Validate VMR Shipping Packages

[ellahathaway]

Closes dotnet/source-build#4068

When not all packages are signed, the validation stage is marked with a warning and an error message is outputted to the UI.

Note: Until dotnet/source-build#4678 is resolved, the validation stage will output the error that not all packages are signed. This is because mac & linux builds are currently doing dry-run signing.

[ellahathaway]

Test run (internal Microsoft link)

[mmitche]

Awesome!!!!

[mmitche]

Approved with minor tweak if necessary.

[ViktorHofer]

Will this break official builds until the linked issue is resolved? Or is the error just ignored?

[mmitche]

When not all packages are signed, the validation stage is marked with a warning and an error message is outputted to the UI.

The stage warns currently

[ViktorHofer]

This will make the official build longer again but I see that there isn't a great way to avoid that. Is the plan to add the "publish to bar and feeds" stage after this one and block on it being green or run it in parallel to this new stage? @mmitche

[mmitche]

This will make the official build longer again but I see that there isn't a great way to avoid that. Is the plan to add the "publish to bar and feeds" stage after this one and block on it being green or run it in parallel to this new stage? @mmitche

We could add in parallel. No reason to block publishing. I do not expect that we will keep this stage on in all cases. I expect that most builds will eventually be unsigned and this step will be skipped.