NoCache option does not work for packages.config based restore/install (GlobalPackagesFolder)

[zarenner]

TODO:
We should probably cover it here in one go - Updated the top comment

• NoCache should download the package, and store it in the cache
• NoCaching should download the pacakge but not write it into the cache - Debate the name and the flags before making the change

The NoCache option doesn't work with packages.config based restore or install. The packages are still downloaded to the global package folder, and then copied to the PackagesDirectory.

Also, is %localappdata%\NuGet\Cache used anymore? GetPackageSources still adds it as a source if NoCache isn't specified, but I don't see where anything is ever written to it.

Perhaps this is a gap in my understanding... are %localappdata%\NuGet\Cache ("MachineCache") and %userprofile%.nuget\packages ("GlobalPackagesFolder") meant to do different things? I don't understand why they both exist.

[yishaigalatzer]

Global packages folder and the cache folders are two different things.

1. %localappdata%\NuGet\Cache Is a cache - Means you can get packages from there instead of downloading them again. It is off in NuGet3, and we might want to bring it back, we didn't make that determination yet.
2. %userprofile%.nuget\packages is an install target (or restore target depending who you ask), this is where packages are expanded to, so they get consumed by the projects.

We should revisit this inconsistent state of things and fix it.

My current thoughts are to

1. Bring back the machine cache either in the %localappdata%\NuGet\Cache or expand the packages to the global path and use that as a cache.
2. Respect --no-cache for all scenarios

[zarenner]

"expand the packages to the global path and use that as a cache."

Maybe I'm still misunderstanding something - this is the behavior I see. Packages are downloaded to the global path, unpacked there, then copied to [PackagesDirectory]. Restoring the package again into a new directory doesn't re-download the file, it pulls it from the global packages directory. To prove this point - if you add a file into an expanded package in the global packages folder, that file gets copied over if you do a restore into a new PackagesDirectory.

See https://github.com/NuGet/NuGet3/blob/dev/src/NuGet.Protocol.Core.v3/DownloadResourceV3.cs and https://github.com/NuGet/NuGet3/blob/dev/src/NuGet.Protocol.Core.v3/Utility/GlobalPackagesFolderUtility.cs, and https://github.com/NuGet/NuGet3/blob/dev/src/NuGet.Packaging/PackageFolderReader.cs which is used to copy over the expanded package.

Can you please explain what you mean by "this is where packages are expanded to, so they get consumed by the projects"?

[yishaigalatzer]

It is not a cache, it is used as another package source

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Subject: Re: [Home] NoCache option does not work for packages.config based restore/install (GlobalPackagesFolder) (#1406)

"expand the packages to the global path and use that as a cache."

Maybe I'm still misunderstanding something - this is the behavior I see. Packages are downloaded to the global path, unpacked there, then copied to [PackagesDirectory]. Restoring the package again into a new directory doesn't re-download the file, it pulls it from the global packages directory. To prove this point - if you add a file into an expanded package in the global packages folder, that file gets copied over if you do a restore into a new PackagesDirectory.

See https://github.com/NuGet/NuGet3/blob/dev/src/NuGet.Protocol.Core.v3/DownloadResourceV3.cshttps://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fgithub.com%2fNuGet%2fNuGet3%2fblob%2fdev%2fsrc%2fNuGet.Protocol.Core.v3%2fDownloadResourceV3.cs&data=01%7c01%7cyigalatz%40microsoft.com%7c2843560296bc4e458cf008d2c071b175%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=G6KD%2bGTW3%2bVSK90gZzGa%2fnBxZActBlsb%2fpIxWf6u6rk%3d and https://github.com/NuGet/NuGet3/blob/dev/src/NuGet.Protocol.Core.v3/Utility/GlobalPackagesFolderUtility.cshttps://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fgithub.com%2fNuGet%2fNuGet3%2fblob%2fdev%2fsrc%2fNuGet.Protocol.Core.v3%2fUtility%2fGlobalPackagesFolderUtility.cs&data=01%7c01%7cyigalatz%40microsoft.com%7c2843560296bc4e458cf008d2c071b175%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=5flXov4naEvMsaNSzthYRr2gNjj6Fix9IEcRyaWb8lw%3d, and https://github.com/NuGet/NuGet3/blob/dev/src/NuGet.Packaging/PackageFolderReader.cshttps://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fgithub.com%2fNuGet%2fNuGet3%2fblob%2fdev%2fsrc%2fNuGet.Packaging%2fPackageFolderReader.cs&data=01%7c01%7cyigalatz%40microsoft.com%7c2843560296bc4e458cf008d2c071b175%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=1qc5BGs9k3SMRS0q3BOORGaOYobELzu5KxN2nOtZr4A%3d which is used to copy over the expanded package.

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[yishaigalatzer]

The -NoCache option is a misnomer, it means always download the packages (but they will still make it into the cache).

Looking at our current backlog, this seems relatively low priority.

[zjrunner]

For clarity, are you tracking this workitem to mean -NoCache should download the package each time, but it will not impact expansion into the GlobalPackagesDirectory (profile.nuget) -- that will continue to happen even with -NoCache? Trying to decide if I need to open another workitem to avoid always expanding into GlobalPackagesDirectory or if it is addressed here.

[yishaigalatzer]

We should probably cover it here in one go - Updated the top comment

• NoCache should download the package, and store it in the cache
• NoCaching should download the pacakge but not write it into the cache - Debate the name and the flags before making the change

[yishaigalatzer]

@emgarten please orchestrate a design review for this ask, so we can end up with a clear behavior document, and tests etc.