Schema Customization - Cannot Query Field "childImageSharpe" on type "File"

[ryanwiemer]

Description

While developing a Gatsby Theme I customized the GraphQL schema (gatsby-node.js). This works as expected with all fields except the cover front matter field used for a cover image. If I omit the cover image on all posts the site still builds but if there are no posts at all I receive the following error message:

GraphQLError: Cannot query field "childImageSharp" on type "File"

Steps to reproduce

1. git clone https://github.com/ryanwiemer/gatsby-theme-amsterdam
2. yarn install
3. Remove the content folder in site/content/
4. yarn workspace site develop - To start development using the site folder
5. You should now see the error message: GraphQLError: Cannot query field "childImageSharp" on type "File"

Expected result

Since I defined the schema through the Schema Customization I expect the site to build even when there is no content.

Actual result

The site fails to build.

Environment

System:
OS: macOS High Sierra 10.13.6
CPU: (8) x64 Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 12.6.0 - /var/folders/v8/dxrbb0vj7z9dtxj7mq5tc101d1qq1d/T/yarn--1564090827764-0.3745122210652396/node
Yarn: 1.17.3 - /var/folders/v8/dxrbb0vj7z9dtxj7mq5tc101d1qq1d/T/yarn--1564090827764-0.3745122210652396/yarn
npm: 6.10.2 - /usr/local/bin/npm
Languages:
Python: 2.7.10 - /usr/bin/python
Browsers:
Chrome: 75.0.3770.142
Firefox: 67.0.4
Safari: 12.1.2

[stefanprobst]

Thanks for reporting this! The issue is that currently child* fields are not automatically created when we have no nodes for that type in the data layer. But we now have a childOf extension to explicitly define those parent/child relations. See #16109

A quick unrelated comment on the type defs in your theme's gatsby-node.js:
the Fields type should not implement the Node interface. Only top-level types, i.e. those created by source/transformer plugins should do that. (you'll see that currently you have fields and allFields root query types)

[ryanwiemer]

@stefanprobst Thank you for the quick response!

Also thank you for the tip on my type definitions. I will fix that.