Merge pull request #296 from jjergus/master

Validate: Unique variable names

Author: leebyron

src/validation/__tests__/UniqueVariableNames.js

@@ -0,0 +1,47 @@
+/**
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+import { describe, it } from 'mocha';
+import { expectPassesRule, expectFailsRule } from './harness';
+import {
+  UniqueVariableNames,
+  duplicateVariableMessage,
+} from '../rules/UniqueVariableNames';
+
+
+function duplicateVariable(name, l1, c1, l2, c2) {
+  return {
+    message: duplicateVariableMessage(name),
+    locations: [ { line: l1, column: c1 }, { line: l2, column: c2 } ],
+  };
+}
+
+describe('Validate: Unique variable names', () => {
+
+  it('unique variable names', () => {
+    expectPassesRule(UniqueVariableNames, `
+      query A($x: Int, $y: String) { __typename }
+      query B($x: String, $y: Int) { __typename }
+    `);
+  });
+
+  it('duplicate variable names', () => {
+    expectFailsRule(UniqueVariableNames, `
+      query A($x: Int, $x: Int, $x: String) { __typename }
+      query B($x: String, $x: Int) { __typename }
+      query C($x: Int, $x: Int) { __typename }
+    `, [
+      duplicateVariable('x', 2, 16, 2, 25),
+      duplicateVariable('x', 2, 16, 2, 34),
+      duplicateVariable('x', 3, 16, 3, 28),
+      duplicateVariable('x', 4, 16, 4, 25)
+    ]);
+  });
+
+});

src/validation/rules/UniqueVariableNames.js

@@ -0,0 +1,43 @@
+/* @flow */
+/**
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+import type { ValidationContext } from '../index';
+import type { VariableDefinition } from '../../language/ast';
+import { GraphQLError } from '../../error';
+
+
+export function duplicateVariableMessage(variableName: string): string {
+  return `There can be only one variable named "${variableName}".`;
+}
+
+/**
+ * Unique variable names
+ *
+ * A GraphQL operation is only valid if all its variables are uniquely named.
+ */
+export function UniqueVariableNames(context: ValidationContext): any {
+  let knownVariableNames = Object.create(null);
+  return {
+    OperationDefinition() {
+      knownVariableNames = Object.create(null);
+    },
+    VariableDefinition(node: VariableDefinition) {
+      const variableName = node.variable.name.value;
+      if (knownVariableNames[variableName]) {
+        context.reportError(new GraphQLError(
+          duplicateVariableMessage(variableName),
+          [ knownVariableNames[variableName], node.variable.name ]
+        ));
+      } else {
+        knownVariableNames[variableName] = node.variable.name;
+      }
+    }
+  };
+}

src/validation/specifiedRules.js

@@ -44,6 +44,9 @@ import { PossibleFragmentSpreads } from './rules/PossibleFragmentSpreads';
 // Spec Section: "Fragments must not form cycles"
 import { NoFragmentCycles } from './rules/NoFragmentCycles';
 
+// Spec Section: "Variable Uniqueness"
+import { UniqueVariableNames } from './rules/UniqueVariableNames';
+
 // Spec Section: "All Variable Used Defined"
 import { NoUndefinedVariables } from './rules/NoUndefinedVariables';
 
@@ -97,6 +100,7 @@ export const specifiedRules: Array<(context: ValidationContext) => any> = [
   NoUnusedFragments,
   PossibleFragmentSpreads,
   NoFragmentCycles,
+  UniqueVariableNames,
   NoUndefinedVariables,
   NoUnusedVariables,
   KnownDirectives,