'GeneratePathProperty' does not work on 'PackageDownload'

[sharwell]

The new <PackageDownload> elements do not support the GeneratePathProperty attribute, making it difficult to download a package whose contents will be used by an unrelated build task.

[nkolev92]

I'd be open to adding this eventually.
The thing is PackageDownload allows duplicate ids, so we'd need a different naming schema compared to PackageReference.

Note that because of the exactness of PackageDownload (specifically, only exact versions allowed), you can create the path fairly accurately as it will be:
$(NuGetPackageRoot)\$(PackageId)\$(PackageVersion)

[nkolev92]

@sandyarmstrong @KirillOsenkov

PackageDownload allows multiple versions, so we'd need a conflict resolution for that.

PkgDownloadCleanedUpPackageName_1 or something like that?

We'd also need to be different from PackageReference, so we'd need something to make them slightly different.

[sandyarmstrong]

How about GeneratePathProperty to get the directory path like in PackageReference, and GenerateNupkgPathProperty to get the nupkg, since it's a bit annoying to construct.

The resultant property names could just include the version. PkgSome_Id_1_0_0 for the directory, and PkgSome_Id_1_0_0_nupkg for the nupkg.

Am I missing anything that would make this problematic?

[KirillOsenkov]

One downside is when the version is changed you'd need to rename all properties.

We could have a heuristic that if only a single version is specified (the 90% case), the behavior should be identical to PackageReference (or maybe use a different prefix such as Package if it has to be separate from PackageReference convention).

I'd like to not have to mention the version in the common case.

[rainersigwald]

Prior art in CoreXT is that it defines multiple levels of the property:

    <PkgSystem_Memory_4_5_4_0>S:\NugetCache\System.Memory.4.5.4</PkgSystem_Memory_4_5_4_0>
    <PkgSystem_Memory_4_5_4>S:\NugetCache\System.Memory.4.5.4</PkgSystem_Memory_4_5_4>
    <PkgSystem_Memory_4_5>S:\NugetCache\System.Memory.4.5.4</PkgSystem_Memory_4_5>
    <PkgSystem_Memory_4>S:\NugetCache\System.Memory.4.5.4</PkgSystem_Memory_4>
    <PkgSystem_Memory>S:\NugetCache\System.Memory.4.5.4</PkgSystem_Memory>

Where I believe the highest version wins for each level. I don't know what it does for multiple prereleases in the same

Another option would be to punt to the user by taking metadata on the PackageDownload item

<PackageDownload Include="PackageName" Version="1.2.3" PathProperty="PackageName_Current" />
<PackageDownload Include="PackageName" Version="1.4.0-beta" PathProperty="PackageName_Experimental" />

[sandyarmstrong]

Another option would be to punt to the user by taking metadata on the PackageDownload item

<PackageDownload Include="PackageName" Version="1.2.3" PathProperty="PackageName_Current" />
<PackageDownload Include="PackageName" Version="1.4.0-beta" PathProperty="PackageName_Experimental" />

Yeah this is also a fine option.

[nkolev92]

Unfortunately the multiple includes with the same name version does not work quite like that.

Due to a CPS limitation, PackageDownload is only 1 item with ; separated version.

You'd need to specify the property with ; as well.

I think there's also value to keeping the functionality similar, keeping GeneratePathProperty.

[olegd-superoffice]

@nkolev92 If multiple versions are specified in PackageDownload using ; to separate versions, maybe property generated with GeneratePathProperty could include multiple paths using ; to separate paths in the same order?.

[KirillOsenkov]

This is still painful. My expectation is that the simplest case works as I expect it:

<PackageDownload Include="ILRepack.Lib.MSBuild.Task" Version="[2.0.18.1]" GeneratePathProperty="true" />