FIX: work around random encoding errors

(symptom is that site is blank see: https://meta.discourse.org/t/actionview-template-error-incompatible-character-encodings-utf-8-and-ascii-8bit/19970)

lib/freedom_patches/safe_buffer.rb

@@ -0,0 +1,37 @@
+# For some reason safe buffer is getting invalid encoding in some cases
+# we work around the issue and log the problems
+#
+# The alternative is a broken website when this happens
+
+class ActiveSupport::SafeBuffer
+  def concat(value, raise_encoding_err=false)
+    if !html_safe? || value.html_safe?
+      super(value)
+    else
+      super(ERB::Util.h(value))
+    end
+  rescue Encoding::CompatibilityError
+    if raise_encoding_err
+      raise
+    else
+
+      unless encoding == Encoding::UTF_8
+        self.force_encoding("UTF-8")
+        unless valid_encoding?
+          encode!("utf-16","utf-8",:invalid => :replace)
+          encode!("utf-8","utf-16")
+        end
+        Rails.logger.warn("Encountered a non UTF-8 string in SafeBuffer - #{self}")
+      end
+
+      unless value.encoding == Encoding::UTF_8
+        value = value.dup.force_encoding("UTF-8").scrub
+        Rails.logger.warn("Attempted to concat a non UTF-8 string in SafeBuffer - #{value}")
+      end
+
+      concat(value,_raise=true)
+    end
+  end
+
+  alias << concat
+end

spec/components/freedom_patches/safe_buffer_spec.rb

@@ -0,0 +1,15 @@
+require 'spec_helper'
+require_dependency "freedom_patches/safe_buffer"
+
+describe ActiveSupport::SafeBuffer do
+  it "can cope with encoding weirdness" do
+    buffer = ActiveSupport::SafeBuffer.new
+    buffer << "\330".force_encoding("ASCII-8BIT")
+    buffer.force_encoding "ASCII-8BIT"
+    buffer << "hello\330\271"
+    buffer << "hello#{254.chr}".force_encoding("ASCII-8BIT").freeze
+
+    # we pay a cost for force encoding, the h gets dropped
+    buffer.should =~ /ello.*hello/
+  end
+end