time I have to care about the outcome of the right decision.
So, my question is: do I need to put my power in the relation module and help their (no problem with that) to get deeper into it to come closer to my approach or would it be more smart to try to get it done with the so entitled more "limited" entity references module, which seems to be well supported ATM and is part of the D8 campaign? I would like to hear your opinions.
Naught was so kind to mention on the project page of relation, that this kind of relations are maybe also possible to made with entity references, but only under certain circumstances and a third connector entity. But does the referred entity "know" that it was chosen from another? I don't think so.
Let's paint an example near to mine: A task can only be set to fixed, when a "lower" related task in the hierarchy is set to "fixed". Before that, rules would hide the fixed button for this task. That means many tasks are related to each other and really "know" each other and are in a flexible hierarchy and it can change its weight, if one task gets the milestone of the other task. On both ends you can see the relation to the other. I am not sure if entity references is able to do this. Even if I have views and 3,4,6 own patches at hand showing the references on each ends, there is still this slidely "feeling" of only one "real" direction which refers to only one end. Isn't it? Sorry for the old question but we need a refresh on this...
- How can I implement 3-way relationship (reference) between entities?
- Relation vs. References vs. Entity Reference for managing node-reference-type relationships
Another question is: do I come into trouble having them both on the same project?