1 files changed, 69 insertions, 0 deletions
diff --git a/school/node_modules/graphql/validation/rules/UniqueEnumValueNamesRule.js.flow b/school/node_modules/graphql/validation/rules/UniqueEnumValueNamesRule.js.flow
new file mode 100644
index 0000000..09515e8
--- /dev/null
+++ b/school/node_modules/graphql/validation/rules/UniqueEnumValueNamesRule.js.flow
@@ -0,0 +1,69 @@
+// @flow strict
+import { GraphQLError } from '../../error/GraphQLError';
+
+import type { ASTVisitor } from '../../language/visitor';
+import type {
+  EnumTypeDefinitionNode,
+  EnumTypeExtensionNode,
+} from '../../language/ast';
+
+import { isEnumType } from '../../type/definition';
+
+import type { SDLValidationContext } from '../ValidationContext';
+
+/**
+ * Unique enum value names
+ *
+ * A GraphQL enum type is only valid if all its values are uniquely named.
+ */
+export function UniqueEnumValueNamesRule(
+  context: SDLValidationContext,
+): ASTVisitor {
+  const schema = context.getSchema();
+  const existingTypeMap = schema ? schema.getTypeMap() : Object.create(null);
+  const knownValueNames = Object.create(null);
+
+  return {
+    EnumTypeDefinition: checkValueUniqueness,
+    EnumTypeExtension: checkValueUniqueness,
+  };
+
+  function checkValueUniqueness(
+    node: EnumTypeDefinitionNode | EnumTypeExtensionNode,
+  ) {
+    const typeName = node.name.value;
+
+    if (!knownValueNames[typeName]) {
+      knownValueNames[typeName] = Object.create(null);
+    }
+
+    // istanbul ignore next (See: 'https://github.com/graphql/graphql-js/issues/2203')
+    const valueNodes = node.values ?? [];
+    const valueNames = knownValueNames[typeName];
+
+    for (const valueDef of valueNodes) {
+      const valueName = valueDef.name.value;
+
+      const existingType = existingTypeMap[typeName];
+      if (isEnumType(existingType) && existingType.getValue(valueName)) {
+        context.reportError(
+          new GraphQLError(
+            `Enum value "${typeName}.${valueName}" already exists in the schema. It cannot also be defined in this type extension.`,
+            valueDef.name,
+          ),
+        );
+      } else if (valueNames[valueName]) {
+        context.reportError(
+          new GraphQLError(
+            `Enum value "${typeName}.${valueName}" can only be defined once.`,
+            [valueNames[valueName], valueDef.name],
+          ),
+        );
+      } else {
+        valueNames[valueName] = valueDef.name;
+      }
+    }
+
+    return false;
+  }
+}