fix(gatsby): Throw Typegen errors & add IGatsbyImageData to output

[LekoArts]

Description

• Make two GraphQL errors less verbose as they are thrown when there is also a typegen error. This way the terminal overview is better
• Throw proper structured error for typegen errors
• End activity and don't panic during develop
• Always use validation for documents to get proper error messages
• Update flag description and not mark as experimental anymore
• Use IGatsbyImageData type for gatsbyImageData

Documentation

I'll add a docsUrl to the error in #35584

Related Issues

[ch50768]
[ch50542]
#35420 (comment)

[aaronadamsCA]

Oh good, I was just coincidentally checking how you worked around the generic JSON scalar type.

Related feature request: #33317

[aaronadamsCA]

Also, if this helps, in our environment the gatsby-plugin-image#IGatsbyImageData syntax didn't work. We had to use a dynamic import expression (import('gatsby-plugin-image').IGatsbyImageData) instead.

[LekoArts]

Also, if this helps, in our environment the gatsby-plugin-image#IGatsbyImageData syntax didn't work. We had to use a dynamic import expression (import('gatsby-plugin-image').IGatsbyImageData) instead.

Works in my testing. It adds

import type { IGatsbyImageData } from 'gatsby-plugin-image';

At the top of the file and then reuses that in the scalars

type Scalars = {
  GatsbyImageData: IGatsbyImageData;
  JSON: Record<string, unknown>;
};

[LekoArts]

Oh, you were right. The global namespace doesn't work if you add an import, so I switched it to the dynamic import.

Luckily this was also caught by the e2e tests 👍

[LekoArts]

@aaronadamsCA which other generic JSON scalars did you run into? I can change others, too

[aaronadamsCA]

@LekoArts That was the only one we had encountered so far.

Looking forward to seeing this ship!

[wardpeet]

Looks good, do you want to do the same for imageCDN located in gatsby-plugin-utils?