Fix MakeRelative regression intrdouced in msbuild shipped with VS16.10

[pmisik]

Fixes #6493

Context

Changes Made

Testing

Added missing directory related unittests

Notes

[rainersigwald]

Can you rebase this off the vs16.10 branch so we can (potentially, not promising yet) take it for a patch release of 16.10?

[dnfadmin]

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[dnfadmin]

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[pmisik]

Can you rebase this off the vs16.10 branch so we can (potentially, not promising yet) take it for a patch release of 16.10?

I'll do it if after it pass CI.
First step was to break unittests (as directory related unittests were missing) to prove it has broken previous MSBuild.
Second commit is fix based on @dsparkplug analysis.
I hope it will fix it.
Unfortunately I cannot run it locally on my machine as I see
Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(141,5): error NETSDK1045: The current .NET SDK does not support targeting .NET 6.0. Either target .NET 5.0 or lower, or use a version of the .NET SDK that supports .NET 6.0.

[rainersigwald]

Unfortunately I cannot run it locally on my machine as I see
Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(141,5): error NETSDK1045: The current .NET SDK does not support targeting .NET 6.0. Either target .NET 5.0 or lower, or use a version of the .NET SDK that supports .NET 6.0.

To fix that, either rebase (to get back to a branch that targets .NET 5.0), or install the latest .NET 6.0 preview SDK. I recommend the former :)

[dsparkplug]

While this patch will fix the issue with directories, a directory separator will be added to the end of the output for all input, causing the existing unit tests for files to fail. A solution would need to check whether path is a file.

[dsparkplug]

Added a new pull request to replace this one #6508

[pmisik]

Can you rebase this off the vs16.10 branch so we can (potentially, not promising yet) take it for a patch release of 16.10?

I've rebased and squashed (to me intermediate commit are useless - single commits on production branches are better to find cause of issue) work to be potentially applied on 16.10 branch.
I vote for fix in VS16.10.
For company I work at this is blocker bug (we have many supported target branches with different vc toolsets).
Unfortunately, there is no support in VS2019 to have multiple msbuild versions side by side for various VC toolsets (the same issue applies on WDK - as it overwrites original one build sub-directory :-( ).
So, if any developer at company install VS 16.10 it will break all existing branches development for him.

Should it be as new feature request for VS2022 to have support side by side msbuild suppport?

After squash I amended commit message to be explicitly visible all credits to this fix belongs to @dsparkplug
Author and committer should belongs to @dsparkplug.
Mine only intentions is to be fixed this issue ASAP in production.

[rainersigwald]

I vote for fix in VS16.10.
For company I work at this is blocker bug (we have many supported target branches with different vc toolsets).
Unfortunately, there is no support in VS2019 to have multiple msbuild versions side by side for various VC toolsets (the same issue applies on WDK - as it overwrites original one build sub-directory :-( ).
So, if any developer at company install VS 16.10 it will break all existing branches development for him.

Thanks for this--this kind of detailed problem description helps us get approval for servicing bugs. We'll let you know the outcome of that process (I'm optimistic).

[Forgind]

#6513 had the key change from this PR, so closing as superseded by that. Thanks for the contribution @pmisik!