fix(schema): Remove accidental capitalization of lowercase typenames.

packages/gatsby/src/schema/__tests__/build-schema.js

@@ -337,6 +337,32 @@ describe(`Build schema`, () => {
         })
       )
     })
+
+    it(`allows modifying nested types`, async () => {
+      createTypes(`
+        type PostFrontmatter {
+          published: Boolean!
+          newField: String
+        }
+
+        type Post implements Node {
+          frontmatter: PostFrontmatter
+        }
+      `)
+
+      const schema = await buildSchema()
+
+      const type = schema.getType(`Post`)
+      const fields = type.getFields()
+      expect(fields[`frontmatter`].type.toString()).toEqual(`PostFrontmatter`)
+      const nestedType = schema.getType(`PostFrontmatter`)
+      const nestedFields = nestedType.getFields()
+      expect(nestedFields[`authors`].type.toString()).toEqual(`[String]`)
+      expect(nestedFields[`reviewers`].type.toString()).toEqual(`[String]`)
+      expect(nestedFields[`published`].type.toString()).toEqual(`Boolean!`)
+      expect(nestedFields[`date`].type.toString()).toEqual(`Date`)
+      expect(nestedFields[`newField`].type.toString()).toEqual(`String`)
+    })
   })
 
   describe(`createResolvers`, () => {

packages/gatsby/src/schema/infer/__tests__/__snapshots__/infer.js.snap

@@ -253,6 +253,27 @@ Object {
 }
 `;
 
+exports[`GraphQL type inference handles lowercase type names 1`] = `
+Object {
+  "data": Object {
+    "allWordpressPage": Object {
+      "edges": Array [
+        Object {
+          "node": Object {
+            "__typename": "wordpress__PAGE",
+            "acfFields": Object {
+              "__typename": "wordpress__PAGEAcfFields",
+              "fooz": "bar",
+            },
+            "id": "1",
+          },
+        },
+      ],
+    },
+  },
+}
+`;
+
 exports[`GraphQL type inference type conflicts catches conflicts and removes field 1`] = `
 Array [
   TypeConflictEntry {

packages/gatsby/src/schema/infer/__tests__/infer.js

@@ -408,6 +408,50 @@ describe(`GraphQL type inference`, () => {
     expect(result).toMatchSnapshot()
   })
 
+  it(`handles lowercase type names`, async () => {
+    const nodes = [
+      {
+        id: `1`,
+        internal: { type: `wordpress__PAGE` },
+        acfFields: {
+          fooz: `bar`,
+        },
+      },
+    ]
+    const schema = await buildTestSchema(nodes)
+    store.dispatch({ type: `SET_SCHEMA`, payload: schema })
+    const result = await graphql(
+      schema,
+      `
+        query {
+          allWordpressPage {
+            edges {
+              node {
+                __typename
+                id
+                acfFields {
+                  fooz
+                  __typename
+                }
+              }
+            }
+          }
+        }
+      `,
+      undefined,
+      {
+        path: `/`,
+        nodeModel: new LocalNodeModel({
+          schema,
+          nodeStore,
+          createPageDependency,
+        }),
+      }
+    )
+
+    expect(result).toMatchSnapshot()
+  })
+
   describe(`Handles dates`, () => {
     it(`Handles integer with valid date format`, async () => {
       const nodes = [

packages/gatsby/src/schema/infer/add-inferred-fields.js

@@ -78,7 +78,7 @@ const addInferredFieldsImpl = ({
         .map(field => `\`${field.unsanitizedKey}\``)
         .join(`, `)
       report.warn(
-        `Multiple node fields resolve to the same GraphQL field \`${
+        `Multiple node fields resolve to the same GraphQL field \`${prefix}.${
           field.key
         }\` - [${possibleFieldsNames}]. Gatsby will use \`${
           field.unsanitizedKey
@@ -385,12 +385,12 @@ const getSimpleFieldConfig = ({
 }
 
 const createTypeName = selector => {
-  const key = selector
-    .split(`.`)
+  const keys = selector.split(`.`)
+  const suffix = keys
+    .slice(1)
     .map(_.upperFirst)
     .join(``)
-
-  return key
+  return `${keys[0]}${suffix}`
 }
 
 const NON_ALPHA_NUMERIC_EXPR = new RegExp(`[^a-zA-Z0-9_]`, `g`)

packages/gatsby/src/schema/infer/index.js

@@ -68,7 +68,7 @@ const addInferredTypes = ({
   })
 
   // XXX(freiksenet): We iterate twice to pre-create all types
-  const typeComposers = typeNames.map(typeName => {
+  const typeComposers = typeNames.map(typeName =>
     addInferredType({
       schemaComposer,
       nodeStore,
@@ -77,7 +77,7 @@ const addInferredTypes = ({
       typeMapping,
       parentSpan,
     })
-  })
+  )
 
   if (noNodeInterfaceTypes.length > 0) {
     noNodeInterfaceTypes.forEach(type => {