Make Microsoft.Windows/Registry idiomatic

[michaeltlombardi]

Summary of the new feature / enhancement

As a user, I want the Microsoft.Windows/Registry resource to behave idiomatically, returning a representation of the current state that matches the instance schema.

The resource currently returns the following JSON representations from registry config get:

• For a key that exists:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "keyPath": "HKCU\\example"
  }

• For a key that doesn't exist:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "keyPath": ""
  }

• For a value that exists:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "keyPath": "HKCU\\example\\subkey",
    "valueName": "NewKeyAndValue",
    "valueData": {
      "String": "No errors"
    }
  }

• For a value that doesn't exist, registry config get errors with exit code 3:

  Error getting config: The registry key or value name does not exist.: Failed to query registry value

Proposed technical implementation details (optional)

The idiomatic representation of the resource instance should always include the keyPath, even when the key doesn't exist. The instance should use the value of the _ensure property to indicate whether the instance is present or absent.

The idiomatic representations for an instance are:

• For a key that exists:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "_ensure": "Present",
    "keyPath": "HKCU\\example"
  }

• For a key that doesn't exist:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "_ensure": "Absent",
    "keyPath": "HKCU\\example"
  }

• For a value that exists:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "_ensure": "Present",
    "keyPath": "HKCU\\example\\subkey",
    "valueName": "NewKeyAndValue",
    "valueData": {
      "String": "No errors"
    }
  }

• For a value that doesn't exist:

  {
    "$id": "https://developer.microsoft.com/json-schemas/windows/registry/20230303/Microsoft.Windows.Registry.schema.json",
    "_ensure": "Absent",
    "keyPath": "HKCU\\example\\subkey",
    "valueName": "NewKeyAndValue"
  }

This would enable users and integrating tools to reason about the state of the instance without having to know that an empty string for keyPath indicates that the key doesn't exist.