Implementation notes:
* The hash implementation was not considering key value, causing "diffs
did not match" errors when a value was updated. Switching to default
HashResource implementation fixes this
* Using HashResource as a default exposed a bug in helper/schema that
needed to be fixed so the Set function is picked up properly during
Read
* Stop writing back values into the `key` attribute; it triggers extra
diffs when `default` is used. Computed values all just go into `var`.
* Includes a state migration to prevent unnecessary diffs based on
"key" attribute hashcodes changing.
In the tests:
* Switch from leaning on the public demo Consul instance to requiring a
CONSUL_HTTP_ADDR variable be set pointing to a `consul agent -dev`
instance to be used only for testing.
* Add a test that exposes the updating issues and covers the fixes
Fixes#774Fixes#1866Fixes#3023
Before all providers were using the helper.Schema approach the helper
function had these names. Now they all use names consistent with the Go
naming conventions except for these last few…
Paul Hinze