fix: Replace connection.select_value with connection.query_value (#131)

Author: brunodccarvalho

lib/with_advisory_lock/mysql_advisory.rb

@@ -65,7 +65,7 @@ def supports_database_timeout?
     private
 
     def execute_successful?(mysql_function)
-      select_value("SELECT #{mysql_function}") == 1
+      query_value("SELECT #{mysql_function}") == 1
     end
   end
 end

lib/with_advisory_lock/postgresql_advisory.rb

@@ -71,7 +71,7 @@ def advisory_lock_exists_for?(lock_name, shared: false)
         LIMIT 1
       SQL
 
-      select_value(query).present?
+      query_value(query).present?
     rescue ActiveRecord::StatementInvalid
       # If pg_locks is not accessible, fall back to nil to indicate we should use the default method
       nil
@@ -96,7 +96,7 @@ def advisory_unlock_function(shared)
     end
 
     def execute_advisory(function, lock_keys, lock_name)
-      result = select_value(prepare_sql(function, lock_keys, lock_name))
+      result = query_value(prepare_sql(function, lock_keys, lock_name))
       LOCK_RESULT_VALUES.include?(result)
     end
 

test/with_advisory_lock/lock_test.rb

@@ -133,6 +133,25 @@ module LockTestCases
       # After the block, current_advisory_lock should be nil regardless
       assert_nil model_class.current_advisory_lock
     end
+
+    test 'does not write and read lock queries from the query cache' do
+      model_class.connection.cache do
+        model_class.with_advisory_lock!("lock", timeout_seconds: 0) {}
+        assert_nil model_class.connection.query_cache["SELECT GET_LOCK('lock', 0)"]
+
+        # Blocker thread uses a different connection
+        blocker = Thread.new do
+          model_class.with_advisory_lock("lock", timeout_seconds: 0) { sleep 1 }
+        end
+        # blocker should get the lock and not release it in time
+        sleep 0.5
+        lock_result = model_class.with_advisory_lock_result("lock", timeout_seconds: 0) do
+          raise "Successfully entered critical region while lock was held by other thread"
+        end
+        blocker.join
+        assert_not(lock_result.lock_was_acquired?)
+      end
+    end
   end
 end
 
@@ -177,7 +196,7 @@ def setup
     # Hold a lock in another connection - need to use the same prefixed name as the gem
     other_conn = model_class.connection_pool.checkout
     lock_keys = other_conn.lock_keys_for(lock_name)
-    other_conn.select_value("SELECT GET_LOCK(#{other_conn.quote(lock_keys.first)}, 0)")
+    other_conn.query_value("SELECT GET_LOCK(#{other_conn.quote(lock_keys.first)}, 0)")
 
     begin
       # Attempt to acquire with a short timeout - should fail quickly
@@ -190,7 +209,7 @@ def setup
       assert_not result
       assert elapsed < 3.0, "Expected quick timeout, but took #{elapsed} seconds"
     ensure
-      other_conn.select_value("SELECT RELEASE_LOCK(#{other_conn.quote(lock_keys.first)})")
+      other_conn.query_value("SELECT RELEASE_LOCK(#{other_conn.quote(lock_keys.first)})")
       model_class.connection_pool.checkin(other_conn)
     end
   end

test/with_advisory_lock/mysql_release_lock_test.rb

@@ -69,7 +69,7 @@ def setup
 
     # Acquire lock using SQL (ActiveRecord doesn't provide get_advisory_lock method)
     lock_keys = model_class.connection.lock_keys_for(lock_name)
-    result = model_class.connection.select_value("SELECT GET_LOCK(#{model_class.connection.quote(lock_keys.first)}, 0)")
+    result = model_class.connection.query_value("SELECT GET_LOCK(#{model_class.connection.quote(lock_keys.first)}, 0)")
     assert_equal 1, result, 'Failed to acquire lock using SQL'
 
     # Release using ActiveRecord signature (positional argument, as Rails does)
@@ -78,11 +78,11 @@ def setup
 
     # Verify lock is released
     lock_keys = model_class.connection.lock_keys_for(lock_name)
-    result = model_class.connection.select_value("SELECT GET_LOCK(#{model_class.connection.quote(lock_keys.first)}, 0)")
+    result = model_class.connection.query_value("SELECT GET_LOCK(#{model_class.connection.quote(lock_keys.first)}, 0)")
     assert_equal 1, result, 'Lock was not properly released'
 
     # Clean up
-    model_class.connection.select_value("SELECT RELEASE_LOCK(#{model_class.connection.quote(lock_keys.first)})")
+    model_class.connection.query_value("SELECT RELEASE_LOCK(#{model_class.connection.quote(lock_keys.first)})")
   end
 
   test 'release_advisory_lock handles connection errors gracefully' do
@@ -116,4 +116,3 @@ def setup
     end
   end
 end
-

test/with_advisory_lock/transaction_test.rb

@@ -7,8 +7,8 @@ class PostgreSQLTransactionScopingTest < GemTestCase
 
   setup do
     @pg_lock_count = lambda do
-      backend_pid = Tag.connection.select_value('SELECT pg_backend_pid()')
-      Tag.connection.select_value("SELECT COUNT(*) FROM pg_locks WHERE locktype = 'advisory' AND pid = #{backend_pid};").to_i
+      backend_pid = Tag.connection.query_value('SELECT pg_backend_pid()')
+      Tag.connection.query_value("SELECT COUNT(*) FROM pg_locks WHERE locktype = 'advisory' AND pid = #{backend_pid};").to_i
     end
   end