fix: Selection set initializer reserved parameter name

Tests/ApolloCodegenTests/CodeGeneration/Templates/SelectionSet/SelectionSetTemplate_Initializers_Tests.swift

@@ -1757,7 +1757,7 @@ class SelectionSetTemplate_Initializers_Tests: XCTestCase {
     expect(actual).to(equalLineByLine(expected, atLine: 24, ignoringExtraLines: true))
   }
 
-  // MARK: - Include/Skip Tests
+  // MARK: Include/Skip Tests
 
   func test__render_given_fieldWithInclusionCondition_rendersInitializerWithOptionalParameter() async throws {
     // given
@@ -2136,4 +2136,110 @@ class SelectionSetTemplate_Initializers_Tests: XCTestCase {
     expect(allAnimals_ifA_actual).to(equalLineByLine(
       allAnimals_ifA_expected, atLine: 23, ignoringExtraLines: true))
   }
+
+  // MARK: Parameter Name Tests
+
+  func test__render__givenReservedFieldName_shouldGenerateParameterNameWithAlias() async throws {
+    // given
+    schemaSDL = """
+    type Query {
+      allAnimals: [Animal!]
+    }
+
+    type Animal {
+      name: String
+      self: String # <- reserved name
+    }
+    """
+
+    document = """
+    query TestOperation {
+      allAnimals {
+        name
+        self
+      }
+    }
+    """
+
+    let expected =
+    """
+      public init(
+        name: String? = nil,
+        `self` _self: String? = nil
+      ) {
+        self.init(_dataDict: DataDict(
+          data: [
+            "__typename": TestSchema.Objects.Animal.typename,
+            "name": name,
+            "self": _self,
+          ],
+          fulfilledFragments: [
+            ObjectIdentifier(TestOperationQuery.Data.AllAnimal.self)
+          ]
+        ))
+      }
+    """
+
+    // when
+    try await buildSubjectAndOperation()
+
+    let allAnimals = try XCTUnwrap(
+      operation[field: "query"]?[field: "allAnimals"]?.selectionSet
+    )
+
+    let actual = subject.test_render(childEntity: allAnimals.computed)
+
+    // then
+    expect(actual).to(equalLineByLine(expected, atLine: 18, ignoringExtraLines: true))
+  }
+
+  func test__render__givenFieldName_generatesParameterNameWithoutAlias() async throws {
+    // given
+    schemaSDL = """
+    type Query {
+      allAnimals: [Animal!]
+    }
+
+    type Animal {
+      name: String
+    }
+    """
+
+    document = """
+    query TestOperation {
+      allAnimals {
+        name
+      }
+    }
+    """
+
+    let expected =
+    """
+      public init(
+        name: String? = nil
+      ) {
+        self.init(_dataDict: DataDict(
+          data: [
+            "__typename": TestSchema.Objects.Animal.typename,
+            "name": name,
+          ],
+          fulfilledFragments: [
+            ObjectIdentifier(TestOperationQuery.Data.AllAnimal.self)
+          ]
+        ))
+      }
+    """
+
+    // when
+    try await buildSubjectAndOperation()
+
+    let allAnimals = try XCTUnwrap(
+      operation[field: "query"]?[field: "allAnimals"]?.selectionSet
+    )
+
+    let actual = subject.test_render(childEntity: allAnimals.computed)
+
+    // then
+    expect(actual).to(equalLineByLine(expected, atLine: 16, ignoringExtraLines: true))
+  }
 }

apollo-ios-codegen/Sources/ApolloCodegenLib/Templates/RenderingHelpers/String+SwiftNameEscaping.swift

@@ -34,25 +34,59 @@ extension String {
   private func escapeIf(in set: Set<String>) -> String {
     set.contains(self) ? "`\(self)`" : self
   }
-
-  /// Renders the string as the property name for a field accessor on a generated `SelectionSet`.
-  /// This escapes the names of properties that would conflict with Swift reserved keywords.
-  func renderAsFieldPropertyName(
-    config: ApolloCodegenConfiguration
-  ) -> String {
+
+  private func aliasIf(in set: Set<String>) -> String {
+    set.contains(self) ? "_\(self)" : self
+  }
+
+  private func escapeWithAliasIf(in set: Set<String>) -> String {
+    set.contains(self) ? "`\(self)` _\(self)" : self
+  }
+
+  private func renderedAsPropertyName(config: ApolloCodegenConfiguration) -> String {
     var propertyName = self
-    
+
     switch config.options.conversionStrategies.fieldAccessors {
     case .camelCase:
       propertyName = propertyName.convertToCamelCase()
     case .idiomatic:
       break
     }
-    
+
     propertyName = propertyName.isAllUppercased ? propertyName.lowercased() : propertyName.firstLowercased
-    return propertyName.escapeIf(in: SwiftKeywords.FieldAccessorNamesToEscape)
+    return propertyName
   }
-
+
+  /// Renders the string as the property name for a field accessor on a generated `SelectionSet`.
+  /// This escapes the names of properties that would conflict with Swift reserved keywords.
+  func renderAsFieldPropertyName(config: ApolloCodegenConfiguration) -> String {
+    let propertyName = renderedAsPropertyName(config: config)
+      .escapeIf(in: SwiftKeywords.FieldAccessorNamesToEscape)
+
+    return propertyName
+  }
+
+  /// Renders the string as the parameter name for an initializer on a generated `SelectionSet`.
+  /// This escapes the names of parameters that would conflict with Swift reserved keywords and
+  /// makes them available under a parameter name alias to avoid further conflicts; see issue #3330
+  /// as an example.
+  func renderAsInitializerParameterName(config: ApolloCodegenConfiguration) -> String {
+    let propertyName = renderedAsPropertyName(config: config)
+      .escapeWithAliasIf(in: SwiftKeywords.FieldAccessorNamesToEscape)
+
+    return propertyName
+  }
+
+  /// Renders the string as the parameter name for an initializer on a generated `SelectionSet`.
+  /// This underscores the names of initializer parameters that would conflict with Swift reserved
+  /// keywords; see issue #3330 as an example.
+  func renderAsInitializerParameterAccessorName(config: ApolloCodegenConfiguration) -> String {
+    let propertyName = renderedAsPropertyName(config: config)
+      .aliasIf(in: SwiftKeywords.FieldAccessorNamesToEscape)
+
+    return propertyName
+  }
+
   func renderAsInputObjectName(
     config: ApolloCodegenConfiguration
   ) -> String {

apollo-ios-codegen/Sources/ApolloCodegenLib/Templates/SelectionSetTemplate.swift

@@ -608,7 +608,8 @@ struct SelectionSetTemplate {
   ) -> TemplateString {
     let isOptional: Bool = field.type.isNullable || field.isConditionallyIncluded(in: scope)
     return """
-      \(field.responseKey.renderAsFieldPropertyName(config: config.config)): \(typeName(for: field, forceOptional: isOptional))\
+      \(field.responseKey.renderAsInitializerParameterName(config: config.config)): \
+      \(typeName(for: field, forceOptional: isOptional))\
       \(if: isOptional, " = nil")
       """
   }
@@ -641,7 +642,7 @@ struct SelectionSetTemplate {
     }()
 
     return """
-      "\(field.responseKey)": \(field.responseKey.renderAsFieldPropertyName(config: config.config))\
+      "\(field.responseKey)": \(field.responseKey.renderAsInitializerParameterAccessorName(config: config.config))\
       \(if: isEntityField, "._fieldData")
       """
   }