ensure plugins are correctly compiled outside of same plugin section

Fixes #5459

logstash-core/lib/logstash/config/config_ast.rb

@@ -76,6 +76,14 @@ module LogStash; module Config; module AST
     @defered_conditionals_index = val
   end
 
+  def self.plugin_instance_index
+    @plugin_instance_index
+  end
+
+  def self.plugin_instance_index=(val)
+    @plugin_instance_index = val
+  end
+
   class Node < Treetop::Runtime::SyntaxNode
     def text_value_for_comments
       text_value.gsub(/[\r\n]/, " ")
@@ -86,6 +94,7 @@ module LogStash; module Config; module AST
     def compile
       LogStash::Config::AST.defered_conditionals = []
       LogStash::Config::AST.defered_conditionals_index = 0
+      LogStash::Config::AST.plugin_instance_index = 0
       code = []
 
       code << <<-CODE
@@ -140,7 +149,6 @@ module LogStash; module Config; module AST
     # like @filter_<name>_1
     def initialize(*args)
       super(*args)
-      @i = 0
     end
 
     # Generate ruby code to initialize all the plugins.
@@ -196,9 +204,9 @@ module LogStash; module Config; module AST
 
       plugins.each do |plugin|
         # Unique number for every plugin.
-        @i += 1
+        LogStash::Config::AST.plugin_instance_index += 1
         # store things as ivars, like @filter_grok_3
-        var = :"#{plugin.plugin_type}_#{plugin.plugin_name}_#{@i}"
+        var = :"#{plugin.plugin_type}_#{plugin.plugin_name}_#{LogStash::Config::AST.plugin_instance_index}"
         # puts("var=#{var.inspect}")
         @variables[plugin] = var
       end

logstash-core/spec/logstash/config/config_ast_spec.rb

@@ -144,6 +144,49 @@ describe LogStashConfigParser do
     end
   end
 
+  context "when using two plugin sections of the same type" do
+    let(:pipeline_klass) do
+      Class.new do
+        def initialize(config)
+          grammar = LogStashConfigParser.new
+          @config = grammar.parse(config)
+          @code = @config.compile
+          eval(@code)
+        end
+        def plugin(*args);end
+      end
+    end
+    context "(filters)" do
+      let(:config_string) {
+        "input { generator { } }
+         filter { filter1 { } }
+         filter { filter1 { } }
+         output { output1 { } }"
+      }
+
+
+      it "should create a pipeline with both sections" do
+        generated_objects = pipeline_klass.new(config_string).instance_variable_get("@generated_objects")
+        filters = generated_objects.keys.map(&:to_s).select {|obj_name| obj_name.match(/^filter.+?_\d+$/) }
+        expect(filters.size).to eq(2)
+      end
+    end
+
+    context "(filters)" do
+      let(:config_string) {
+        "input { generator { } }
+         output { output1 { } }
+         output { output1 { } }"
+      }
+
+
+      it "should create a pipeline with both sections" do
+        generated_objects = pipeline_klass.new(config_string).instance_variable_get("@generated_objects")
+        outputs = generated_objects.keys.map(&:to_s).select {|obj_name| obj_name.match(/^output.+?_\d+$/) }
+        expect(outputs.size).to eq(2)
+      end
+    end
+  end
   context "when creating two instances of the same configuration" do
 
     let(:config_string) {