Validate: Unique variable names

Commit:
089caad3628e69003d79675558fe38023af02d31 [089caad]
Parents:
9234c6da0e
Author:
Jan Jergus <[email protected]>
Date:
18 February 2016 at 7:00:39 AM SGT
Commit Date:
18 February 2016 at 8:47:14 AM SGT

rules.go

@@ -36,6 +36,7 @@ var SpecifiedRules = []ValidationRuleFn{
 	UniqueFragmentNamesRule,
 	UniqueInputFieldNamesRule,
 	UniqueOperationNamesRule,
+	UniqueVariableNamesRule,
 	VariablesAreInputTypesRule,
 	VariablesInAllowedPositionRule,
 }
@@ -1735,6 +1736,54 @@ func UniqueOperationNamesRule(context *ValidationContext) *ValidationRuleInstanc
 	}
 }
 
+/**
+ * Unique variable names
+ *
+ * A GraphQL operation is only valid if all its variables are uniquely named.
+ */
+func UniqueVariableNamesRule(context *ValidationContext) *ValidationRuleInstance {
+	knownVariableNames := map[string]*ast.Name{}
+
+	visitorOpts := &visitor.VisitorOptions{
+		KindFuncMap: map[string]visitor.NamedVisitFuncs{
+			kinds.OperationDefinition: visitor.NamedVisitFuncs{
+				Kind: func(p visitor.VisitFuncParams) (string, interface{}) {
+					if node, ok := p.Node.(*ast.OperationDefinition); ok && node != nil {
+						knownVariableNames = map[string]*ast.Name{}
+					}
+					return visitor.ActionNoChange, nil
+				},
+			},
+			kinds.VariableDefinition: visitor.NamedVisitFuncs{
+				Kind: func(p visitor.VisitFuncParams) (string, interface{}) {
+					if node, ok := p.Node.(*ast.VariableDefinition); ok && node != nil {
+						variableName := ""
+						var variableNameAST *ast.Name
+						if node.Variable != nil && node.Variable.Name != nil {
+							variableNameAST = node.Variable.Name
+							variableName = node.Variable.Name.Value
+						}
+						if nameAST, ok := knownVariableNames[variableName]; ok {
+							return reportError(
+								context,
+								fmt.Sprintf(`There can only be one variable named "%v".`, variableName),
+								[]ast.Node{nameAST, variableNameAST},
+							)
+						}
+						if variableNameAST != nil {
+							knownVariableNames[variableName] = variableNameAST
+						}
+					}
+					return visitor.ActionNoChange, nil
+				},
+			},
+		},
+	}
+	return &ValidationRuleInstance{
+		VisitorOpts: visitorOpts,
+	}
+}
+
 /**
  * VariablesAreInputTypesRule
  * Variables are input types

rules_unique_variable_names_test.go

@@ -0,0 +1,28 @@
+package graphql_test
+
+import (
+	"testing"
+
+	"github.com/graphql-go/graphql"
+	"github.com/graphql-go/graphql/gqlerrors"
+	"github.com/graphql-go/graphql/testutil"
+)
+
+func TestValidate_UniqueVariableNames_UniqueVariableNames(t *testing.T) {
+	testutil.ExpectPassesRule(t, graphql.UniqueVariableNamesRule, `
+      query A($x: Int, $y: String) { __typename }
+      query B($x: String, $y: Int) { __typename }
+    `)
+}
+func TestValidate_UniqueVariableNames_DuplicateVariableNames(t *testing.T) {
+	testutil.ExpectFailsRule(t, graphql.UniqueVariableNamesRule, `
+      query A($x: Int, $x: Int, $x: String) { __typename }
+      query B($x: String, $x: Int) { __typename }
+      query C($x: Int, $x: Int) { __typename }
+    `, []gqlerrors.FormattedError{
+		testutil.RuleError(`There can only be one variable named "x".`, 2, 16, 2, 25),
+		testutil.RuleError(`There can only be one variable named "x".`, 2, 16, 2, 34),
+		testutil.RuleError(`There can only be one variable named "x".`, 3, 16, 3, 28),
+		testutil.RuleError(`There can only be one variable named "x".`, 4, 16, 4, 25),
+	})
+}