Swift Testing should create the attachments-path if it does not exist

[bkhouri]

Description

The following is emitted when running swift test --attachments-path /path/does/not/exists, where the provided path does not exists

Invalid value "/path/does/not/exists" for argument ---attachments-path

Reproduction

1. Install Swift Toolchain
2. Run the following

cd /tmp
swift package init --package-path funky --type library --enable-swift-testing
swift test --package-path funky  --attachments-path ./foo/bar/baz

Expected behavior

The tests are executed without any failures. However, the following occurs

❯ swift test --package-path funky  --attachments-path ./foo/bar/baz
Building for debugging...
warning: MACOSX_DEPLOYMENT_TARGET The macOS deployment target 'MACOSX_DEPLOYMENT_TARGET' is set to 10.13, but the range of supported deployment target versions is 12.0 to 27.0.99.
warning: MACOSX_DEPLOYMENT_TARGET The macOS deployment target 'MACOSX_DEPLOYMENT_TARGET' is set to 10.13, but the range of supported deployment target versions is 12.0 to 27.0.99.
[99/100] funkyTests-product 156 / 157
[100/100] 
Build complete! (18.17 secs.)
Test Suite 'All tests' started at 2026-04-07 14:15:58.207.
Test Suite 'All tests' passed at 2026-04-07 14:15:58.208.
         Executed 0 tests, with 0 failures (0 unexpected) in 0.000 (0.001) seconds
Invalid value "./foo/bar/baz" for argument ---attachments-path

Environment

Using macOS OSS Swift main-snapshot from April 1, 2026

❯ swiftly use -p                                                   
/Users/bkhouri/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2026-04-01-a.xctoolchain

❯ swift --version                                                  
Apple Swift version 6.4-dev (LLVM b8889af02f47cf7, Swift cf7481b28905381)
Target: arm64-apple-macosx26.0
Build config: +assertions

❯ uname -a       
Darwin BKs-Work-MBP-M4-Pro.local 25.5.0 Darwin Kernel Version 25.5.0: Fri Mar 20 19:24:15 PDT 2026; root:xnu_development-12377.120.72.0.4~12/DEVELOPMENT_ARM64_T6041 arm64

Additional information

No response

[grynspan]

I'm open to changing this behaviour, but it is by design. I don't think it would require a Swift Evolution proposal per se, but we should discuss it at an upcoming TWG meeting before taking any action. (Feel free to join us!)