Can't build on exFAT-formatted drives (was Error Domain=NSCocoaErrorDomain Code=512 ... NSUnderlyingError=Win32Error(code: 87))

[Aero-Applications]

Description

Hello, and thank you for developing this language.

I found that I could not build new or existing swift projects located on a secondary drive (Specifically an HDD, my other SSD works fine) in Windows 10 (D:/path/to/project).

Please don't feel like you have to fix this right away, I simply wanted this to be out there so that others looking up error 512 could see what I have deduced from this error.

Reproduction

D:\Path\To\Project>swift package init
Creating library package: Project 
Creating Package.swift
Creating .gitignore
Creating Sources
Creating Sources\Project\Project .swift
Creating Tests/
Creating Tests\ProjectTests/
Creating Tests\ProjectTests\ProjectTests.swift

D:\Path\To\Project>swift build
Error Domain=NSCocoaErrorDomain Code=512 "(null)"UserInfo={NSURL=file:///D:/Path/To/Project/.build/x86_64-unknown-windows-msvc/debug/Project.build/output-file-map.json, NSUnderlyingError=Win32Error(code: 87), NSFilePath=D:/Path/To/Project\.build\x86_64-unknown-windows-msvc\debug\Project.build\output-file-map.json}

Expected behavior

D:\Path\To\Project>swift package init
Creating library package: Project 
Creating Package.swift
Creating .gitignore
Creating Sources
Creating Sources\Project\Project .swift
Creating Tests/
Creating Tests\ProjectTests/
Creating Tests\ProjectTests\Project Tests.swift

D:\Path\To\Project>swift build
Building for debugging...
[5/5] Compiling Project Project .swift
Build complete! (6.21s)

Environment

Windows 10:

D:\Path\To\Project>swift --version
Swift version 6.2.4 (swift-6.2.4-RELEASE)
Target: x86_64-unknown-windows-msvc
Build config: +assertions

Additional information

If this happens to you, please try a different hard drive.

I don't know exactly what's causing HDD to fail.

Hard Drive Specs:

• Type: LocalDisk (Not External)
• Format: exFat
• Free space: Sufficient

[tbkka]

Are your SSD all using NTFS? It's more likely to be an exFAT vs. NTFS issue rather than HDD vs SSD.

CC: @dschaefer2

[Aero-Applications]

Yes, thank you, the 2 SSDs are both formatted with NTFS.

[carlpeto]

The bit in the error NSFilePath=D:/Path/To/Project\.build\x86_64-unknown-windows-msvc\debug\Project.build\output-file-map.json looks a bit suspicious to me because it has mixed path separators, forward slashes and back slashes.

Is it possible to zip and upload the contents of the project it created, to see if swiftpm did something slightly odd like put forward slashes or mixed separators into some file in the created project?

(edit)
Or is this synthetic, you've replaced path by hand in the messages you posted? Either way, I feel like the created Package.swift, etc. might be useful just for a look?

[Aero-Applications]

Sadly, though I can upload a zip of the generated project for you, That may have been my fault... I wanted to change the path 'Dev/Swift' to 'Path/To/Project' to be more descriptive, since then I updated swift from 6.2 to 6.3 and now the error message is different:

'error: encountered an I/O error (code: 512) while reading D:\Path\To\Project\.build\x86_64-unknown-windows-msvc\debug\Project.build\output-file-map.json'.

As you can see, all separators are the same in this output (which is this time unmodified, I actually created the directories 'Path/To/Project' this time).

None the less here is a zip of the generated files:

Path.zip

Thanks for the help :)

[carlpeto]

Thank you. It's helpful for me just to look through everything for an obvious problem. I can't see anything wrong with the package you uploaded.

The error you're getting with Swift 6.3 looks fairly similar to the original problem I think. My guess is @tbkka is closest. (Something about having the package files on a drive mounted on an ExFAT partition is possibly causing issues during swiftpm running a build.)

I'll leave this for someone at swiftpm to look at as it's not my area!

Thanks very much for this issue, and in particular it's really helpful that you have isolated the fact that it seems to only occur on a drive formatted with ExFAT, which is possibly something that isn't quite as often used/tested.

[Aero-Applications]

No problem, Thanks for looking into it so quickly :). I hope this helps people who run into the two aforementioned error messages.