Get latest runtime patch information without requiring users to update the SDK

[dsplaisted]

This designs PR covers some of the scenario: dotnet/designs#87

We now expect to solve this with some of the optional workload features: https://github.com/dotnet/designs/blob/master/accepted/2020/workloads/workloads.md

Plan of record (for now):

• Put the latest runtime versions in a workload manifest
• "Automatic" process downloads latest manifests into user-writeable space. These are the advertised manifests
• Use workload advertised manifest to notify that latest self-contained versions are out of date
• Have command to update latest self-contained versions
  • In later versions when we have acquisition, this would probably just be a workload update
  • In .NET 5, this would be a non-workload command which would copy the latest versions from the advertised manifest into a separate user-space file
• Runtime pack version selection would work as follows
  • Get latest version between currently installed manifest and user-space latest version file
  • Use this version for build
  • Also compare the version used for build with the latest version from the advertised manifest. If the used version is out of date, generate warning / message saying there's a newer version

[wli3]

The actual work needs to be done

1. add extra action of download advertised manifest in front of dotnet restore
2. warn user to update
3. verb design
4. implement the verb, download the manifest and store it in user location
5. SDK resolver look up and bind to global location
6. SDK resolver look up and bind to runtime implicit version manifest to local folder and pick the highest

overlap with 5.0 work: 5
overlap with future work: 1, 2, 3, 4, maybe 6

1 and 4 can reuse global tools infra(download a package and place it in a folder). 2 and 6 should be easy when there is 5. So, the only hard thing would only be 3. Now we need to balance designing 3 in advance + 1 and 4 as throw away work with SDK team continue to maintain shipping implicit version for another year.

[udlose]

@dsplaisted @marcpopMSFT Hi guys. Any update on this? Just making sure it didn't fall off the radar :)

[dsplaisted]

We have discussed various ways of solving this over the years but don't currently have concrete plans to do so. Right now we're working on making it easier to install and update the .NET SDK, which should help with this a bit from a different angle.

[udlose]

We have discussed various ways of solving this over the years but don't currently have concrete plans to do so. Right now we're working on making it easier to install and update the .NET SDK, which should help with this a bit from a different angle.

Thanks so much for such a quick reply! looking forward to see what you guys have coming.