Prevent Index#delete with empty string.

Add a safe guard to not call ES client delete with an empty string.
Bug introduced with toptal#735

CHANGELOG.md

@@ -1,6 +1,7 @@
 # master
 
   * [#739](https://github.com/toptal/chewy/pull/739): Remove explicit `main` branch dependencies on rspec* gems after `rspec-mocks` 3.10.2 is released ([@rabotyaga][])
+  * [#740](https://github.com/toptal/chewy/pull/740): Prevent calling Index#delete with an empty string. ([@bhacaz][])
 
 # Version 5.2.0 (2021-01-28)
 

lib/chewy/index/actions.rb

@@ -79,8 +79,9 @@ def delete(suffix = nil)
           #   "The index parameter in the delete index API no longer accepts alias names.
           #   Instead, it accepts only index names (or wildcards which will expand to matching indices)."
           #   https://www.elastic.co/guide/en/elasticsearch/reference/6.8/breaking-changes-6.0.html#_delete_index_api_resolves_indices_expressions_only_against_indices
-          index_names = client.indices.get_alias(index: index_name(suffix: suffix)).keys
-          result = client.indices.delete index: index_names.join(',')
+          index_name_to_delete = index_name(suffix: suffix)
+          index_names = client.indices.get_alias(index: index_name_to_delete).join(',').presence || index_name_to_delete
+          result = client.indices.delete index: index_names
           Chewy.wait_for_status if result
           result
           # es-ruby >= 1.0.10 handles Elasticsearch::Transport::Transport::Errors::NotFound

spec/chewy/index/actions_spec.rb

@@ -97,6 +97,7 @@
       context do
         before { DummiesIndex.delete }
         specify { expect(Chewy.client.indices.exists(index: 'dummies')).to eq(false) }
+        specify { expect(DummiesIndex.delete).to eq(false) }
       end
     end