Enable the license header check

.flake8

@@ -2,3 +2,6 @@
 
 # Match the maximum line length in Swift files.
 max-line-length = 120
+
+# E265, E266 and conflict with the header expected by the license header check
+ignore = E265, E266

.github/workflows/pull_request.yml

@@ -12,6 +12,5 @@ jobs:
     name: Soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
     with:
-      license_header_check_enabled: false
       license_header_check_project_name: "Swift.org"
       api_breakage_check_allowlist_path: "api-breakages.txt"

.license_header_template

@@ -0,0 +1,11 @@
+@@===----------------------------------------------------------------------===@@
+@@
+@@ This source file is part of the Swift.org open source project
+@@
+@@ Copyright (c) YEARS Apple Inc. and the Swift project authors
+@@ Licensed under Apache License v2.0 with Runtime Library Exception
+@@
+@@ See https://swift.org/LICENSE.txt for license information
+@@ See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+@@
+@@===----------------------------------------------------------------------===@@

.licenseignore

@@ -0,0 +1,11 @@
+.flake8
+.gitignore
+.swiftci
+*.md
+*.txt
+*.yaml
+*.yml
+**/*.docc/**
+**/*.modulemap
+CODEOWNERS
+Package.swift

Plugins/FormatPlugin/plugin.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import Foundation
 import PackagePlugin
 

Plugins/LintPlugin/plugin.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import Foundation
 import PackagePlugin
 

Scripts/format-diff.sh

@@ -1,15 +1,15 @@
-#!/usr/bin/env bash
-#===----------------------------------------------------------------------===#
-#
-# This source file is part of the Swift.org open source project
-#
-# Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
-# Licensed under Apache License v2.0 with Runtime Library Exception
-#
-# See https://swift.org/LICENSE.txt for license information
-# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-#
-#===----------------------------------------------------------------------===#
+#!/bin/bash
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+##
+##===----------------------------------------------------------------------===##
 
 # SYNOPSIS
 #   format-diff.sh FILE [OPTION]...

Sources/_SwiftFormatTestSupport/DiagnosingTestCase.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 @_spi(Rules) @_spi(Testing) import SwiftFormat
 import SwiftSyntax

Tests/SwiftFormatPerformanceTests/WhitespaceLinterPerformanceTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 @_spi(Testing) import SwiftFormat
 import SwiftParser
 import SwiftSyntax

Tests/SwiftFormatTests/API/ConfigurationTests.swift

@@ -1,3 +1,14 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
 import SwiftFormat
 import XCTest
 

Tests/SwiftFormatTests/Core/DocumentationCommentTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import Markdown
 @_spi(Testing) import SwiftFormat
 import SwiftSyntax

Tests/SwiftFormatTests/Core/DocumentationCommentTextTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 @_spi(Testing) import SwiftFormat
 import SwiftSyntax
 import SwiftSyntaxBuilder

Tests/SwiftFormatTests/Core/RuleMaskTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 @_spi(Testing) import SwiftFormat
 import SwiftParser
 import SwiftSyntax

Tests/SwiftFormatTests/PrettyPrint/AccessorTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 final class AccessorTests: PrettyPrintTestCase {
   func testBasicAccessors() {
     let input =

Tests/SwiftFormatTests/PrettyPrint/ArrayDeclTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 import SwiftSyntax
 import _SwiftFormatTestSupport

Tests/SwiftFormatTests/PrettyPrint/AsExprTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import XCTest
 
 final class AsExprTests: PrettyPrintTestCase {

Tests/SwiftFormatTests/PrettyPrint/AssignmentExprTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 
 final class AssignmentExprTests: PrettyPrintTestCase {

Tests/SwiftFormatTests/PrettyPrint/AttributeTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 
 final class AttributeTests: PrettyPrintTestCase {

Tests/SwiftFormatTests/PrettyPrint/AvailabilityConditionTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 final class AvailabilityConditionTests: PrettyPrintTestCase {
   func testAvailabilityCondition() {
     let input =

Tests/SwiftFormatTests/PrettyPrint/AwaitExprTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 
 final class AwaitExprTests: PrettyPrintTestCase {

Tests/SwiftFormatTests/PrettyPrint/BackDeployAttributeTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 final class BackDeployAttributeTests: PrettyPrintTestCase {
   func testSpacingAndWrapping() {
     let input =

Tests/SwiftFormatTests/PrettyPrint/BacktickTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 final class BacktickTests: PrettyPrintTestCase {
   func testBackticks() {
     let input =

Tests/SwiftFormatTests/PrettyPrint/BinaryOperatorExprTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 
 final class BinaryOperatorExprTests: PrettyPrintTestCase {

Tests/SwiftFormatTests/PrettyPrint/ClassDeclTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 
 final class ClassDeclTests: PrettyPrintTestCase {

Tests/SwiftFormatTests/PrettyPrint/ClosureExprTests.swift

@@ -1,3 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import SwiftFormat
 
 final class ClosureExprTests: PrettyPrintTestCase {