Apply code review suggestions: to use decorator as a proc call, doc syntax fix, unit test errors fix.

Author: mashhurs

docs/index.asciidoc

@@ -235,7 +235,6 @@ The next scheduled run:
 {es} Query Language (ES|QL) provides a SQL-like interface for querying your {es} data.
 
 To use {esql}, this plugin needs to be installed in {ls} 8.17.4 or newer, and must be connected to {es} 8.11 or newer.
-|===
 
 To configure {esql} query in the plugin, set the `response_type` to `esql` and provide your {esql} query in the `query` parameter.
 

lib/logstash/inputs/elasticsearch.rb

@@ -312,8 +312,8 @@ def register
     if @response_type == 'esql'
       validate_ls_version_for_esql_support!
       validate_esql_query!
-      ignored_options = original_params.keys & %w(index size slices search_api, docinfo, docinfo_target, docinfo_fields)
-      @logger.info("Configured #{ignored_options} params are ignored in ES|QL query") if ignored_options&.size > 1
+      not_allowed_options = original_params.keys & %w(index size slices search_api, docinfo, docinfo_target, docinfo_fields)
+      raise(LogStash::ConfigurationError, "Configured #{not_allowed_options} params are not allowed while using ES|QL query") if not_allowed_options&.size > 1
     else
       @base_query = LogStash::Json.load(@query)
       if @slices

lib/logstash/inputs/elasticsearch/esql.rb

@@ -17,7 +17,7 @@ class Esql
         # @param plugin [LogStash::Inputs::Elasticsearch] The parent plugin instance
         def initialize(client, plugin)
           @client = client
-          @plugin = plugin
+          @event_decorator = plugin.method(:decorate_event)
           @target_field = plugin.params["target"]
           @retries = plugin.params["retries"]
 
@@ -80,7 +80,7 @@ def process_response(columns, values, output_queue)
                 event.set(field_reference, ESQL_PARSERS_BY_TYPE[column.type].call(value))
               end
             end
-            @plugin.decorate_event(event)
+            @event_decorator.call(event)
             output_queue << event
           rescue => e
             # if event creation fails with whatever reason, inform user and tag with failure and return entry as it is

spec/inputs/elasticsearch_esql_spec.rb

@@ -6,7 +6,8 @@
 describe LogStash::Inputs::Elasticsearch::Esql do
   let(:client) { instance_double(Elasticsearch::Client) }
   let(:esql_client) { double("esql-client") }
-  let(:plugin) { instance_double(LogStash::Inputs::Elasticsearch, params: plugin_config) }
+
+  let(:plugin) { instance_double(LogStash::Inputs::Elasticsearch, params: plugin_config, decorate_event: nil) }
   let(:plugin_config) do
     {
       "query" => "FROM test-index | STATS count() BY field",
@@ -19,7 +20,6 @@
     it "sets up the ESQL client with correct parameters" do
       expect(esql_executor.instance_variable_get(:@query)).to eq(plugin_config["query"])
       expect(esql_executor.instance_variable_get(:@retries)).to eq(plugin_config["retries"])
-      expect(esql_executor.instance_variable_get(:@plugin)).to eq(plugin)
       expect(esql_executor.instance_variable_get(:@target_field)).to eq(nil)
     end
   end

spec/inputs/elasticsearch_spec.rb

@@ -1439,6 +1439,24 @@ def extract_transport(client) # on 7.x client.transport is a ES::Transport::Clie
         end
       end
 
+      context "ES|QL query and DSL params used together" do
+        let(:config) {
+          super().merge({
+            "index" => "my-index",
+            "size" => 1,
+            "slices" => 1,
+            "search_api" => "auto",
+            "docinfo" => true,
+            "docinfo_target" => "[@metadata][docinfo]",
+            "docinfo_fields" => ["_index"],
+          })}
+
+        it "raises a config error" do
+          mixed_fields = %w[index size slices docinfo_fields]
+          expect { plugin.register }.to raise_error(LogStash::ConfigurationError, /Configured #{mixed_fields} params are not allowed while using ES|QL query/)
+        end
+      end
+
       describe "ES|QL query"  do
         context "when query is valid" do
           it "does not raise an error" do