Correct Map keys must be unique warnings in definitions YAML

[dougbu]

When developers have definitions/shared/linux.yaml open in VS Code and perhaps other editors, they'll observe numerous Map keys must be unique errors. These errors don't impact our builds or commands like .\osob-cli.cmd definitions b/c parsers from YamlDotNet ignore the problem and chooses the last value (if the values are different). However the errors make it more difficult to find real problems in the YAML.

One issue is with definitions such as

- <<: *Windows11Client
  <<: *ServicingSubscription
  Name: windows.11.amd64.client.svc
  Public: false

The << pseudo-key appears twice. Our current version of YamlDotNet doesn't handle e.g., <<: [ *Windows11Client, *ServicingSubscription ] when the merged maps contain lots of references. I haven't tested enough to confirm whether the issue is the depth of references to some of our anchors, the overall complication of our YAML, or something else.

likely fix would be to upgrade to a more recent YamlDotNet version. We're at v6.0.0 (published 2019-03-15) though v13.7.1 has been out for 3 months (at the time of this writing). Interesting fixes for YAML deserialization include:

• Throw an exception on duplicate keys aaubry/YamlDotNet#750
  • resolves Deserializing is not handling non-unique keys correctly aaubry/YamlDotNet#536
  • this does not change the default behaviour, meaning we should be able to upgrade w/o removing all duplicate keys
  • we should chain in DeserializerBuilder.WithDuplicateKeyChecking() when instantiating the builder to take advantage of this new feature
• MergingParser deserializer can now handle nested NodeSequence + tests aaubry/YamlDotNet#780
  • resolves MergingParser cannot parse yaml with array alias that contains list aaubry/YamlDotNet#777
  • this fix will probably allow us to merge multiple maps in one reference (e.g., <<: [ *Windows11Client, *ServicingSubscription ] as mentioned above)
• Create a value promise right after seeing an anchor aaubry/YamlDotNet#598
  • resolves How to handle cyclic references aaubry/YamlDotNet#597
  • not an issue at the moment but should help to catch YAML authoring errors going forward
• Merge sequence of anchors in reverse order aaubry/YamlDotNet#596
  • resolves YamlDotNet merges anchor list in wrong order. aaubry/YamlDotNet#594
  • a deviation from the YAML spec that could cause problems in our current YAML if we somehow rely on the incorrect behaviour
• Disallow usage of alias before anchor declaration aaubry/YamlDotNet#491
  • this may cause errors b/c I believe we have a few anchors in our YAML defined after their first reference

Release Note Category

• Feature changes/additions
• Bug fixes
• Internal Infrastructure Improvements

Release Note Description

Upgraded to a new YamlDotNet version (v13.7.1).