Fix the SingleThreadedPool's handling of disconnected connections

This shows that while 100% code coverage may not fix all bugs, it
certainly helps find some.

lib/sequel_core/connection_pool.rb

@@ -213,6 +213,7 @@ class Sequel::SingleThreadedPool
   #   to RuntimeError exceptions (default true)
   def initialize(opts={}, &block)
     @connection_proc = block
+    @disconnection_proc = opts[:disconnection_proc]
     @conns = {}
     @convert_exceptions = opts.include?(:pool_convert_exceptions) ? opts[:pool_convert_exceptions] : true
   end
@@ -226,13 +227,12 @@ def conn(server=:default)
   # This method simulates the ConnectionPool#hold API.
   def hold(server=:default)
     begin
-      yield(c = (@conns[server] ||= @connection_proc.call(server)))
-    rescue Sequel::DatabaseDisconnectError
       begin
+        yield(c = (@conns[server] ||= @connection_proc.call(server)))
+      rescue Sequel::DatabaseDisconnectError => dde
         @conns.delete(server)
         @disconnection_proc.call(c) if @disconnection_proc
-      rescue Exception => e
-        raise(@convert_exceptions && !e.is_a?(StandardError) ? RuntimeError.new(e.message) : e)
+        raise
       end
     rescue Exception => e
       # if the error is not a StandardError it is converted into RuntimeError.

spec/sequel_core/connection_pool_spec.rb

@@ -448,7 +448,8 @@ def value
 
 context "A single threaded pool with multiple servers" do
   setup do
-    @pool = Sequel::SingleThreadedPool.new(CONNECTION_POOL_DEFAULTS.merge(:servers=>{:read_only=>{}})){|server| server}
+    @max_size=2
+    @pool = Sequel::SingleThreadedPool.new(CONNECTION_POOL_DEFAULTS.merge(:disconnection_proc=>proc{|c| @max_size=3}, :servers=>{:read_only=>{}})){|server| server}
   end
 
   specify "should use the :default server by default" do
@@ -487,4 +488,25 @@ def value
     @pool.conn.should == nil
     @pool.conn(:read_only).should == nil
   end
+
+  specify ":disconnection_proc option should set the disconnection proc to use" do
+    @max_size.should == 2
+    proc{@pool.hold{raise Sequel::DatabaseDisconnectError}}.should raise_error(Sequel::DatabaseDisconnectError)
+    @max_size.should == 3
+  end
+
+  specify "#disconnection_proc= should set the disconnection proc to use" do
+    a = 1
+    @pool.disconnection_proc = proc{|c| a += 1}
+    proc{@pool.hold{raise Sequel::DatabaseDisconnectError}}.should raise_error(Sequel::DatabaseDisconnectError)
+    a.should == 2
+  end
+
+  specify "#hold should remove the connection if a DatabaseDisconnectError is raised" do
+    @pool.instance_variable_get(:@conns).length.should == 0
+    @pool.hold{}
+    @pool.instance_variable_get(:@conns).length.should == 1
+    proc{@pool.hold{raise Sequel::DatabaseDisconnectError}}.should raise_error(Sequel::DatabaseDisconnectError)
+    @pool.instance_variable_get(:@conns).length.should == 0
+  end
 end