Swift 6.1 hangs on Ubuntu 24.04 when re-building project

[EsbenRud]

Description

When I re-build my project using swift 6.1 on Ubuntu 24.04 it hangs and produces no output.

Deleting .build folder and re-issuing the build command makes it work but the whole project with dependencies is then compiled.

Why does swift 6.1 hang when .build folder is existing?

I have tried other projects and the same situation (hang) happens every time I try.

Reproduction

This build command will hang when .build folder does exist:

$HOME/swift-6.1-RELEASE-ubuntu24.04/usr/bin/swift build -c release --package-path $HOME/Projects/SyncherApi

Expected behavior

I would expect the swift command to end when the modified files have been re-compiled.

Environment

Swift version 6.1 (swift-6.1-RELEASE)
Target: x86_64-unknown-linux-gnu

Additional information

No response