[Xcode 27] flutter/packages "Swift format" repo check fails (swift-format moves @preconcurrency @testable import) #194268

"Swift format" in Mac_arm64 macos_repo_checks fails when the bots run Xcode 27.

https://ci.chromium.org/b/8668494649107525137 (staging.shadow run of the Xcode 27 CI experiment, flutter/packages#13158, sdk_version: 27a266a)

The step runs xcrun swift-format -i over every Swift file and then diffs. With the swift-format bundled in Xcode 27, exactly one file comes out different:

diff --git a/packages/video_player/video_player_avfoundation/darwin/RunnerTests/VideoPlayerTests.swift b/packages/video_player/video_player_avfoundation/darwin/RunnerTests/VideoPlayerTests.swift
@@ -4,9 +4,10 @@
 import AVFoundation
 import Testing
-@preconcurrency @testable import video_player_avfoundation
 import video_player_avfoundation_objc

+@preconcurrency @testable import video_player_avfoundation
+
 #if os(iOS)
   import Flutter
 #else

The new formatter moves the attributed import (@preconcurrency @testable import …) out of the sorted import block into its own group. The current Xcode 26.2 (17c52) formatter leaves it in place, so the file is correctly formatted today and will stop being correctly formatted the moment the bots move to Xcode 27.

Options:

• reorder that one import in VideoPlayerTests.swift so both formatter versions accept it (needs checking that Xcode 26.2's swift-format doesn't move it back), or
• land the reformat together with the Xcode 27 roll.

Related: #194019 (the other Xcode 27 failures in the same experiment runs).