1 files changed, 23 insertions, 0 deletions
diff --git a/vendor/github.com/vektah/gqlparser/validator/rules/unique_variable_names.go b/vendor/github.com/vektah/gqlparser/validator/rules/unique_variable_names.go
new file mode 100644
index 00000000..70590a88
--- /dev/null
+++ b/vendor/github.com/vektah/gqlparser/validator/rules/unique_variable_names.go
@@ -0,0 +1,23 @@
+package validator
+
+import (
+	"github.com/vektah/gqlparser/ast"
+	. "github.com/vektah/gqlparser/validator"
+)
+
+func init() {
+	AddRule("UniqueVariableNames", func(observers *Events, addError AddErrFunc) {
+		observers.OnOperation(func(walker *Walker, operation *ast.OperationDefinition) {
+			seen := map[string]bool{}
+			for _, def := range operation.VariableDefinitions {
+				if seen[def.Variable] {
+					addError(
+						Message(`There can be only one variable named "%s".`, def.Variable),
+						At(def.Position),
+					)
+				}
+				seen[def.Variable] = true
+			}
+		})
+	})
+}