[validator] Add suggested types to incorrect field message

Author: dschafer

src/validation/__tests__/FieldsOnCorrectType.js

@@ -15,9 +15,9 @@ import {
 } from '../rules/FieldsOnCorrectType';
 
 
-function undefinedField(field, type, line, column) {
+function undefinedField(field, type, suggestions, line, column) {
   return {
-    message: undefinedFieldMessage(field, type),
+    message: undefinedFieldMessage(field, type, suggestions),
     locations: [ { line, column } ],
   };
 }
@@ -84,8 +84,8 @@ describe('Validate: Fields on correct type', () => {
           }
         }
       }`,
-      [ undefinedField('unknown_pet_field', 'Pet', 3, 9),
-        undefinedField('unknown_cat_field', 'Cat', 5, 13) ]
+      [ undefinedField('unknown_pet_field', 'Pet', [], 3, 9),
+        undefinedField('unknown_cat_field', 'Cat', [], 5, 13) ]
     );
   });
 
@@ -94,7 +94,7 @@ describe('Validate: Fields on correct type', () => {
       fragment fieldNotDefined on Dog {
         meowVolume
       }`,
-      [ undefinedField('meowVolume', 'Dog', 3, 9) ]
+      [ undefinedField('meowVolume', 'Dog', [], 3, 9) ]
     );
   });
 
@@ -105,7 +105,7 @@ describe('Validate: Fields on correct type', () => {
           deeper_unknown_field
         }
       }`,
-      [ undefinedField('unknown_field', 'Dog', 3, 9) ]
+      [ undefinedField('unknown_field', 'Dog', [], 3, 9) ]
     );
   });
 
@@ -116,7 +116,7 @@ describe('Validate: Fields on correct type', () => {
           unknown_field
         }
       }`,
-      [ undefinedField('unknown_field', 'Pet', 4, 11) ]
+      [ undefinedField('unknown_field', 'Pet', [], 4, 11) ]
     );
   });
 
@@ -127,7 +127,7 @@ describe('Validate: Fields on correct type', () => {
           meowVolume
         }
       }`,
-      [ undefinedField('meowVolume', 'Dog', 4, 11) ]
+      [ undefinedField('meowVolume', 'Dog', [], 4, 11) ]
     );
   });
 
@@ -136,7 +136,7 @@ describe('Validate: Fields on correct type', () => {
       fragment aliasedFieldTargetNotDefined on Dog {
         volume : mooVolume
       }`,
-      [ undefinedField('mooVolume', 'Dog', 3, 9) ]
+      [ undefinedField('mooVolume', 'Dog', [], 3, 9) ]
     );
   });
 
@@ -145,7 +145,7 @@ describe('Validate: Fields on correct type', () => {
       fragment aliasedLyingFieldTargetNotDefined on Dog {
         barkVolume : kawVolume
       }`,
-      [ undefinedField('kawVolume', 'Dog', 3, 9) ]
+      [ undefinedField('kawVolume', 'Dog', [], 3, 9) ]
     );
   });
 
@@ -154,16 +154,16 @@ describe('Validate: Fields on correct type', () => {
       fragment notDefinedOnInterface on Pet {
         tailLength
       }`,
-      [ undefinedField('tailLength', 'Pet', 3, 9) ]
+      [ undefinedField('tailLength', 'Pet', [], 3, 9) ]
     );
   });
 
-  it('Defined on implmentors but not on interface', () => {
+  it('Defined on implementors but not on interface', () => {
     expectFailsRule(FieldsOnCorrectType, `
       fragment definedOnImplementorsButNotInterface on Pet {
         nickname
       }`,
-      [ undefinedField('nickname', 'Pet', 3, 9) ]
+      [ undefinedField('nickname', 'Pet', ['Cat', 'Dog'], 3, 9) ]
     );
   });
 
@@ -180,7 +180,7 @@ describe('Validate: Fields on correct type', () => {
       fragment directFieldSelectionOnUnion on CatOrDog {
         directField
       }`,
-      [ undefinedField('directField', 'CatOrDog', 3, 9) ]
+      [ undefinedField('directField', 'CatOrDog', [], 3, 9) ]
     );
   });
 
@@ -189,7 +189,15 @@ describe('Validate: Fields on correct type', () => {
       fragment definedOnImplementorsQueriedOnUnion on CatOrDog {
         name
       }`,
-      [ undefinedField('name', 'CatOrDog', 3, 9) ]
+      [
+        undefinedField(
+          'name',
+          'CatOrDog',
+          ['Being', 'Pet', 'Cat', 'Dog'],
+          3,
+          9
+        )
+      ]
     );
   });
 

src/validation/__tests__/validation.js

@@ -65,9 +65,9 @@ describe('Validate: Supports full validation', () => {
     );
 
     expect(errors).to.deep.equal([
-      { message: 'Cannot query field "catOrDog" on "QueryRoot".' },
-      { message: 'Cannot query field "furColor" on "Cat".' },
-      { message: 'Cannot query field "isHousetrained" on "Dog".' }
+      { message: 'Cannot query field "catOrDog" on type "QueryRoot".' },
+      { message: 'Cannot query field "furColor" on type "Cat".' },
+      { message: 'Cannot query field "isHousetrained" on type "Dog".' }
     ]);
   });
 

src/validation/rules/FieldsOnCorrectType.js

@@ -12,13 +12,70 @@ import type { ValidationContext } from '../index';
 import { GraphQLError } from '../../error';
 import type { Field } from '../../language/ast';
 import type { GraphQLType } from '../../type/definition';
-
+import {
+  isAbstractType,
+  GraphQLAbstractType,
+  GraphQLObjectType,
+} from '../../type/definition';
 
 export function undefinedFieldMessage(
-  fieldName: string,
-  type: GraphQLType
-): string {
-  return `Cannot query field "${fieldName}" on "${type}".`;
+    field: string,
+    type: string,
+    suggestedTypes: Array<string>): string {
+  var message = `Cannot query field "${field}" on type "${type}".`;
+  var MAX_LENGTH = 5;
+  if (suggestedTypes.length !== 0) {
+    var suggestions = suggestedTypes
+      .slice(0, MAX_LENGTH)
+      .map((t) => `"${t}"`)
+      .join(', ');
+    if (suggestedTypes.length > MAX_LENGTH) {
+      suggestions += `, and ${suggestedTypes.length - MAX_LENGTH} other types`;
+    }
+    message += ` However, this field exists on ${suggestions}.`
+    message += ` Perhaps you meant to use an inline fragment?`;
+  }
+  return message;
+}
+
+/**
+ * Return implementations of `type` that include `fieldName` as a valid field.
+ */
+function getImplementationsIncludingField(
+    type: GraphQLAbstractType,
+    fieldName: string): Array<string> {
+  return type.getPossibleTypes()
+    .filter((t) => t.getFields()[fieldName] !== undefined)
+    .map((t) => t.name)
+    .sort();
+}
+
+/**
+ * Go through all of the implementations of type, and find other interaces
+ * that they implement. If those interfaces include `field` as a valid field,
+ * return them, sorted by how often the implementations include the other
+ * interface.
+ */
+function getSiblingInterfacesIncludingField(
+    type: GraphQLAbstractType,
+    fieldName: string): Array<string> {
+  var implementingObjects = type.getPossibleTypes()
+    .filter((t) => (t instanceof GraphQLObjectType));
+
+  var suggestedInterfaces = implementingObjects.reduce((acc, t) => {
+    t.getInterfaces().forEach((i) => {
+      if (i.getFields()[fieldName] === undefined) {
+        return;
+      }
+      if (acc[i.name] === undefined) {
+        acc[i.name] = 0;
+      }
+      acc[i.name] = acc[i.name] + 1;
+    });
+    return acc;
+  }, {});
+  return Object.keys(suggestedInterfaces)
+    .sort((a,b) => suggestedInterfaces[a] - suggestedInterfaces[b]);
 }
 
 /**
@@ -34,8 +91,17 @@ export function FieldsOnCorrectType(context: ValidationContext): any {
       if (type) {
         const fieldDef = context.getFieldDef();
         if (!fieldDef) {
+          // This isn't valid. Let's find suggestions, if any.
+          var suggestedTypes = [];
+          if (isAbstractType(type)) {
+            suggestedTypes =
+              getSiblingInterfacesIncludingField(type, node.name.value);
+            suggestedTypes = suggestedTypes.concat(
+              getImplementationsIncludingField(type, node.name.value)
+            );
+          }
           context.reportError(new GraphQLError(
-            undefinedFieldMessage(node.name.value, type.name),
+            undefinedFieldMessage(node.name.value, type.name, suggestedTypes),
             [ node ]
           ));
         }