Remove fingerprinting from AR session store; fix bug in store. Closes #2612

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2754 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 22 insertions, 29 deletions

diff --git a/actionpack/CHANGELOG b/actionpack/CHANGELOG
index 26503aef8e..b65916e85a 100644
--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
@@ -1,5 +1,9 @@
 *SVN*
 
+* Remove ARStore session fingerprinting.
+
+* Fix obscure bug in ARStore.
+
 * Added TextHelper#strip_tags for removing HTML tags from a string (using HTMLTokenizer) #2229 [marcin@junkheap.net]
 
 * Added a reader for flash.now, so it's possible to do stuff like flash.now[:alert] ||= 'New if not set' #2422 [Caio Chassot]
diff --git a/actionpack/lib/action_controller/session/active_record_store.rb b/actionpack/lib/action_controller/session/active_record_store.rb
index 90a84511be..c5f49fa8bc 100644
--- a/actionpack/lib/action_controller/session/active_record_store.rb
+++ b/actionpack/lib/action_controller/session/active_record_store.rb
@@ -50,10 +50,10 @@ class CGI
     class ActiveRecordStore
       # The default Active Record class.
       class Session < ActiveRecord::Base
+        before_update :loaded? # Don't try to save if we haven't loaded the session
         before_save   :marshal_data!
         before_save   :ensure_data_not_too_big
-        before_update :data_changed?
-
+        
         class << self
 
           # Don't try to reload ARStore::Session in dev mode.
@@ -73,7 +73,6 @@ class CGI
 
           def marshal(data)     Base64.encode64(Marshal.dump(data)) end
           def unmarshal(data)   Marshal.load(Base64.decode64(data)) end
-          def fingerprint(data) Digest::MD5.hexdigest(data)         end
 
           def create_table!
             connection.execute <<-end_sql
@@ -109,17 +108,14 @@ class CGI
             end
         end
 
-        # Lazy-unmarshal session state.  Take a fingerprint so we can detect
-        # whether to save changes later.
+        # Lazy-unmarshal session state.
         def data
           unless @data
-            case @data = read_attribute('data')
+            case data = read_attribute('data')
               when String
-                @fingerprint = self.class.fingerprint(@data)
-                @data = self.class.unmarshal(@data)
-              when nil
-                @data = {}
-                @fingerprint = nil
+                @data = self.class.unmarshal(data)
+              else
+                @data = data || {}
             end
           end
           @data
@@ -127,12 +123,12 @@ class CGI
 
         private
           def marshal_data!
-            write_attribute('data', self.class.marshal(@data || {}))
+            write_attribute('data', self.class.marshal(self.data))
           end
-
-          def data_changed?
-            old_fingerprint, @fingerprint = @fingerprint, self.class.fingerprint(read_attribute('data'))
-            old_fingerprint != @fingerprint
+          
+          # Has the session been loaded yet?
+          def loaded?
+            !! @data
           end
 
           # Ensures that the data about to be stored in the database is not
@@ -188,7 +184,6 @@ class CGI
 
           def marshal(data)     Base64.encode64(Marshal.dump(data)) end
           def unmarshal(data)   Marshal.load(Base64.decode64(data)) end
-          def fingerprint(data) Digest::MD5.hexdigest(data)         end
 
           def create_table!
             @@connection.execute <<-end_sql
@@ -220,16 +215,13 @@ class CGI
           @new_record
         end
 
-        # Lazy-unmarshal session state.  Take a fingerprint so we can detect
-        # whether to save changes later.
+        # Lazy-unmarshal session state.
         def data
           unless @data
             if @marshaled_data
-              @fingerprint = self.class.fingerprint(@marshaled_data)
               @data, @marshaled_data = self.class.unmarshal(@marshaled_data), nil
             else
               @data = {}
-              @fingerprint = nil
             end
           end
           @data
@@ -249,14 +241,11 @@ class CGI
                 #{@@connection.quote(marshaled_data)} )
             end_sql
           else
-            old_fingerprint, @fingerprint = @fingerprint, self.class.fingerprint(marshaled_data)
-            if old_fingerprint != @fingerprint
-              @@connection.update <<-end_sql, 'Update session'
-                UPDATE #{@@table_name}
-                SET #{@@connection.quote_column_name(@@data_column)}=#{@@connection.quote(marshaled_data)}
-                WHERE #{@@connection.quote_column_name(@@session_id_column)}=#{@@connection.quote(session_id)}
-              end_sql
-            end
+            @@connection.update <<-end_sql, 'Update session'
+              UPDATE #{@@table_name}
+              SET #{@@connection.quote_column_name(@@data_column)}=#{@@connection.quote(marshaled_data)}
+              WHERE #{@@connection.quote_column_name(@@session_id_column)}=#{@@connection.quote(session_id)}
+            end_sql
           end
         end