From 4fe38848982abdb544bfb48603e9c24133039707 Mon Sep 17 00:00:00 2001
From: Cris Ward <cris@duodesign.co.uk>
Date: Thu, 27 Jul 2017 15:08:05 +0100
Subject: [PATCH] Release connection when query cannot be built

This was leaking connection when a query could not be build - ie if an invalid column name was used.
More info here - https://github.com/crystal-lang/crystal-mysql/issues/40
---
 src/db/pool_prepared_statement.cr | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/db/pool_prepared_statement.cr b/src/db/pool_prepared_statement.cr
index d50b240..23b049d 100644
--- a/src/db/pool_prepared_statement.cr
+++ b/src/db/pool_prepared_statement.cr
@@ -34,7 +34,12 @@ module DB
       clean_connections
       conn, existing = @db.checkout_some(@connections)
       @connections << WeakRef.new(conn) unless existing
-      conn.prepared.build(@query)
+      begin
+        conn.prepared.build(@query)
+      rescue ex
+        conn.release
+        raise ex
+      end
     end
 
     private def clean_connections