Adding a Union type to schema breaks all @lambdas

we have several @lambda fields that we have used without incident until today when we added a union to our schema. This broke all our lambdas.

Sure enough, commenting out that union and hitting ‘deploy’ fixes the lambdas immediately.

Report a GraphQL Bug

What edition and version of Dgraph are you using?


  • SlashGraphQL
  • Dgraph (community edition/Dgraph Cloud)

Dgraph Version: v20.11.2-rc1-16-g4d041a3a

Have you tried reproducing the issue with the latest release?


Steps to reproduce the issue (paste the query/schema if possible)

[can provide full schema and lambda scripts if needed]

  1. Push GraphQL Schema without union
  2. Push lambda with field resolver
  3. Add union to GraphQL Schema
  4. Remove union from GraphQL Schema

Expected behaviour and actual result.

After step 2 everything is working
After step 3 field lambda no longer works. No errors in lambda log, no errors in schema update, no errors in GraphQL query.
After step 4 field lambda is working again. Only change made was comment out union from schema

oh thats how you report a bug!

@gja do you think this is cloud related or should this be an issue on GraphQL category?

This category is fine

This is unlikely to be a bug in the cloud, so tagging @abhimanyusinghgaur

Can you also share the schema (before and after union) ?

Let me try to reproduce with a smaller schema

Thanks @amaster507.

Please share the schemas and the query to reproduce, and we will look into it.
Feel free to DM me if the schema is private.