Advanced Breaking Change Detection

[n1ru4l]

Background

Currently, we visit fields, variables, arguments, and object fields in DocumentNode, collect their return types and parent types, and turn them into schema coordinates. When a schema is modified, Hive creates a list of touched schema coordinates and checks in ClickHouse if a schema coordinate was registered or not and if it’s a breaking change or not.

This is too safe 🙂 

There are scenarios where a change detected as a breaking change might not really be a breaking change. See https://github.com/kamilkisiela/graphql-breaking-changes

Some examples:

• Changing type String to ID does not break clients (unless the scalar is used in a operation arguments definition
• Changing Int to Int! for an argument is not breaking if all operation argument usages already define it as Int!
• Renaming an Object type is not breaking if the __typename is not used.

We want to be able to cover these kind of "safe" breaking changes with our breaking change detection.

Resources

• RFC Document

[jdolle]

I'll take a look at this.

[n1ru4l]

This is now implemented and shipped.