Fix exception when logging SQL w/ nil binary value.

activerecord/CHANGELOG.md

@@ -1,3 +1,15 @@
+*   Log nil binary column values correctly.
+
+    When an object with a binary column is updated with a nil value
+    in that column, the SQL logger would throw an exception when trying
+    to log that nil value. This only occurs when updating a record
+    that already has a non-nil value in that column since an initial nil
+    value isn't included in the SQL anyway (at least, when dirty checking
+    is enabled.) The column's new value will now be logged as `<NULL binary data>`
+    to parallel the existing `<N bytes of binary data>` for non-nil values.
+
+    *James Coleman*
+
 *   Stringify all variable keys of mysql connection configuration.
 
     When the `sql_mode` variable for mysql adapters is set in the configuration

activerecord/lib/active_record/log_subscriber.rb

@@ -25,7 +25,7 @@ module ActiveRecord
         if column.binary?
           # This specifically deals with the PG adapter that casts bytea columns into a Hash.
           value = value[:value] if value.is_a?(Hash)
-          value = "<#{value.bytesize} bytes of binary data>"
+          value = value.nil? ? "<NULL binary data>" : "<#{value.bytesize} bytes of binary data>"
         end
 
         [column.name, value]

activerecord/test/cases/log_subscriber_test.rb

@@ -125,5 +125,12 @@ class LogSubscriberTest < ActiveRecord::TestCase
       wait
       assert_match(/<16 bytes of binary data>/, @logger.logged(:debug).join)
     end
+
+    def test_nil_binary_data_is_logged
+      binary = Binary.create(data: "")
+      binary.update_attributes(data: nil)
+      wait
+      assert_match(/<NULL binary data>/, @logger.logged(:debug).join)
+    end
   end
 end