feat: Adds UniqueFieldDefinitionNamesRule

Author: NeedleInAJayStack

Sources/GraphQL/Validation/Rules/UniqueFieldDefinitionNamesRule.swift

@@ -0,0 +1,113 @@
+
+/**
+ * Unique field definition names
+ *
+ * A GraphQL complex type is only valid if all its fields are uniquely named.
+ */
+func UniqueFieldDefinitionNamesRule(
+    context: SDLValidationContext
+) -> Visitor {
+    let schema = context.getSchema()
+    let existingTypeMap = schema?.typeMap ?? [:]
+    var knownFieldNames = [String: [String: Name]]()
+
+    return Visitor(
+        enter: { node, _, _, _, _ in
+            if let node = node as? InputObjectTypeDefinition {
+                checkFieldUniqueness(name: node.name, fields: node.fields)
+            } else if let node = node as? InputObjectExtensionDefinition {
+                checkFieldUniqueness(name: node.name, fields: node.definition.fields)
+            } else if let node = node as? InterfaceTypeDefinition {
+                checkFieldUniqueness(name: node.name, fields: node.fields)
+            } else if let node = node as? InterfaceExtensionDefinition {
+                checkFieldUniqueness(name: node.name, fields: node.definition.fields)
+            } else if let node = node as? ObjectTypeDefinition {
+                checkFieldUniqueness(name: node.name, fields: node.fields)
+            } else if let node = node as? TypeExtensionDefinition {
+                checkFieldUniqueness(name: node.name, fields: node.definition.fields)
+            }
+            return .continue
+        }
+    )
+
+    func checkFieldUniqueness(
+        name: Name,
+        fields: [FieldDefinition]
+    ) {
+        let typeName = name.value
+        var fieldNames = knownFieldNames[typeName] ?? [String: Name]()
+        let fieldNodes = fields
+        for fieldDef in fieldNodes {
+            let fieldName = fieldDef.name.value
+            if
+                let existingType = existingTypeMap[typeName],
+                hasField(type: existingType, fieldName: fieldName)
+            {
+                context.report(
+                    error: GraphQLError(
+                        message: "Field \"\(typeName).\(fieldName)\" already exists in the schema. It cannot also be defined in this type extension.",
+                        nodes: [fieldDef.name]
+                    )
+                )
+                continue
+            }
+            if let knownFieldName = fieldNames[fieldName] {
+                context.report(
+                    error: GraphQLError(
+                        message: "Field \"\(typeName).\(fieldName)\" can only be defined once.",
+                        nodes: [knownFieldName, fieldDef.name]
+                    )
+                )
+            } else {
+                fieldNames[fieldName] = fieldDef.name
+            }
+        }
+        knownFieldNames[typeName] = fieldNames
+    }
+
+    func checkFieldUniqueness(
+        name: Name,
+        fields: [InputValueDefinition]
+    ) {
+        let typeName = name.value
+        var fieldNames = knownFieldNames[typeName] ?? [String: Name]()
+        let fieldNodes = fields
+        for fieldDef in fieldNodes {
+            let fieldName = fieldDef.name.value
+            if
+                let existingType = existingTypeMap[typeName],
+                hasField(type: existingType, fieldName: fieldName)
+            {
+                context.report(
+                    error: GraphQLError(
+                        message: "Field \"\(typeName).\(fieldName)\" already exists in the schema. It cannot also be defined in this type extension.",
+                        nodes: [fieldDef.name]
+                    )
+                )
+                continue
+            }
+            if let knownFieldName = fieldNames[fieldName] {
+                context.report(
+                    error: GraphQLError(
+                        message: "Field \"\(typeName).\(fieldName)\" can only be defined once.",
+                        nodes: [knownFieldName, fieldDef.name]
+                    )
+                )
+            } else {
+                fieldNames[fieldName] = fieldDef.name
+            }
+        }
+        knownFieldNames[typeName] = fieldNames
+    }
+}
+
+func hasField(type: GraphQLNamedType, fieldName: String) -> Bool {
+    if let type = type as? GraphQLObjectType {
+        return (try? type.getFields()[fieldName]) != nil
+    } else if let type = type as? GraphQLInterfaceType {
+        return (try? type.getFields()[fieldName]) != nil
+    } else if let type = type as? GraphQLInputObjectType {
+        return (try? type.getFields()[fieldName]) != nil
+    }
+    return false
+}

Sources/GraphQL/Validation/SpecifiedRules.swift

@@ -41,7 +41,7 @@ public let specifiedSDLRules: [SDLValidationRule] = [
     UniqueOperationTypesRule,
     UniqueTypeNamesRule,
     UniqueEnumValueNamesRule,
-//    UniqueFieldDefinitionNamesRule,
+    UniqueFieldDefinitionNamesRule,
 //    UniqueArgumentDefinitionNamesRule,
 //    UniqueDirectiveNamesRule,
     KnownTypeNamesRule,