Don't try to lock reads when using any SQLite adapter, it's redundant

and may generate an invalid query.

2 files changed, 17 insertions, 3 deletions

diff --git a/lib/arel/engines/sql/relations/relation.rb b/lib/arel/engines/sql/relations/relation.rb
index 8b71aa8c04..12b328151f 100644
--- a/lib/arel/engines/sql/relations/relation.rb
+++ b/lib/arel/engines/sql/relations/relation.rb
@@ -35,7 +35,7 @@ module Arel
           ("ORDER BY  #{order_clauses.join(', ')}"       unless orders.blank?      ),
           ("LIMIT     #{taken}"                          unless taken.blank?       ),
           ("OFFSET    #{skipped}"                        unless skipped.blank?     ),
-          ("#{locked}"                                   unless locked.blank?     )
+          ("#{locked}"                                   unless engine.adapter_name =~ /SQLite/ || locked.blank?)
       end
     end
 
diff --git a/spec/arel/engines/sql/unit/relations/lock_spec.rb b/spec/arel/engines/sql/unit/relations/lock_spec.rb
index 27239eb1a8..23f8a9f577 100644
--- a/spec/arel/engines/sql/unit/relations/lock_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/lock_spec.rb
@@ -17,12 +17,19 @@ module Arel
           })
         end
 
-        adapter_is_not :mysql do
+        adapter_is :postgresql do
           sql.should be_like(%Q{
             SELECT "users"."id", "users"."name"
             FROM "users" FOR UPDATE
           })
         end
+
+        adapter_is :sqlite3 do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+          })
+        end
       end
 
       it "manufactures a select query locking with a given lock" do
@@ -35,12 +42,19 @@ module Arel
           })
         end
 
-        adapter_is_not :mysql do
+        adapter_is :postgresql do
           sql.should be_like(%Q{
             SELECT "users"."id", "users"."name"
             FROM "users" LOCK IN SHARE MODE
           })
         end
+
+        adapter_is :sqlite3 do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+          })
+        end
       end
     end
   end