refactor: update e2e test schema

WIP - first try to use union for reference field with validations

fix multi reference fields

shorten union names

support multiple reference fields for a single content type

fix: type name generation

remove comment

introduce validation for single reference fields

e2e-tests/contentful/schema.gql

@@ -124,7 +124,7 @@ type SiteBuildMetadata implements Node @dontInfer {
 
 interface ContentfulReference implements Node {
   id: ID!
-  sys: ContentfulSys
+  sys: ContentfulSys!
 }
 
 type ContentfulSys {
@@ -145,13 +145,23 @@ 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 ContentfulAsset implements ContentfulReference & Node @dontInfer {
-  sys: ContentfulSys
+  sys: ContentfulSys!
   title: String
   description: String
   contentType: String
@@ -203,7 +213,8 @@ 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 +223,8 @@ 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 +236,8 @@ 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 +246,16 @@ 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
@@ -249,29 +264,33 @@ 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
+  sys: ContentfulSys!
+  metadata: ContentfulMetadata!
   title: String
   one: ContentfulEntry @link(by: "id", from: "one___NODE")
   oneLocalized: ContentfulEntry @link(by: "id", from: "oneLocalized___NODE")
@@ -280,7 +299,8 @@ type ContentfulContentTypeContentReference implements ContentfulReference & Cont
 }
 
 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")

e2e-tests/contentful/src/pages/content-reference.js

@@ -109,8 +109,10 @@ export const pageQuery = graphql`
         }
         one {
           __typename
-          sys {
-            id
+          ... on ContentfulEntry {
+            sys {
+              id
+            }
           }
           ... on ContentfulContentTypeText {
             title
@@ -152,8 +154,10 @@ export const pageQuery = graphql`
         }
         many {
           __typename
-          sys {
-            id
+          ... on ContentfulEntry {
+            sys {
+              id
+            }
           }
           ... on ContentfulContentTypeText {
             title
@@ -165,6 +169,11 @@ export const pageQuery = graphql`
           }
           ... on ContentfulContentTypeContentReference {
             title
+            ... on ContentfulEntry {
+              sys {
+                id
+              }
+            }
             one {
               ... on ContentfulContentTypeText {
                 title

e2e-tests/contentful/src/pages/rich-text.js

@@ -156,8 +156,10 @@ export const pageQuery = graphql`
                   title
                   one {
                     __typename
-                    sys {
-                      id
+                    ... on ContentfulEntry {
+                      sys {
+                        id
+                      }
                     }
                     ... on ContentfulContentTypeText {
                       title
@@ -179,8 +181,10 @@ export const pageQuery = graphql`
                   }
                   many {
                     __typename
-                    sys {
-                      id
+                    ... on ContentfulEntry {
+                      sys {
+                        id
+                      }
                     }
                     ... on ContentfulContentTypeText {
                       title

packages/gatsby-source-contentful/src/generate-schema.js

@@ -70,7 +70,64 @@ const ContentfulDataTypes = new Map([
   ],
 ])
 
-const getLinkFieldType = (linkType, field) => {
+const unionsNameSet = new Set()
+
+const getLinkFieldType = (linkType, field, schema, createTypes) => {
+  // Check for validations
+  const validations =
+    field.type === `Array` ? field.items?.validations : field?.validations
+
+  if (validations) {
+    // We only handle content type validations
+    const linkContentTypeValidation = validations.find(
+      ({ linkContentType }) => !!linkContentType
+    )
+    if (linkContentTypeValidation) {
+      const { linkContentType } = linkContentTypeValidation
+      const contentTypes = Array.isArray(linkContentType)
+        ? linkContentType
+        : [linkContentType]
+
+      // Full type names for union members, shorter variant for the union type name
+      const translatedTypeNames = contentTypes.map(typeName =>
+        makeTypeName(typeName)
+      )
+      const shortTypeNames = contentTypes.map(typeName =>
+        makeTypeName(typeName, ``)
+      )
+
+      // Single content type
+      if (translatedTypeNames.length === 1) {
+        return {
+          type: translatedTypeNames.shift(),
+          extensions: {
+            link: { by: `id`, from: `${field.id}___NODE` },
+          },
+        }
+      }
+
+      // Multiple content types
+      const unionName = [`UnionContentful`, ...shortTypeNames].join(``)
+
+      if (!unionsNameSet.has(unionName)) {
+        unionsNameSet.add(unionName)
+        createTypes(
+          schema.buildUnionType({
+            name: unionName,
+            types: translatedTypeNames,
+          })
+        )
+      }
+
+      return {
+        type: unionName,
+        extensions: {
+          link: { by: `id`, from: `${field.id}___NODE` },
+        },
+      }
+    }
+  }
+
   return {
     type: `Contentful${linkType}`,
     extensions: {
@@ -79,19 +136,19 @@ const getLinkFieldType = (linkType, field) => {
   }
 }
 
-const translateFieldType = field => {
+const translateFieldType = (field, schema, createTypes) => {
   let fieldType
   if (field.type === `Array`) {
     // Arrays of Contentful Links or primitive types
     const fieldData =
       field.items.type === `Link`
-        ? getLinkFieldType(field.items.linkType, field)
-        : translateFieldType(field.items)
+        ? getLinkFieldType(field.items.linkType, field, schema, createTypes)
+        : translateFieldType(field.items, schema, createTypes)
 
     fieldType = { ...fieldData, type: `[${fieldData.type}]` }
   } else if (field.type === `Link`) {
     // Contentful Link (reference) field types
-    fieldType = getLinkFieldType(field.linkType, field)
+    fieldType = getLinkFieldType(field.linkType, field, schema, createTypes)
   } else {
     // Primitive field types
     fieldType = ContentfulDataTypes.get(field.type)(field)
@@ -371,7 +428,7 @@ export function generateSchema({
         if (field.disabled || field.omitted) {
           return
         }
-        fields[field.id] = translateFieldType(field)
+        fields[field.id] = translateFieldType(field, schema, createTypes)
       })
 
       const type = pluginConfig.get(`useNameForId`)

packages/gatsby-source-contentful/src/normalize.js

@@ -1,8 +1,7 @@
 // @ts-check
 import _ from "lodash"
 
-const typePrefix = `ContentfulContentType`
-export const makeTypeName = type =>
+export const makeTypeName = (type, typePrefix = `ContentfulContentType`) =>
   _.upperFirst(_.camelCase(`${typePrefix} ${type}`))
 
 export const getLocalizedField = ({ field, locale, localesFallback }) => {