Host build are "sandboxed" by target triple

[rauhul]

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

• [X] 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

When switching target triples from say arm64-apple-macosx15-macho to armv7em-apple-none-macho, SwiftPM rebuilds all host content. I think is because "tools/host" content is not shared between target triples. You can see this by looking in the .build directory and seeing that each target directory contains their own -tools directory built for the host.

See output of ➜ swift-mmio git:(main) ✗ fd '.*-tool' .build/aarch64-unknown-linux-gnu/debug .build/arm64-apple-macosx/debug | sort | pbcopy

files.txt

[dschaefer2]

Deleted earlier poorly thought out reply.

Why do you have output for linux?

[rauhul]

Why do you have output for linux?

was cross compiling for linux, but could've easily been an embedded triple instead

[dschaefer2]

Why do you have output for linux?

was cross compiling for linux, but could've easily been an embedded triple instead

Ah, it looked like another host build with docker or something. Makes sense.

Question is, why do target output directories have tools at all. They should only be on the host.

[dschaefer2]

Does your armv7em directory have -tools things? I wonder if it considers linux a host...

At any rate, definitely something not right.

[rauhul]

Hmm I can't reproduce this in a clean area. I'm gonna close it and reopen with a concrete repro if it does.

[dschaefer2]

Thanks!