feat: use union for reference fields with validation (#31395)

Also:

* test: add unit tests for schema customization

* fix: rich text inline rendering

* test: update e2e test schema dump

e2e-tests/contentful/schema.gql

@@ -74,8 +74,6 @@ type Directory implements Node @dontInfer {
 type Site implements Node @dontInfer {
   buildTime: Date @dateformat
   siteMetadata: SiteSiteMetadata
-  port: Int
-  host: String
   polyfill: Boolean
   pathPrefix: String
   jsxRuntime: String
@@ -124,12 +122,11 @@ type SiteBuildMetadata implements Node @dontInfer {
 
 interface ContentfulReference implements Node {
   id: ID!
-  sys: ContentfulSys
+  sys: ContentfulSys!
 }
 
-type ContentfulSys {
+type ContentfulSys implements Node @dontInfer {
   type: String!
-  id: String!
   spaceId: String!
   environmentId: String!
   contentType: ContentfulContentType @link(by: "id", from: "contentType___NODE")
@@ -145,13 +142,27 @@ type ContentfulContentType implements Node @dontInfer {
   description: String!
 }
 
-interface ContentfulEntry implements Node {
+interface ContentfulEntry implements ContentfulReference & Node {
   id: ID!
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
+}
+
+type ContentfulMetadata @dontInfer {
+  tags: [ContentfulTag]! @link(by: "id", from: "tags___NODE")
+}
+
+type ContentfulTag implements Node @dontInfer {
+  name: String!
+  contentful_id: String!
+}
+
+type ContentfulAssetFields @dontInfer {
+  localFile: File @link(by: "id")
 }
 
 type ContentfulAsset implements ContentfulReference & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
   title: String
   description: String
   contentType: String
@@ -163,15 +174,6 @@ type ContentfulAsset implements ContentfulReference & Node @dontInfer {
   fields: ContentfulAssetFields
 }
 
-type ContentfulAssetFields {
-  localFile: String
-}
-
-type ContentfulTag implements Node @dontInfer {
-  name: String!
-  contentful_id: String!
-}
-
 type ContentfulRichTextAssets {
   block: [ContentfulAsset]!
   hyperlink: [ContentfulAsset]!
@@ -203,7 +205,8 @@ type ContentfulText implements Node @dontInfer {
 }
 
 type ContentfulContentTypeNumber implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   integer: Int
   integerLocalized: Int
@@ -212,7 +215,8 @@ type ContentfulContentTypeNumber implements ContentfulReference & ContentfulEntr
 }
 
 type ContentfulContentTypeText implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   short: String
   shortLocalized: String
@@ -224,7 +228,8 @@ type ContentfulContentTypeText implements ContentfulReference & ContentfulEntry
 }
 
 type ContentfulContentTypeMediaReference implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   one: ContentfulAsset @link(by: "id", from: "one___NODE")
   oneLocalized: ContentfulAsset @link(by: "id", from: "oneLocalized___NODE")
@@ -233,14 +238,16 @@ type ContentfulContentTypeMediaReference implements ContentfulReference & Conten
 }
 
 type ContentfulContentTypeBoolean implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   boolean: Boolean
   booleanLocalized: Boolean
 }
 
 type ContentfulContentTypeDate implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   date: Date @dateformat
   dateTime: Date @dateformat
@@ -249,44 +256,53 @@ type ContentfulContentTypeDate implements ContentfulReference & ContentfulEntry
 }
 
 type ContentfulContentTypeLocation implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   location: ContentfulLocation
   locationLocalized: ContentfulLocation
 }
 
 type ContentfulContentTypeJson implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   json: JSON
   jsonLocalized: JSON
 }
 
 type ContentfulContentTypeRichText implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   richText: ContentfulRichText
   richTextLocalized: ContentfulRichText
   richTextValidated: ContentfulRichText
 }
 
-type ContentfulContentTypeContentReference implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+type ContentfulContentTypeContentReference implements ContentfulReference & ContentfulEntry & Node @isPlaceholder @dontInfer {
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   one: ContentfulEntry @link(by: "id", from: "one___NODE")
   oneLocalized: ContentfulEntry @link(by: "id", from: "oneLocalized___NODE")
-  many: [ContentfulEntry] @link(by: "id", from: "many___NODE")
+  many: [UnionContentfulContentReferenceNumberText] @link(by: "id", from: "many___NODE")
   manyLocalized: [ContentfulEntry] @link(by: "id", from: "manyLocalized___NODE")
 }
 
+union UnionContentfulContentReferenceNumberText = ContentfulContentTypeContentReference | ContentfulContentTypeNumber | ContentfulContentTypeText
+
+union UnionContentfulNumberText = ContentfulContentTypeNumber | ContentfulContentTypeText
+
 type ContentfulContentTypeValidatedContentReference implements ContentfulReference & ContentfulEntry & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
-  oneItemSingleType: ContentfulEntry @link(by: "id", from: "oneItemSingleType___NODE")
-  oneItemManyTypes: ContentfulEntry @link(by: "id", from: "oneItemManyTypes___NODE")
+  oneItemSingleType: ContentfulContentTypeText @link(by: "id", from: "oneItemSingleType___NODE")
+  oneItemManyTypes: UnionContentfulNumberText @link(by: "id", from: "oneItemManyTypes___NODE")
   oneItemAllTypes: ContentfulEntry @link(by: "id", from: "oneItemAllTypes___NODE")
-  multipleItemsSingleType: [ContentfulEntry] @link(by: "id", from: "multipleItemsSingleType___NODE")
-  multipleItemsManyTypes: [ContentfulEntry] @link(by: "id", from: "multipleItemsManyTypes___NODE")
+  multipleItemsSingleType: [ContentfulContentTypeText] @link(by: "id", from: "multipleItemsSingleType___NODE")
+  multipleItemsManyTypes: [UnionContentfulNumberText] @link(by: "id", from: "multipleItemsManyTypes___NODE")
   multipleItemsAllTypes: [ContentfulEntry] @link(by: "id", from: "multipleItemsAllTypes___NODE")
 }
 
@@ -317,7 +333,7 @@ type MarkdownWordCount {
   words: Int
 }
 
-type MarkdownRemark implements Node @childOf(mimeTypes: ["text/markdown", "text/x-markdown"], types: ["ContentfulText"]) @dontInfer {
+type MarkdownRemark implements Node @childOf(mimeTypes: ["text/markdown", "text/x-markdown"], types: ["ContentfulText"]) @derivedTypes @dontInfer {
   frontmatter: MarkdownRemarkFrontmatter
   excerpt: String
   rawMarkdownBody: String
@@ -481,7 +497,7 @@ type ImageSharpResize {
   originalName: String
 }
 
-type ImageSharp implements Node @childOf(mimeTypes: [], types: ["File"]) @dontInfer {
+type ImageSharp implements Node @childOf(types: ["File"]) @dontInfer {
   fixed(width: Int, height: Int, base64Width: Int, jpegProgressive: Boolean = true, pngCompressionSpeed: Int = 4, grayscale: Boolean = false, duotone: DuotoneGradient, traceSVG: Potrace, quality: Int, jpegQuality: Int, pngQuality: Int, webpQuality: Int, toFormat: ImageFormat = AUTO, toFormatBase64: ImageFormat = AUTO, cropFocus: ImageCropFocus = ATTENTION, fit: ImageFit = COVER, background: String = "rgba(0,0,0,1)", rotate: Int = 0, trim: Float = 0): ImageSharpFixed
   fluid(
     maxWidth: Int
@@ -652,7 +668,7 @@ enum GatsbyImagePlaceholder {
   NONE
 }
 
-type ContentfulContentTypeContentType implements Node @dontInfer {
+type ContentfulContentTypeContentType implements Node @derivedTypes @dontInfer {
   name: String
   displayField: String
   description: String