Until recently the NuGet Gallery used NuGet.Core for handling the nupkg. However a change was made in the Gallery code to use the .NET 4.5 Zip support in tandem with some of the functionality in NuGet.Core. The introduction of the newer Zip code in the Gallery was a good change allowing more optimized and secure code to be written; NuGet.Core does not depend on 4.5.
However, the Gallery code now diverges from the code in the NuGet.Core package. We would like to go back to a more consistent and unified implementation as far as is possible. (The split implementation actually introduced a bug in the Gallery: unifying implementation helps to avoid such things.)
The suggesting has been made that we could introduce a minor refactoring of parts of NuGet.Core to facilitate the introduction of a second, and 4.5 dependent, "extensions" assembly in the package.
However, the Gallery code now diverges from the code in the NuGet.Core package. We would like to go back to a more consistent and unified implementation as far as is possible. (The split implementation actually introduced a bug in the Gallery: unifying implementation helps to avoid such things.)
The suggesting has been made that we could introduce a minor refactoring of parts of NuGet.Core to facilitate the introduction of a second, and 4.5 dependent, "extensions" assembly in the package.