Plugin doesn't work with Swift 6.0

[sebsto]

I am trying to launch swift build commands from a command plugin. Until Swift 6.0, it worked. Now, the .build directory is locked and I receive

  Another instance of SwiftPM is already running using '/Users/stormacq/Documents/amazon/code/swift/lambda/swift-aws-lambda-sam-dsl/Examples/SAM/.build', waiting until that process has finished execution...

So, I tried --scratch-path .build.2 . The lock problem is gone, but I receive weird network (DNS) errors, such as

file:///Applications/Xcode-16.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift build --scratch-path .build.2 -c release --product AWSLambdaDeploymentDescriptor
  warning: /Users/stormacq/Library/org.swift.swiftpm/configuration is not accessible or not writable, disabling user-level cache features.
  warning: /Users/stormacq/Library/org.swift.swiftpm/security is not accessible or not writable, disabling user-level cache features.
  warning: /Users/stormacq/Library/Caches/org.swift.swiftpm is not accessible or not writable, disabling user-level cache features.
  Fetching https://github.com/swift-server/swift-aws-lambda-events.git
  error: Failed to clone repository https://github.com/swift-server/swift-aws-lambda-events.git:
    Cloning into bare repository '/Users/stormacq/swift-aws-lambda-sam-dsl/Examples/SAM/.build.2/repositories/swift-aws-lambda-events-00ed9a01'...
    fatal: unable to access 'https://github.com/swift-server/swift-aws-lambda-events.git/': Could not resolve host: github.com
error: file:///Applications/Xcode-16.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift build --scratch-path .build.2 -c release --product AWSLambdaDeploymentDescriptor failed with code 1

The network errors only happen when swift build commands are launched through the SwiftPM command plugin. When I type swift build --scratch-path .build.2 manually in a terminal, all packages are fetched correctly.