Retain the original message in a Message object

We only format and convert it after passing it through the formatter.
That way, we can ensure that the actually interesting formatted value
is valid.

lib/rackstash/formatter.rb

@@ -28,7 +28,7 @@ module Rackstash
 
   class RawFormatter
     def call(_severity, _timestamp, _progname, msg)
-      msg
+      msg.is_a?(String) ? msg : msg.inspect
     end
   end
 end

lib/rackstash/message.rb

@@ -34,7 +34,7 @@ module Rackstash
       progname: PROGNAME,
       formatter: RAW_FORMATTER
     )
-      @message = cleanup_message(msg)
+      @message = dup_freeze(msg)
 
       @severity = Integer(severity)
       @severity = 0 if @severity < 0
@@ -54,7 +54,7 @@ module Rackstash
     end
 
     def to_s
-      @formatter.call(severity_label, @time, @progname, @message)
+      cleanup @formatter.call(severity_label, @time, @progname, @message)
     end
     alias_method :to_str, :to_s
     alias_method :as_json, :to_s
@@ -66,8 +66,7 @@ module Rackstash
     #
     # @param msg [#to_s] a message to be added to the buffer
     # @return [String] the sanitized frozen message
-    def cleanup_message(msg)
-      msg = msg.inspect unless msg.is_a?(String)
+    def cleanup(msg)
       msg = utf8_encode(msg)
       # remove useless ANSI color codes
       msg.gsub!(/\e\[[0-9;]*m/, EMPTY_STRING)

spec/rackstash/formatter_spec.rb

@@ -54,4 +54,12 @@ describe Rackstash::RawFormatter do
     msg = 'my message'
     expect(formatter.call('ERROR', Time.now, 'progname', msg)).to equal msg
   end
+
+  it 'inspects non-string messages' do
+    obj = Object.new
+
+    expect(obj).to receive(:inspect).and_return('object')
+    expect(formatter.call('ERROR', Time.now, 'progname', obj)).to eql 'object'
+  end
+
 end

spec/rackstash/message_spec.rb

@@ -11,44 +11,20 @@ require 'rackstash/message'
 describe Rackstash::Message do
   describe '#message' do
     it 'dups the message string' do
-      str = 'a message'
+      str = 'a message'.encode(Encoding::ASCII_8BIT)
       message = Rackstash::Message.new(str)
 
       expect(message.message).to eql str
       expect(message.message).not_to equal str
+      expect(message.message.encoding).to eql Encoding::ASCII_8BIT
       expect(message.message).to be_frozen
     end
 
-    it 'cleans the message' do
-      messages = [
-        ["First\r\nSecond",         "First\nSecond"],
-        ["First\r\nSecond\n\r",     "First\nSecond\n\n"],
-        ["Foo\r\n\rBar",            "Foo\n\nBar"],
-        ["\r \tWord\n\nPhrase\n",   "\n \tWord\n\nPhrase\n"],
-        ["\e[31mRED TEXT\e[0m",     'RED TEXT']
-      ]
+    it 'accepts non-string objects' do
+      exception = StandardError.new('An error')
+      message = Rackstash::Message.new(exception)
 
-      messages.each do |msg, clean|
-        message = Rackstash::Message.new(msg)
-        expect(message.message).to eql clean
-      end
-    end
-
-    it 'encodes the message as UTF-8' do
-      utf8_str = 'Dönerstraße'
-      latin_str = utf8_str.encode(Encoding::ISO8859_9)
-      expect(latin_str.encoding).to eql Encoding::ISO8859_9
-
-      message = Rackstash::Message.new(latin_str)
-      expect(message.message).to eql utf8_str
-      expect(message.message.encoding).to eql Encoding::UTF_8
-    end
-
-    it 'does not raise an error on incompatible encodings' do
-      binary = Digest::SHA256.digest('string')
-      message = Rackstash::Message.new(binary)
-
-      expect(message.message).to include '<27>'
+      expect(message.message).to eq exception
     end
   end
 
@@ -127,7 +103,7 @@ describe Rackstash::Message do
       expect(Rackstash::Message.new('').formatter).to equal Rackstash::Message::RAW_FORMATTER
 
       message = Rackstash::Message.new('Beep boop')
-      expect(message.to_s).to equal message.message
+      expect(message.to_s).to eql 'Beep boop'
     end
   end
 
@@ -153,6 +129,47 @@ describe Rackstash::Message do
 
       expect(message.to_s).to eql 'Formatted Message'
     end
+
+    it 'cleans the message' do
+      messages = [
+        ["First\r\nSecond",         "First\nSecond"],
+        ["First\r\nSecond\n\r",     "First\nSecond\n\n"],
+        ["Foo\r\n\rBar",            "Foo\n\nBar"],
+        ["\r \tWord\n\nPhrase\n",   "\n \tWord\n\nPhrase\n"],
+        ["\e[31mRED TEXT\e[0m",     'RED TEXT']
+      ]
+
+      messages.each do |msg, clean|
+        message = Rackstash::Message.new(msg)
+        expect(message.to_s).to eql clean
+      end
+    end
+
+    it 'encodes the message as UTF-8' do
+      utf8_str = 'Dönerstraße'
+      latin_str = utf8_str.encode(Encoding::ISO8859_9)
+      expect(latin_str.encoding).to eql Encoding::ISO8859_9
+
+      message = Rackstash::Message.new(latin_str)
+      expect(message.to_s).to eql utf8_str
+      expect(message.to_s.encoding).to eql Encoding::UTF_8
+    end
+
+    it 'does not raise an error on incompatible encodings' do
+      binary = Digest::SHA256.digest('string')
+      message = Rackstash::Message.new(binary)
+
+      expect(message.to_s).to include '<27>'
+      expect(message.to_s.encoding).to eql Encoding::UTF_8
+    end
+
+    it 'accepts non-string objects' do
+      exception = StandardError.new('An error')
+      message = Rackstash::Message.new(exception)
+
+      expect(message.to_s).to eql '#<StandardError: An error>'
+    end
+
   end
 
   describe '#frozen?' do