MSVC does not support long paths inside Docker container

[jdoubleu]

Describe the bug
Apparently MSVC does not support long paths inside a Docker container. On the host, it works perfectly fine.

To Reproduce
I've prepared a minimal repo: https://github.com/jdoubleu/msvc-docker-bug
Steps to reproduce the behavior:

1. clone the above repo
2. run docker build -t msvc-docker-bug .

The Dockerfile should be self-explanatory.

Expected behavior
The second compilation from the Dockerfile should work just as fine as the first one.

The behavior should match the host environment, where MSVC does not have any issues working with long paths. Even when long path support has not been enabled system-wide.

Configuration:

• Edition: Windows 11 Pro (10.0.22631 Build 22631)
• Base Image being used: mcr.microsoft.com/windows/servercore:ltsc2022
• Container engine: docker
• Container Engine version: Docker version 27.5.1, build 9f9e405

Additional information:
Related issue: #361

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[xlazom00]

Is it woking on normal windows? As I don't think so. MSVC and msbuild has problem with long path and I also reported this issues on MS

[jdoubleu]

Yes, it perfectly works fine on a normal Windows host. I've set the registry key at HKLM\SYSTEM\CurrentControlSet\Control\FileSystem in both cases.