LIR: merge hash attributes of same name to support legacy configurations

logstash-core/lib/logstash/compiler/lscl.rb

@@ -101,9 +101,21 @@ def expr_attributes
  else
  [k,v]
  end
- }.reduce({}) do |hash,kv|
- k,v = kv
- hash[k] = v
+ }.reduce({}) do |hash, kv|
+ k, v = kv
+ existing = hash[k]
+ if existing.nil?
+ hash[k] = v
+ elsif existing.kind_of?(::Hash)
+ # For legacy reasons, a config can contain multiple `AST::Attribute`s with the same name
+ # and a hash-type value (e.g., "match" in the grok filter), which are merged into a single
+ # hash value; e.g., `{"match" => {"baz" => "bar"}, "match" => {"foo" => "bulb"}}` is
+ # interpreted as `{"match" => {"baz" => "bar", "foo" => "blub"}}`.
+ # (NOTE: this bypasses `AST::Hash`'s ability to detect duplicate keys)
+ hash[k] = existing.merge(v)
+ else
+ hash[k] = existing + v
+ end
  hash
  end
 

logstash-core/spec/logstash/compiler/compiler_spec.rb

@@ -193,6 +193,35 @@ def j
  expect(c_plugin).to ir_eql(j.iPlugin(INPUT, "generator", expected_plugin_args))
  end
  end
+
+ describe "a filter plugin that repeats a Hash directive" do
+ let(:source) { "input { } filter { #{plugin_source} } output { } " }
+ subject(:c_plugin) { compiled[:filter] }
+
+ let(:plugin_source) do
+ %q[
+ grok {
+ match => { "message" => "%{WORD:word}" }
+ match => { "examplefield" => "%{NUMBER:num}" }
+ break_on_match => false
+ }
+ ]
+ end
+
+ let(:expected_plugin_args) do
+ {
+ "match" => {
+ "message" => "%{WORD:word}",
+ "examplefield" => "%{NUMBER:num}"
+ },
+ "break_on_match" => "false"
+ }
+ end
+
+ it "should merge the contents of the individual directives" do
+ expect(c_plugin).to ir_eql(j.iPlugin(FILTER, "grok", expected_plugin_args))
+ end
+ end
  end
 
  context "inputs" do