RemoveDir task should log an error when failing

[KirillOsenkov]

I randomly saw this output:

C:\MSBuild\eng\BootStrapMSBuild.targets(28,5): error MSB3231: Unable to remove directory "C:\MSBuild\artifacts\bin\boot
strap\net472\MSBuild\". Access to the path 'Microsoft.CodeAnalysis.CSharp.dll' is denied. [C:\MSBuild\src\MSBuild.Boots
trap\MSBuild.Bootstrap.csproj]
C:\MSBuild\eng\BootStrapMSBuild.targets(28,5): error MSB4181: The "RemoveDir" task returned false but did not log an er
ror. [C:\MSBuild\src\MSBuild.Bootstrap\MSBuild.Bootstrap.csproj]

This means when RemoveDir can't remove a directory because of AccessDenied on a file within it, it fails but doesn't log an error.

[rainersigwald]

But . . . didn't it log that error? That's super confusing. I'm concerned it means we're throwing MSB4181 incorrectly. Let's try to figure out what's up soonish.

[KirillOsenkov]

I just tried this:

<Project DefaultTargets="Build">

  <Target Name="Build">
    <MakeDir Directories="1" />
    <Copy SourceFiles="C:\Users\kirill\.nuget\packages\sleep\1.0.0\tools\Sleep.exe" DestinationFolder="1" />
    <Exec Command="1\sleep.exe 1d" />
    <RemoveDir Directories="1" />
  </Target>

</Project>

If you run and then Ctrl+C to cancel the build you get this:

However if I manually run the .exe separately and then just build an empty project with RemoveDir, it works as expected:

So it might be what I saw is when I tried to cancel the build using Ctrl+C.

[KirillOsenkov]

AH! Needed to add ContinueOnError:

<Project DefaultTargets="Build">

  <Target Name="Build">
    <!--<MakeDir Directories="1" />
    <Copy SourceFiles="C:\Users\kirill\.nuget\packages\sleep\1.0.0\tools\Sleep.exe" DestinationFolder="1" />
    <Exec Command="1\sleep.exe 1d" />-->
    <RemoveDir Directories="1" ContinueOnError="true" />
  </Target>

</Project>

[KirillOsenkov]

It's not quite what I saw originally (it was an error, not a warning, somehow):

[KirillOsenkov]

This is the original snippet:

Oh, could it be that the project sets warnings as errors?

[KirillOsenkov]

Aha, OK, this is more like it:

<Project DefaultTargets="Build">

  <PropertyGroup>
    <MSBuildTreatWarningsAsErrors>true</MSBuildTreatWarningsAsErrors>
  </PropertyGroup>

  <Target Name="Build">
    <!--<MakeDir Directories="1" />
    <Copy SourceFiles="C:\Users\kirill\.nuget\packages\sleep\1.0.0\tools\Sleep.exe" DestinationFolder="1" />
    <Exec Command="1\sleep.exe 1d" />-->
    <RemoveDir Directories="1" ContinueOnError="true" />
  </Target>

</Project>

[Forgind]

I just hit this, too. I'd started a building MSBuild, cancelled it in the middle, and then built successfully. Then I built something else with its output and started building again and got that pair of errors.