How to make ConnectionTypes error resilient

[Bertg]

We serve search results using GraphQL. This results is basically looks something like this:

field :searchResult, Type::SearchResult.connection_type, null: false

The SearchResult returns a Node and some search result meta data. However, at this time the search system sometimes returns values "that don't make sense" and cause an error in the result. Most commonly it's a Cannot return null for non-nullable field for either the node, or some nested field.

What I would like to do, while we fix the root issue, is to still return any valid result. So instead of completely erroring out, we should just be ignoring the edge/node that that is causing the error.

To be clear, say that the search database returns 5 results, of which 2 cause an issue in the graph response, then I would like to still have a response containing 3 edges/nodes.

How could this be done?

[Bertg]

I've dug some more into this issue, and have discovered some things.

In our codebase we have added node_nullable(false) to our connections. this basically means that the "null" error keeps cascading up until the data level, as per the documentation.

So what I'm actually looking for is to replace the non-null-error-propagation behaviour with a non-null-error-compact option. Here compact would be similar to how the ruby compact method works.

@rmosolgo would this be something you are open to considering?

[amomchilov]

We have a need for this too, and I've implemented a working proof-of-concept. Here's an issue I opened about this: #4496

It's certainly possible, but will need some work to upstream, if Robert is even interested in such a feature.