apple · madsodgaard · Mar 6, 2026 · Mar 7, 2026 · Mar 7, 2026 · Mar 7, 2026
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -101,3 +101,32 @@ jobs:
       windows_6_2_enabled: true
       windows_nightly_next_enabled: true
       windows_nightly_main_enabled: true
+
+  construct-linkage-test-matrix:
+    name: Construct linkage matrix
+    runs-on: ubuntu-latest
+    outputs:
+      linkage-test-matrix: '${{ steps.generate-matrix.outputs.linkage-test-matrix }}'
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - id: generate-matrix
+        run: echo "linkage-test-matrix=$(curl -s https://raw.githubusercontent.com/apple/swift-nio/main/scripts/generate_matrix.sh | bash)" >> "$GITHUB_OUTPUT"
+        env:
+          MATRIX_LINUX_SETUP_COMMAND: apt-get update -y && apt-get install -yq jq && git config --global --add safe.directory /swift-openapi-generator
+          MATRIX_LINUX_COMMAND: ./scripts/run-linkage-test.sh
+          MATRIX_LINUX_5_10_ENABLED: false
+          MATRIX_LINUX_6_0_ENABLED: false
+          MATRIX_LINUX_6_1_ENABLED: false
+          MATRIX_LINUX_NIGHTLY_NEXT_ENABLED: false
+          MATRIX_LINUX_NIGHTLY_MAIN_ENABLED: false
+
+  linkage-test:
+    name: Linkage test
+    needs: construct-linkage-test-matrix
+    uses: apple/swift-nio/.github/workflows/swift_test_matrix.yml@main
+    with:
+      name: "Linkage test"
+      matrix_string: '${{ needs.construct-linkage-test-matrix.outputs.linkage-test-matrix }}'
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
@@ -127,3 +127,32 @@ jobs:
       windows_6_2_enabled: true
       windows_nightly_next_enabled: true
       windows_nightly_main_enabled: true
+
+  construct-linkage-test-matrix:
+    name: Construct linkage matrix
+    runs-on: ubuntu-latest
+    outputs:
+      linkage-test-matrix: '${{ steps.generate-matrix.outputs.linkage-test-matrix }}'
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - id: generate-matrix
+        run: echo "linkage-test-matrix=$(curl -s https://raw.githubusercontent.com/apple/swift-nio/main/scripts/generate_matrix.sh | bash)" >> "$GITHUB_OUTPUT"
+        env:
+          MATRIX_LINUX_SETUP_COMMAND: apt-get update -y && apt-get install -yq jq && git config --global --add safe.directory /swift-openapi-generator
+          MATRIX_LINUX_COMMAND: ./scripts/run-linkage-test.sh
+          MATRIX_LINUX_5_10_ENABLED: false
+          MATRIX_LINUX_6_0_ENABLED: false
+          MATRIX_LINUX_6_1_ENABLED: false
+          MATRIX_LINUX_NIGHTLY_NEXT_ENABLED: false
+          MATRIX_LINUX_NIGHTLY_MAIN_ENABLED: false
+
+  linkage-test:
+    name: Linkage test
+    needs: construct-linkage-test-matrix
+    uses: apple/swift-nio/.github/workflows/swift_test_matrix.yml@main
+    with:
+      name: "Linkage test"
+      matrix_string: '${{ needs.construct-linkage-test-matrix.outputs.linkage-test-matrix }}'
diff --git a/Package.swift b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.10
+// swift-tools-version:6.1
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the SwiftOpenAPIGenerator open source project
@@ -54,7 +54,7 @@ let package = Package(
         // Tests-only: Runtime library linked by generated code, and also
         // helps keep the runtime library new enough to work with the generated
         // code.
-        .package(url: "https://github.com/apple/swift-openapi-runtime", from: "1.8.2"),
+        .package(url: "https://github.com/apple/swift-openapi-runtime", from: "1.11.0", traits: []),
         .package(url: "https://github.com/apple/swift-http-types", from: "1.0.2"),
     ],
     targets: [

diff --git a/Package@swift-5.10.swift b/Package@swift-5.10.swift
@@ -0,0 +1,167 @@
+// swift-tools-version:5.10
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2023 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+import Foundation
+import PackageDescription
+
+// General Swift-settings for all targets.
+var swiftSettings: [SwiftSetting] = [
+    // https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md
+    // Require `any` for existential types.
+    .enableUpcomingFeature("ExistentialAny"), .enableExperimentalFeature("StrictConcurrency=complete"),
+]
+
+let package = Package(
+    name: "swift-openapi-generator",
+    platforms: [
+        .macOS(.v10_15),
+
+        // The platforms below are not currently supported for running
+        // the generator itself. We include them here to allow the generator
+        // to emit a more descriptive compiler error.
+        .iOS(.v13), .tvOS(.v13), .watchOS(.v6), .visionOS(.v1),
+    ],
+    products: [
+        .executable(name: "swift-openapi-generator", targets: ["swift-openapi-generator"]),
+        .plugin(name: "OpenAPIGenerator", targets: ["OpenAPIGenerator"]),
+        .plugin(name: "OpenAPIGeneratorCommand", targets: ["OpenAPIGeneratorCommand"]),
+        .library(name: "_OpenAPIGeneratorCore", targets: ["_OpenAPIGeneratorCore"]),
+    ],
+    dependencies: [
+
+        // General algorithms
+        .package(url: "https://github.com/apple/swift-algorithms", from: "1.2.0"),
+        .package(url: "https://github.com/apple/swift-collections", from: "1.1.4"),
+
+        // Read OpenAPI documents
+        .package(url: "https://github.com/mattpolzin/OpenAPIKit", from: "3.9.0"),
+        .package(url: "https://github.com/jpsim/Yams", "4.0.0"..<"7.0.0"),
+
+        // CLI Tool
+        .package(url: "https://github.com/apple/swift-argument-parser", from: "1.3.0"),
+
+        // Tests-only: Runtime library linked by generated code, and also
+        // helps keep the runtime library new enough to work with the generated
+        // code.
+        .package(url: "https://github.com/apple/swift-openapi-runtime", from: "1.8.2"),
+        .package(url: "https://github.com/apple/swift-http-types", from: "1.0.2"),
+    ],
+    targets: [
+
+        // Generator Core
+        .target(
+            name: "_OpenAPIGeneratorCore",
+            dependencies: [
+                .product(name: "OpenAPIKit", package: "OpenAPIKit"),
+                .product(name: "OpenAPIKit30", package: "OpenAPIKit"),
+                .product(name: "OpenAPIKitCompat", package: "OpenAPIKit"),
+                .product(name: "Algorithms", package: "swift-algorithms"),
+                .product(name: "OrderedCollections", package: "swift-collections"),
+                .product(name: "Yams", package: "Yams"),
+            ],
+            swiftSettings: swiftSettings
+        ),
+
+        // Generator Core Tests
+        .testTarget(
+            name: "OpenAPIGeneratorCoreTests",
+            dependencies: ["_OpenAPIGeneratorCore"],
+            swiftSettings: swiftSettings
+        ),
+
+        // GeneratorReferenceTests
+        .testTarget(
+            name: "OpenAPIGeneratorReferenceTests",
+            dependencies: ["_OpenAPIGeneratorCore"],
+            resources: [.copy("Resources")],
+            swiftSettings: swiftSettings
+        ),
+
+        // Common types for concrete PetstoreConsumer*Tests test targets.
+        .target(
+            name: "PetstoreConsumerTestCore",
+            dependencies: [
+                .product(name: "OpenAPIRuntime", package: "swift-openapi-runtime"),
+                .product(name: "HTTPTypes", package: "swift-http-types"),
+            ],
+            swiftSettings: swiftSettings
+        ),
+
+        // PetstoreConsumerTests
+        // Builds and tests the reference code from GeneratorReferenceTests
+        // to ensure it actually works correctly at runtime.
+        .testTarget(
+            name: "PetstoreConsumerTests",
+            dependencies: ["PetstoreConsumerTestCore"],
+            swiftSettings: swiftSettings
+        ),
+
+        // Test Target for swift-openapi-generator
+        .testTarget(
+            name: "OpenAPIGeneratorTests",
+            dependencies: [
+                "_OpenAPIGeneratorCore",
+                // Everything except windows: https://github.com/swiftlang/swift-package-manager/issues/6367
+                .target(
+                    name: "swift-openapi-generator",
+                    condition: .when(platforms: [.android, .linux, .macOS, .openbsd, .wasi, .custom("freebsd")])
+                ), .product(name: "ArgumentParser", package: "swift-argument-parser"),
+            ],
+            resources: [.copy("Resources")],
+            swiftSettings: swiftSettings
+        ),
+
+        // Generator CLI
+        .executableTarget(
+            name: "swift-openapi-generator",
+            dependencies: [
+                "_OpenAPIGeneratorCore", .product(name: "ArgumentParser", package: "swift-argument-parser"),
+            ],
+            swiftSettings: swiftSettings
+        ),
+
+        // Build Plugin
+        .plugin(name: "OpenAPIGenerator", capability: .buildTool(), dependencies: ["swift-openapi-generator"]),
+
+        // Command Plugin
+        .plugin(
+            name: "OpenAPIGeneratorCommand",
+            capability: .command(
+                intent: .custom(
+                    verb: "generate-code-from-openapi",
+                    description: "Generate Swift code from an OpenAPI document."
+                ),
+                permissions: [
+                    .writeToPackageDirectory(
+                        reason: "To write the generated Swift files back into the source directory of the package."
+                    )
+                ]
+            ),
+            dependencies: ["swift-openapi-generator"]
+        ),
+    ]
+)
+
+// ---    STANDARD CROSS-REPO SETTINGS DO NOT EDIT   --- //
+for target in package.targets {
+    switch target.type {
+    case .regular, .test, .executable:
+        var settings = target.swiftSettings ?? []
+        // https://github.com/swiftlang/swift-evolution/blob/main/proposals/0444-member-import-visibility.md
+        settings.append(.enableUpcomingFeature("MemberImportVisibility"))
+        target.swiftSettings = settings
+    case .macro, .plugin, .system, .binary: ()  // not applicable
+    @unknown default: ()  // we don't know what to do here, do nothing
+    }
+}// --- END: STANDARD CROSS-REPO SETTINGS DO NOT EDIT --- //
diff --git a/Sources/_OpenAPIGeneratorCore/Layers/StructuredSwiftRepresentation.swift b/Sources/_OpenAPIGeneratorCore/Layers/StructuredSwiftRepresentation.swift
@@ -12,6 +12,24 @@
 //
 //===----------------------------------------------------------------------===//
 
+/// A top-level import statement, that may be conditional based on a compile-time condition
+enum ImportStatement: Equatable, Codable {
+    /// Imports based on compile time condition
+    case conditional(
+        condition: Condition,
+        thenImportDescription: ImportDescription,
+        elseImportDescription: ImportDescription
+    )
+
+    /// Always imported
+    case always(ImportDescription)
+
+    enum Condition: Equatable, Codable {
+        /// A condition on whether we can import a specific module
+        case canImport(String)
+    }
+}
+
 /// A description of an import declaration.
 ///
 /// For example: `import Foo`.
@@ -678,6 +696,9 @@ indirect enum Declaration: Equatable, Codable {
 
     /// An enum case declaration.
     case enumCase(EnumCaseDescription)
+
+    /// A #if canImport declaration
+    case canImportConditional(String, then: [Declaration], else: [Declaration])
 }
 
 /// A description of a deprecation notice.
@@ -1052,7 +1073,7 @@ struct FileDescription: Equatable, Codable {
 
     /// Import statements placed below the top comment, but before the code
     /// blocks.
-    var imports: [ImportDescription]?
+    var imports: [ImportStatement]?
 
     /// The code blocks that represent the main contents of the file.
     var codeBlocks: [CodeBlock]
@@ -1675,6 +1696,7 @@ extension Declaration {
             case .protocol(let protocolDescription): return protocolDescription.accessModifier
             case .function(let functionDescription): return functionDescription.signature.accessModifier
             case .enumCase: return nil
+            case .canImportConditional: return nil
             }
         }
         set {
@@ -1707,6 +1729,7 @@ extension Declaration {
                 functionDescription.signature.accessModifier = newValue
                 self = .function(functionDescription)
             case .enumCase: break
+            case .canImportConditional: break
             }
         }
     }

diff --git a/Sources/_OpenAPIGeneratorCore/Renderer/TextBasedRenderer.swift b/Sources/_OpenAPIGeneratorCore/Renderer/TextBasedRenderer.swift
@@ -145,10 +145,34 @@ struct TextBasedRenderer: RendererProtocol {
     }
 
     /// Renders the specified import statements.
-    func renderImports(_ imports: [ImportDescription]?) { (imports ?? []).forEach(renderImport) }
+    func renderImports(_ imports: [ImportStatement]?) { (imports ?? []).forEach(renderImport) }
 
     /// Renders a single import statement.
-    func renderImport(_ description: ImportDescription) {
+    func renderImport(_ importStatement: ImportStatement) {
+        switch importStatement {
+        case .conditional(let condition, let thenImportDescription, let elseImportDescription):
+            writer.writeLine("#if \(renderImportCondition(condition))")
+            renderImport(thenImportDescription)
+            writer.writeLine("#else")
+            renderImport(elseImportDescription)
+            writer.writeLine("#endif")
+
+        case .always(let importDescription): self.renderImport(importDescription)
+        }
+    }
+
+    /// Renders a import condition
+    func renderImportCondition(_ condition: ImportStatement.Condition) -> String {
+        switch condition {
+        case .canImport(let argument): "canImport(\(argument))"
+        }
+    }
+
+    /// Renders the specified import statements.
+    private func renderImports(_ imports: [ImportDescription]?) { (imports ?? []).forEach(renderImport) }
+
+    /// Renders a single import statement.
+    private func renderImport(_ description: ImportDescription) {
         func render(preconcurrency: Bool) {
             let spiPrefix = description.spi.map { "@_spi(\($0)) " } ?? ""
             let preconcurrencyPrefix = preconcurrency ? "@preconcurrency " : ""
@@ -713,6 +737,8 @@ struct TextBasedRenderer: RendererProtocol {
         case .typealias(let typealiasDescription): renderTypealias(typealiasDescription)
         case .function(let functionDescription): renderFunction(functionDescription)
         case .enumCase(let enumCase): renderEnumCase(enumCase)
+        case .canImportConditional(let condition, let thenDecls, let elseDecls):
+            renderCanImportConditional(condition, thenDecls, elseDecls)
         }
     }
 
@@ -836,6 +862,15 @@ struct TextBasedRenderer: RendererProtocol {
         writer.writeLine(line)
     }
 
+    /// Renders a canImport with both then and else branches
+    func renderCanImportConditional(_ module: String, _ thenDecls: [Declaration], _ elseDecls: [Declaration]) {
+        writer.writeLine("#if canImport(\(module))")
+        for thenDecl in thenDecls { renderDeclaration(thenDecl) }
+        writer.writeLine("#else")
+        for elseDecl in elseDecls { renderDeclaration(elseDecl) }
+        writer.writeLine("#endif")
+    }
+
     /// Renders the specified code block item.
     func renderCodeBlockItem(_ description: CodeBlockItem) {
         switch description {

diff --git a/Sources/_OpenAPIGeneratorCore/Translator/ClientTranslator/ClientTranslator.swift b/Sources/_OpenAPIGeneratorCore/Translator/ClientTranslator/ClientTranslator.swift
@@ -35,7 +35,8 @@ struct ClientFileTranslator: FileTranslator {
         let topComment = self.topComment
 
         let imports =
-            Constants.File.clientServerImports + config.additionalImports.map { ImportDescription(moduleName: $0) }
+            Constants.File.clientServerImports
+            + config.additionalImports.map { .always(ImportDescription(moduleName: $0)) }
 
         let clientMethodDecls = try OperationDescription.all(from: doc.paths, in: components, context: context)
             .map(translateClientMethod(_:))
@@ -67,7 +68,7 @@ struct ClientFileTranslator: FileTranslator {
                 accessModifier: config.access,
                 kind: .initializer,
                 parameters: [
-                    .init(label: "serverURL", type: .init(TypeName.url)),
+                    .init(label: "serverURL", type: .init(TypeName.foundationURLTypeAlias)),
                     .init(
                         label: "configuration",
                         type: .member(Constants.Configuration.typeName),