swift build: Even changing options which do not affect the build artifacts triggers a rebuild

[puni073]

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

Changing options which do not affect the build artifacts, such as -v, -j and -no-color-diagnostics triggers a rebuild.

Expected behavior

Changing options which do not affect the build artifacts does not trigger a rebuild.

Actual behavior

Changing options which do not affect the build artifacts triggers a rebuild.

Steps to reproduce

swift package init --name Main --type executable
swift build
swift build -v
swift build -j 1
swift build > build.log (This implies removing -color-diagnostics option)

Swift Package Manager version/commit hash

Swift Package Manager - Swift 6.0.3

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

swift --version

Swift version 6.0.3 (swift-6.0.3-RELEASE)
Target: x86_64-unknown-linux-gnu

cat /etc/lsb-release

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=24.04
DISTRIB_CODENAME=noble
DISTRIB_DESCRIPTION="Ubuntu 24.04.1 LTS"