Distinguish ConnectionNotEstablished messages: no conn pool for the class, or no conn available from the pool

1 files changed, 4 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 759e162e19..fd185de589 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -538,7 +538,10 @@ module ActiveRecord
       # for (not necessarily the current class).
       def retrieve_connection(klass) #:nodoc:
         pool = retrieve_connection_pool(klass)
-        (pool && pool.connection) or raise ConnectionNotEstablished
+        raise ConnectionNotEstablished, "No connection pool for #{klass}" unless pool
+        conn = pool.connection
+        raise ConnectionNotEstablished, "No connection for #{klass} in connection pool" unless conn
+        conn
       end
 
       # Returns true if a connection that's accessible to this class has