Failed to load schema, no error output

Describe the bug

I had a schema from AppSync which includes an AWSJSON scalar type. If I don’t define that type, graphql-codegen fails with absolutely no indication of why, just that it “Failed to load schema”

Your Example Website or App

https://codesandbox.io/s/inspiring-panna-ixxqrr?file=/schema.graphql

Steps to Reproduce the Bug or Issue

1. Open the codesandbox link.
2. Run yarn generate
3. Notice the output:

Expected behavior

Some sort of error indicating an unresolved type of AWSJSON. If I change that prop in the schema to be a String, everything works just fine.

Screenshots or Videos

No response

Platform

• OS: macOS
• NodeJS: 16.16.0
• graphql version: 16.5.0
• @graphql-codegen/* version(s): [e.g. 2.6.2] “@graphql-codegen/cli”: “^2.9.1”, “@graphql-codegen/typed-document-node”: “^2.3.2”, “@graphql-codegen/typescript-operations”: “^2.5.2”,

Codegen Config File

overwrite: true schema:

• src/generated/foo.graphql documents: null generates: src/generated/graphql.ts: plugins:
  • typescript
  • typescript-operations
  • typed-document-node config: preResolveTypes: true

Additional context

No response

[saihaj]

agreed this error message is not really helpful. We should be showing the validation error that is thrown instead of saying failed to load. The challenge is that load schema function throws and we just catch and show this error https://github.com/dotansimha/graphql-code-generator/blob/ab66ba10456a96cce0bd83ba172aae8f963bf2af/packages/graphql-codegen-cli/src/load.ts#L54-L72 rather we want to be able to differentiate Validation, Parsing and Loading which is work on @graphql-tools/ to have distinct errors for different or have more standard codes

[taschmidt]

Right, I know why it failed and how to fix it. But it’s very undesirable to not get any error message as to why the schema failed to load (i.e. unknown type “AWSJSON”). This is just an MRE showing my issue, this was initially part of a much larger, complex schema and it took a decent amount of time to troubleshoot with the only output being “Failed to load schema”.