Why is UseSymboliclinksIfPossible disabled inside Visual Studio?

[giovanni-bozzano]

In my projects, I've set all the properties that enable symbolic links creation in the MSBuild Copy task. That is:

• CreateSymbolicLinksForCopyFilesToOutputDirectoryIfPossible
• CreateSymbolicLinksForCopyAdditionalFilesIfPossible
• CreateSymbolicLinksForCopyLocalIfPossible
• CreateSymbolicLinksForAdditionalFilesIfPossible
• CreateSymbolicLinksForPublishFilesIfPossible

For some reason, some of them are set to false when BuildingInsideVisualStudio is true:
https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.Common.CurrentVersion.targets#L4704
https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.Common.CurrentVersion.targets#L4721
https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.Common.CurrentVersion.targets#L4906
https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.Common.CurrentVersion.targets#L5974

The only comment above those lines does not explain the reason for this behavior and I wasn't able to retrieve any information about it.

Is there a specific reason why these properties are disabled in Visual Studio?

[rokonec]

Although it looks good on paper, symbolic links were causing too many hard-to-debug build and execution issues, so I guess VS team decided it does more harm than gain and make it opt-in.

Additionally, copy-on-write, which is supposed to be released to GA soon, will make "usage of symbolic link for copy performance" deprecated.

But, I was not behind that decision so please take my explanation with a grain of salt.