Fix exception when logging SQL w/ nil binary value.

3 files changed, 20 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index df73eb4484..0b27aabf63 100644
--- a/activerecord/CHANGELOG.md
+++ b/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
diff --git a/activerecord/lib/active_record/log_subscriber.rb b/activerecord/lib/active_record/log_subscriber.rb
index 654ef21b07..17d0c52e47 100644
--- a/activerecord/lib/active_record/log_subscriber.rb
+++ b/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]
diff --git a/activerecord/test/cases/log_subscriber_test.rb b/activerecord/test/cases/log_subscriber_test.rb
index 97c0350911..a578e81844 100644
--- a/activerecord/test/cases/log_subscriber_test.rb
+++ b/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