[Source compatibility suite] PennyBot failing to build with Swift 6 mode

[justice-adams-apple]

Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

PennyBot is failing to build to with swift 6 mode with the nightly main toolchain. The error seen in the log is:

bot/.build/checkouts/swift-collections/Sources/DequeModule/_DequeBuffer.swift:44:14: error: let '_emptyDequeStorage' is not concurrency-safe because non-'Sendable' type 'ManagedBuffer<_DequeBufferHeader, Void>' may have shared mutable state
42 | /// The type-punned empty singleton storage instance.
43 | @usableFromInline
44 | internal let _emptyDequeStorage = _DequeBuffer<Void>.create(
   |              |- error: let '_emptyDequeStorage' is not concurrency-safe because non-'Sendable' type 'ManagedBuffer<_DequeBufferHeader, Void>' may have shared mutable state
   |              |- note: add '@MainActor' to make let '_emptyDequeStorage' part of global actor 'MainActor'
   |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
45 |   minimumCapacity: 0,
46 |   makingHeaderWith: { _ in

https://ci.swift.org/job/swift-PR-source-compat-suite-test-macOS/321/artifact/swift-source-compat-suite/FAIL_penny-bot_6.0_BuildSwiftPackage.log

It looks like this is because swift-collections is not Swift 6 ready yet but I thought Swift PM would handle that?

I'm not sure if this is expected for swift-pm

Expected behavior

Expected the project to build correctly

Actual behavior

No response

Steps to reproduce

swift build --disable-sandbox --package-path penny-bot --verbose --configuration release --build-tests -Xswiftc -swift-version -Xswiftc 6 -Xswiftc -enable-testing

Swift Package Manager version/commit hash

2215d09

Swift & OS version (output of swift --version ; uname -a)

Apple Swift version 6.2-dev (LLVM 2bef1d1fbdd6b87, Swift 27386786a0cc850)
Target: x86_64-apple-macosx10.13

[justice-adams-apple]

cc @lorentey

[dschaefer2]

No, SwiftPM doesn't take the language mode into account when resolving packages.