Use NuGet.Configuration to get the path to the NuGet global…

[Numpsy]

… packages folder

refs
#3853
#4209

I don't know the history of things in this area, I just hit #3853 when building some things that use paket on a system that has the globalPackagesFolder setting set to a custom location (on a different drive than the default user profile directory) and wondered if it would be possible to fix it by using the 'where is the cache folder' functionality in NuGet.Configuration rather than doing it locally (it contains the logic to look for NUGET_PACKAGES, then globalPackagesFolder, then the regular defaults)

[baronfel]

Definitely highly in favor of using NuGet'a apis to interface with parts of the system that they directly control. Love to see more of this.

[smoothdeveloper]

Giving a look at https://github.com/fsprojects/Paket/issues?q=NUGET_PACKAGES and places in the repository that mentions this environment variable maybe a small safety measure, to know how bad changing things would break.

I get the feeling NUGET_PACKAGES not being used anymore will break people, and maybe some CI users.

But conceptually, using another folder than the one nuget client uses, seems counter-natural, in today's environment.

Could we add an entry in release notes, IIUC, that mentions that this environment variable is not used anymore and that it will leverage the ambient nuget environment instead?

[Numpsy]

Nuget.Configuration reads NUGET_PACKAGES itself - https://github.com/NuGet/NuGet.Client/blob/d525b0e670f3b6cbd5c73a35f04730a9f658c852/src/NuGet.Core/NuGet.Configuration/Utility/SettingsUtility.cs#L231 - it uses that if set and then tries globalPackagesFolder if it isn't

[Numpsy]

This works for me when doing local builds of FAKE anyway -

• With a plain restore, it puts the packages in the cache path configured for my user
• If I set NUGET_PACKAGES to a custom path before doing a restore, the packages get put in that folder

[Numpsy]

This gets referenced from

Paket/integrationtests/Paket.IntegrationTests/NugetDownloadSpecs.fs

Line 24 in eed370a

let _ = directPaketInPathExWithEnv "restore" (scenarioTempPath "extracted-package-permissions") [Paket.Constants.GlobalPackagesFolderEnvironmentKey, localNugetDir]

so I suppose removing that would be a breaking change