[Infra] Remove Swift compiler(>=6) checks

FirebaseAuth/Sources/Swift/Backend/IdentityToolkitRequest.swift

@@ -19,15 +19,9 @@ private let kHttpProtocol = "http:"
 
 private let kEmulatorHostAndPrefixFormat = "%@/%@"
 
-#if compiler(>=6)
-  /// Host for server API calls. This should be changed via
-  /// `IdentityToolkitRequest.setHost(_ host:)` for testing purposes only.
-  private nonisolated(unsafe) var gAPIHost = "www.googleapis.com"
-#else
-  /// Host for server API calls. This should be changed via
-  /// `IdentityToolkitRequest.setHost(_ host:)` for testing purposes only.
-  private var gAPIHost = "www.googleapis.com"
-#endif // compiler(>=6)
+/// Host for server API calls. This should be changed via
+/// `IdentityToolkitRequest.setHost(_ host:)` for testing purposes only.
+private nonisolated(unsafe) var gAPIHost = "www.googleapis.com"
 
 private let kFirebaseAuthAPIHost = "www.googleapis.com"
 private let kIdentityPlatformAPIHost = "identitytoolkit.googleapis.com"

FirebaseAuth/Sources/Swift/Backend/RPC/SecureTokenRequest.swift

@@ -54,15 +54,9 @@ private let kRefreshTokenKey = "refreshToken"
 /// The key for the "code" parameter in the request.
 private let kCodeKey = "code"
 
-#if compiler(>=6)
-  /// Host for server API calls. This should be changed via
-  /// `SecureTokenRequest.setHost(_ host:)` for testing purposes only.
-  private nonisolated(unsafe) var gAPIHost = "securetoken.googleapis.com"
-#else
-  /// Host for server API calls. This should be changed via
-  /// `SecureTokenRequest.setHost(_ host:)` for testing purposes only.
-  private var gAPIHost = "securetoken.googleapis.com"
-#endif // compiler(>=6)
+/// Host for server API calls. This should be changed via
+/// `SecureTokenRequest.setHost(_ host:)` for testing purposes only.
+private nonisolated(unsafe) var gAPIHost = "securetoken.googleapis.com"
 
 /// Represents the parameters for the token endpoint.
 @available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)

FirebaseCore/Internal/Sources/HeartbeatLogging/HeartbeatStorage.swift

@@ -52,22 +52,9 @@ final class HeartbeatStorage: Sendable, HeartbeatStorageProtocol {
   // MARK: - Instance Management
 
   /// Statically allocated cache of `HeartbeatStorage` instances keyed by string IDs.
-  #if compiler(>=6)
-    // In Swift 6, this property is not concurrency-safe because it is
-    // nonisolated global shared mutable state. Because this target's
-    // deployment version does not support Swift concurrency, it is marked as
-    // `nonisolated(unsafe)` to disable concurrency-safety checks. The
-    // property's access is protected by an external synchronization mechanism
-    // (see `instancesLock` property).
-    private nonisolated(unsafe) static var cachedInstances: AtomicBox<
-      [String: WeakContainer<HeartbeatStorage>]
-    > = AtomicBox([:])
-  #else
-    // TODO(Xcode 16): Delete this block when minimum supported Xcode is
-    // Xcode 16.
-    static var cachedInstances: AtomicBox<[String: WeakContainer<HeartbeatStorage>]> =
-      AtomicBox([:])
-  #endif // compiler(>=6)
+  private nonisolated(unsafe) static var cachedInstances: AtomicBox<
+    [String: WeakContainer<HeartbeatStorage>]
+  > = AtomicBox([:])
 
   /// Gets an existing `HeartbeatStorage` instance with the given `id` if one exists. Otherwise,
   /// makes a new instance with the given `id`.

FirebaseFunctions/Sources/Functions.swift

@@ -82,12 +82,8 @@ enum FunctionsConstants {
 
   /// A map of active instances, grouped by app. Keys are FirebaseApp names and values are arrays
   /// containing all instances of Functions associated with the given app.
-  #if compiler(>=6.0)
-    private nonisolated(unsafe) static var instances: AtomicBox<[String: [Functions]]> =
-      AtomicBox([:])
-  #else
-    private static var instances: AtomicBox<[String: [Functions]]> = AtomicBox([:])
-  #endif
+  private nonisolated(unsafe) static var instances: AtomicBox<[String: [Functions]]> =
+    AtomicBox([:])
 
   /// The custom domain to use for all functions references (optional).
   let customDomain: String?
@@ -605,65 +601,34 @@ enum FunctionsConstants {
     }
   }
 
-  #if compiler(>=6.0)
-    @available(macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0, *)
-    private func callableStreamResult(fromResponseData data: Data,
-                                      endpointURL url: URL) throws -> sending JSONStreamResponse {
-      let data = try processedData(fromResponseData: data, endpointURL: url)
-
-      let responseJSONObject: Any
-      do {
-        responseJSONObject = try JSONSerialization.jsonObject(with: data)
-      } catch {
-        throw FunctionsError(.dataLoss, userInfo: [NSUnderlyingErrorKey: error])
-      }
-
-      guard let responseJSON = responseJSONObject as? [String: Any] else {
-        let userInfo = [NSLocalizedDescriptionKey: "Response was not a dictionary."]
-        throw FunctionsError(.dataLoss, userInfo: userInfo)
-      }
+  @available(macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0, *)
+  private func callableStreamResult(fromResponseData data: Data,
+                                    endpointURL url: URL) throws -> sending JSONStreamResponse {
+    let data = try processedData(fromResponseData: data, endpointURL: url)
 
-      if let _ = responseJSON["result"] {
-        return .result(responseJSON)
-      } else if let _ = responseJSON["message"] {
-        return .message(responseJSON)
-      } else {
-        throw FunctionsError(
-          .dataLoss,
-          userInfo: [NSLocalizedDescriptionKey: "Response is missing result or message field."]
-        )
-      }
+    let responseJSONObject: Any
+    do {
+      responseJSONObject = try JSONSerialization.jsonObject(with: data)
+    } catch {
+      throw FunctionsError(.dataLoss, userInfo: [NSUnderlyingErrorKey: error])
     }
-  #else
-    @available(macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0, *)
-    private func callableStreamResult(fromResponseData data: Data,
-                                      endpointURL url: URL) throws -> JSONStreamResponse {
-      let data = try processedData(fromResponseData: data, endpointURL: url)
-
-      let responseJSONObject: Any
-      do {
-        responseJSONObject = try JSONSerialization.jsonObject(with: data)
-      } catch {
-        throw FunctionsError(.dataLoss, userInfo: [NSUnderlyingErrorKey: error])
-      }
 
-      guard let responseJSON = responseJSONObject as? [String: Any] else {
-        let userInfo = [NSLocalizedDescriptionKey: "Response was not a dictionary."]
-        throw FunctionsError(.dataLoss, userInfo: userInfo)
-      }
+    guard let responseJSON = responseJSONObject as? [String: Any] else {
+      let userInfo = [NSLocalizedDescriptionKey: "Response was not a dictionary."]
+      throw FunctionsError(.dataLoss, userInfo: userInfo)
+    }
 
-      if let _ = responseJSON["result"] {
-        return .result(responseJSON)
-      } else if let _ = responseJSON["message"] {
-        return .message(responseJSON)
-      } else {
-        throw FunctionsError(
-          .dataLoss,
-          userInfo: [NSLocalizedDescriptionKey: "Response is missing result or message field."]
-        )
-      }
+    if let _ = responseJSON["result"] {
+      return .result(responseJSON)
+    } else if let _ = responseJSON["message"] {
+      return .message(responseJSON)
+    } else {
+      throw FunctionsError(
+        .dataLoss,
+        userInfo: [NSLocalizedDescriptionKey: "Response is missing result or message field."]
+      )
     }
-  #endif // compiler(>=6.0)
+  }
 
   private func jsonData(jsonText: String) throws -> Data {
     guard let data = jsonText.data(using: .utf8) else {

FirebaseRemoteConfig/Tests/Swift/FakeUtils/MockURLProtocol.swift

@@ -15,17 +15,10 @@
 import Foundation
 
 class MockURLProtocol: URLProtocol {
-  #if compiler(>=6)
-    nonisolated(unsafe) static var requestHandler: ((URLRequest) throws -> (
-      Data,
-      HTTPURLResponse
-    ))?
-  #else
-    static var requestHandler: ((URLRequest) throws -> (
-      Data,
-      HTTPURLResponse
-    ))?
-  #endif
+  nonisolated(unsafe) static var requestHandler: ((URLRequest) throws -> (
+    Data,
+    HTTPURLResponse
+  ))?
 
   override class func canInit(with request: URLRequest) -> Bool {
     #if os(watchOS)

FirebaseSessions/Sources/Public/SessionsDependencies.swift

@@ -46,16 +46,10 @@ private final class AtomicBox<T> {
 /// dependent SDKs
 @objc(FIRSessionsDependencies)
 public class SessionsDependencies: NSObject {
-  #if compiler(>=6)
-    private nonisolated(unsafe) static let _dependencies: AtomicBox<Set<SessionsSubscriberName>> =
-      AtomicBox(
-        Set()
-      )
-  #else
-    private static let _dependencies: AtomicBox<Set<SessionsSubscriberName>> = AtomicBox(
+  private nonisolated(unsafe) static let _dependencies: AtomicBox<Set<SessionsSubscriberName>> =
+    AtomicBox(
       Set()
     )
-  #endif
 
   static var dependencies: Set<SessionsSubscriberName> {
     _dependencies.value()

FirebaseSharedSwift/Sources/third_party/FirebaseDataEncoder/FirebaseDataEncoder.swift

@@ -2611,19 +2611,11 @@ fileprivate struct _JSONKey : CodingKey {
 //===----------------------------------------------------------------------===//
 
 // NOTE: This value is implicitly lazy and _must_ be lazy. We're compiled against the latest SDK (w/ ISO8601DateFormatter), but linked against whichever Foundation the user has. ISO8601DateFormatter might not exist, so we better not hit this code path on an older OS.
-#if compiler(>=6)
 nonisolated(unsafe) fileprivate var _iso8601Formatter: ISO8601DateFormatter = {
   let formatter = ISO8601DateFormatter()
   formatter.formatOptions = .withInternetDateTime
   return formatter
 }()
-#else
-fileprivate var _iso8601Formatter: ISO8601DateFormatter = {
-  let formatter = ISO8601DateFormatter()
-  formatter.formatOptions = .withInternetDateTime
-  return formatter
-}()
-#endif
 
 //===----------------------------------------------------------------------===//
 // Error Utilities

FirebaseVertexAI/Sources/Chat.swift

@@ -27,11 +27,7 @@ public final class Chat: Sendable {
   }
 
   private let historyLock = NSLock()
-  #if compiler(>=6)
-    private nonisolated(unsafe) var _history: [ModelContent] = []
-  #else
-    private var _history: [ModelContent] = []
-  #endif
+  private nonisolated(unsafe) var _history: [ModelContent] = []
   /// The previous content from the chat that has been successfully sent and received from the
   /// model. This will be provided to the model for each message sent as context for the discussion.
   public var history: [ModelContent] {

FirebaseVertexAI/Sources/VertexAI.swift

@@ -140,21 +140,12 @@ public class VertexAI {
 
   let apiConfig: APIConfig
 
-  #if compiler(>=6)
-    /// A map of active  `VertexAI` instances keyed by the `FirebaseApp` name and the `location`, in
-    /// the format `appName:location`.
-    private nonisolated(unsafe) static var instances: [InstanceKey: VertexAI] = [:]
+  /// A map of active  `VertexAI` instances keyed by the `FirebaseApp` name and the `location`, in
+  /// the format `appName:location`.
+  private nonisolated(unsafe) static var instances: [InstanceKey: VertexAI] = [:]
 
-    /// Lock to manage access to the `instances` array to avoid race conditions.
-    private nonisolated(unsafe) static var instancesLock: os_unfair_lock = .init()
-  #else
-    /// A map of active  `VertexAI` instances keyed by the `FirebaseApp` name and the `location`, in
-    /// the format `appName:location`.
-    private static var instances: [InstanceKey: VertexAI] = [:]
-
-    /// Lock to manage access to the `instances` array to avoid race conditions.
-    private static var instancesLock: os_unfair_lock = .init()
-  #endif
+  /// Lock to manage access to the `instances` array to avoid race conditions.
+  private nonisolated(unsafe) static var instancesLock: os_unfair_lock = .init()
 
   let location: String?
 

FirebaseVertexAI/Tests/Unit/MockURLProtocol.swift

@@ -17,17 +17,10 @@ import XCTest
 
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 class MockURLProtocol: URLProtocol, @unchecked Sendable {
-  #if compiler(>=6)
-    nonisolated(unsafe) static var requestHandler: ((URLRequest) throws -> (
-      URLResponse,
-      AsyncLineSequence<URL.AsyncBytes>?
-    ))?
-  #else
-    static var requestHandler: ((URLRequest) throws -> (
-      URLResponse,
-      AsyncLineSequence<URL.AsyncBytes>?
-    ))?
-  #endif
+  nonisolated(unsafe) static var requestHandler: ((URLRequest) throws -> (
+    URLResponse,
+    AsyncLineSequence<URL.AsyncBytes>?
+  ))?
   override class func canInit(with request: URLRequest) -> Bool {
     #if os(watchOS)
       print("MockURLProtocol cannot be used on watchOS.")