Luca Cavanna 21d52f0dab
Ensure that local cluster alias is never treated as remote (#37121)
With #36997 we added support for providing a local cluster alias with a
`SearchRequest`. We intended to make sure that when provided as part of
a search request, the cluster alias would never be used for connection
lookups. Yet due to a bug we would still end up looking up the
connection from the remote ones.

This commit adds a test to make sure that whenever we set the cluster
alias to the `SearchRequest` (which can only be done at transport), such
alias is used as index prefix in the returned hits. No errors are thrown
despite no remote clusters are configured indicating that such alias is
never used for connection look-ups.

Also, we add explicit support for the empty cluster alias when printing
 out index names through `RemoteClusterAware#buildRemoteIndexName`.
In fact we don't want to print out `:index` when the cluster alias is
set to empty string, but rather `index`. Yet, the semantic of empty
string is different compared to `null` as it will still disable final
reduction. This will be used in CCS when searching against remote
clusters as well as the local one, the local one will have empty prefix
yet it will need to disable final reduction so that its results will be
properly merged with the ones coming from the remote clusters.
2019-01-04 12:19:31 +01:00
..