[CodeGenLib] Add avialability gurads in generated code

Sources/GRPCCodeGen/Internal/Renderer/TextBasedRenderer.swift

@@ -818,6 +818,8 @@ struct TextBasedRenderer: RendererProtocol {
       renderCommentableDeclaration(comment: comment, declaration: nestedDeclaration)
     case let .deprecated(deprecation, nestedDeclaration):
       renderDeprecatedDeclaration(deprecation: deprecation, declaration: nestedDeclaration)
+    case let .guarded(availability, nestedDeclaration):
+      renderGuardedDeclaration(availability: availability, declaration: nestedDeclaration)
     case .variable(let variableDescription): renderVariable(variableDescription)
     case .extension(let extensionDescription): renderExtension(extensionDescription)
     case .struct(let structDescription): renderStruct(structDescription)
@@ -1074,6 +1076,21 @@ struct TextBasedRenderer: RendererProtocol {
     writer.writeLine(line)
   }
 
+  /// Renders the specified declaration with an availability guard annotation.
+  func renderGuardedDeclaration(availability: AvailabilityDescription, declaration: Declaration) {
+    renderAvailability(availability)
+    renderDeclaration(declaration)
+  }
+
+  func renderAvailability(_ availability: AvailabilityDescription) {
+    var line = "@available("
+    for osVersion in availability.osVersions {
+      line.append("\(osVersion.os.name) \(osVersion.version), ")
+    }
+    line.append("*)")
+    writer.writeLine(line)
+  }
+
   /// Renders the specified code block item.
   func renderCodeBlockItem(_ description: CodeBlockItem) {
     switch description {

Sources/GRPCCodeGen/Internal/StructuredSwiftRepresentation.swift

@@ -764,6 +764,9 @@ indirect enum Declaration: Equatable, Codable {
   /// A declaration that adds a comment on top of the provided declaration.
   case deprecated(DeprecationDescription, Declaration)
 
+  /// A declaration that adds an availability guard on top of the provided declaration.
+  case guarded(AvailabilityDescription, Declaration)
+
   /// A variable declaration.
   case variable(VariableDescription)
 
@@ -801,6 +804,42 @@ struct DeprecationDescription: Equatable, Codable {
   var renamed: String?
 }
 
+/// A description of an availability guard.
+///
+/// For example: `@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)`
+struct AvailabilityDescription: Equatable, Codable {
+  /// The array of OSes and versions which are specified in the availability guard.
+  var osVersions: [OSVersion]
+  init(osVersions: [OSVersion]) {
+    self.osVersions = osVersions
+  }
+
+  /// An OS and its version.
+  struct OSVersion: Equatable, Codable {
+    var os: OS
+    var version: String
+    init(os: OS, version: String) {
+      self.os = os
+      self.version = version
+    }
+  }
+
+  /// One of the possible OSes.
+  // swift-format-ignore: DontRepeatTypeInStaticProperties
+  struct OS: Equatable, Codable {
+    var name: String
+
+    init(name: String) {
+      self.name = name
+    }
+
+    static let macOS = Self(name: "macOS")
+    static let iOS = Self(name: "iOS")
+    static let watchOS = Self(name: "watchOS")
+    static let tvOS = Self(name: "tvOS")
+  }
+}
+
 /// A description of an assignment expression.
 ///
 /// For example: `foo = 42`.
@@ -1803,6 +1842,7 @@ extension Declaration {
       switch self {
       case .commentable(_, let declaration): return declaration.accessModifier
       case .deprecated(_, let declaration): return declaration.accessModifier
+      case .guarded(_, let declaration): return declaration.accessModifier
       case .variable(let variableDescription): return variableDescription.accessModifier
       case .extension(let extensionDescription): return extensionDescription.accessModifier
       case .struct(let structDescription): return structDescription.accessModifier
@@ -1821,6 +1861,9 @@ extension Declaration {
       case .deprecated(let deprecationDescription, var declaration):
         declaration.accessModifier = newValue
         self = .deprecated(deprecationDescription, declaration)
+      case .guarded(let availability, var declaration):
+        declaration.accessModifier = newValue
+        self = .guarded(availability, declaration)
       case .variable(var variableDescription):
         variableDescription.accessModifier = newValue
         self = .variable(variableDescription)

Sources/GRPCCodeGen/Internal/Translator/ClientCodeTranslator.swift

@@ -332,12 +332,15 @@ extension ClientCodeTranslator {
       )
     }
 
-    return .struct(
-      StructDescription(
-        accessModifier: self.accessModifier,
-        name: "\(service.namespacedGeneratedName)Client",
-        conformances: ["\(service.namespacedTypealiasGeneratedName).ClientProtocol"],
-        members: [clientProperty, initializer] + methods
+    return .guarded(
+      self.availabilityGuard,
+      .struct(
+        StructDescription(
+          accessModifier: self.accessModifier,
+          name: "\(service.namespacedGeneratedName)Client",
+          conformances: ["\(service.namespacedTypealiasGeneratedName).ClientProtocol"],
+          members: [clientProperty, initializer] + methods
+        )
       )
     )
   }

Sources/GRPCCodeGen/Internal/Translator/ServerCodeTranslator.swift

@@ -125,7 +125,10 @@ extension ServerCodeTranslator {
       )
     )
 
-    return .commentable(.preFormatted(service.documentation), streamingProtocol)
+    return .commentable(
+      .preFormatted(service.documentation),
+      .guarded(self.availabilityGuard, streamingProtocol)
+    )
   }
 
   private func makeStreamingMethodSignature(
@@ -188,7 +191,10 @@ extension ServerCodeTranslator {
       ]
     )
     let registerRPCsBody = self.makeRegisterRPCsMethodBody(for: service, in: codeGenerationRequest)
-    return .function(signature: registerRPCsSignature, body: registerRPCsBody)
+    return .guarded(
+      self.availabilityGuard,
+      .function(signature: registerRPCsSignature, body: registerRPCsBody)
+    )
   }
 
   private func makeRegisterRPCsMethodBody(

Sources/GRPCCodeGen/Internal/Translator/SpecializedTranslator.swift

@@ -46,4 +46,13 @@ extension SpecializedTranslator {
       }
     }
   }
+
+  internal var availabilityGuard: AvailabilityDescription {
+    AvailabilityDescription(osVersions: [
+      .init(os: .macOS, version: "13.0"),
+      .init(os: .iOS, version: "16.0"),
+      .init(os: .watchOS, version: "9.0"),
+      .init(os: .tvOS, version: "16.0"),
+    ])
+  }
 }

Tests/GRPCCodeGenTests/Internal/Renderer/TextBasedRendererTests.swift

@@ -667,6 +667,21 @@ final class Test_TextBasedRenderer: XCTestCase {
     )
   }
 
+  func testAvailability() throws {
+    try _test(
+      .init(osVersions: [
+        .init(os: .macOS, version: "12.0"),
+        .init(os: .iOS, version: "13.1.2"),
+        .init(os: .watchOS, version: "8.1.2"),
+        .init(os: .tvOS, version: "15.0.2"),
+      ]),
+      renderedBy: TextBasedRenderer.renderAvailability,
+      rendersAs: #"""
+        @available(macOS 12.0, iOS 13.1.2, watchOS 8.1.2, tvOS 15.0.2, *)
+        """#
+    )
+  }
+
   func testBindingKind() throws {
     try _test(
       .var,

Tests/GRPCCodeGenTests/Internal/Translator/ClientCodeTranslatorSnippetBasedTests.swift

@@ -66,6 +66,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
           }
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public struct NamespaceA_ServiceAClient: NamespaceA.ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -139,6 +140,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
           }
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public struct NamespaceA_ServiceAClient: NamespaceA.ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -212,6 +214,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
           }
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public struct NamespaceA_ServiceAClient: NamespaceA.ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -285,6 +288,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
           }
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public struct NamespaceA_ServiceAClient: NamespaceA.ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -386,6 +390,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
           }
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       package struct NamespaceA_ServiceAClient: NamespaceA.ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -475,6 +480,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
           }
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       internal struct ServiceAClient: ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -535,6 +541,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
       extension NamespaceA.ServiceA.ClientProtocol {
       }
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public struct NamespaceA_ServiceAClient: NamespaceA.ServiceA.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 
@@ -551,6 +558,7 @@ final class ClientCodeTranslatorSnippetBasedTests: XCTestCase {
       /// Documentation for ServiceB
       ///
       /// Line 2
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public struct ServiceBClient: ServiceB.ClientProtocol {
           private let client: GRPCCore.GRPCClient
 

Tests/GRPCCodeGenTests/Internal/Translator/IDLToStructuredSwiftTranslatorSnippetBasedTests.swift

@@ -181,10 +181,12 @@ final class IDLToStructuredSwiftTranslatorSnippetBasedTests: XCTestCase {
       }
 
       /// Documentation for AService
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {}
 
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           public func registerMethods(with router: inout GRPCCore.RPCRouter) {}
       }
 

Tests/GRPCCodeGenTests/Internal/Translator/ServerCodeTranslatorSnippetBasedTests.swift

@@ -51,12 +51,14 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {
           /// Documentation for unaryMethod
           func unary(request: ServerRequest.Stream<NamespaceA.ServiceA.Method.Unary.Input>) async throws -> ServerResponse.Stream<NamespaceA.ServiceA.Method.Unary.Output>
       }
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           public func registerMethods(with router: inout GRPCCore.RPCRouter) {
               router.registerHandler(
                   forMethod: NamespaceA.ServiceA.Method.Unary.descriptor,
@@ -115,12 +117,14 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       package protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {
           /// Documentation for inputStreamingMethod
           func inputStreaming(request: ServerRequest.Stream<NamespaceA.ServiceA.Method.InputStreaming.Input>) async throws -> ServerResponse.Stream<NamespaceA.ServiceA.Method.InputStreaming.Output>
       }
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           package func registerMethods(with router: inout GRPCCore.RPCRouter) {
               router.registerHandler(
                   forMethod: NamespaceA.ServiceA.Method.InputStreaming.descriptor,
@@ -183,12 +187,14 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {
           /// Documentation for outputStreamingMethod
           func outputStreaming(request: ServerRequest.Stream<NamespaceA.ServiceA.Method.OutputStreaming.Input>) async throws -> ServerResponse.Stream<NamespaceA.ServiceA.Method.OutputStreaming.Output>
       }
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           public func registerMethods(with router: inout GRPCCore.RPCRouter) {
               router.registerHandler(
                   forMethod: NamespaceA.ServiceA.Method.OutputStreaming.descriptor,
@@ -251,12 +257,14 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       package protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {
           /// Documentation for bidirectionalStreamingMethod
           func bidirectionalStreaming(request: ServerRequest.Stream<NamespaceA.ServiceA.Method.BidirectionalStreaming.Input>) async throws -> ServerResponse.Stream<NamespaceA.ServiceA.Method.BidirectionalStreaming.Output>
       }
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           package func registerMethods(with router: inout GRPCCore.RPCRouter) {
               router.registerHandler(
                   forMethod: NamespaceA.ServiceA.Method.BidirectionalStreaming.descriptor,
@@ -327,6 +335,7 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       internal protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {
           /// Documentation for inputStreamingMethod
           func inputStreaming(request: ServerRequest.Stream<NamespaceA.ServiceA.Method.InputStreaming.Input>) async throws -> ServerResponse.Stream<NamespaceA.ServiceA.Method.InputStreaming.Output>
@@ -336,6 +345,7 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
       }
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           internal func registerMethods(with router: inout GRPCCore.RPCRouter) {
               router.registerHandler(
                   forMethod: NamespaceA.ServiceA.Method.InputStreaming.descriptor,
@@ -406,12 +416,14 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       internal protocol ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {
           /// Documentation for MethodA
           func methodA(request: ServerRequest.Stream<ServiceA.Method.MethodA.Input>) async throws -> ServerResponse.Stream<ServiceA.Method.MethodA.Output>
       }
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           internal func registerMethods(with router: inout GRPCCore.RPCRouter) {
               router.registerHandler(
                   forMethod: ServiceA.Method.MethodA.descriptor,
@@ -468,9 +480,11 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
     let expectedSwift =
       """
       /// Documentation for ServiceA
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public protocol NamespaceA_ServiceAStreamingServiceProtocol: GRPCCore.RegistrableRPCService {}
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceA.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           public func registerMethods(with router: inout GRPCCore.RPCRouter) {}
       }
       /// Documentation for ServiceA
@@ -479,9 +493,11 @@ final class ServerCodeTranslatorSnippetBasedTests: XCTestCase {
       extension NamespaceA.ServiceA.ServiceProtocol {
       }
       /// Documentation for ServiceB
+      @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
       public protocol NamespaceA_ServiceBStreamingServiceProtocol: GRPCCore.RegistrableRPCService {}
       /// Conformance to `GRPCCore.RegistrableRPCService`.
       extension NamespaceA.ServiceB.StreamingServiceProtocol {
+          @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
           public func registerMethods(with router: inout GRPCCore.RPCRouter) {}
       }
       /// Documentation for ServiceB