CI merge cache, QB/AR no escape

patch_commit_52e32c475952.patch

diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index f0fe96c35622a77066952d6a23fc526044590df7..d912540b5e2cd825b705088bee2497ba72fd04aa 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -2561,14 +2561,30 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 		{
 			$qb_variable	= 'qb_'.$val;
 			$qb_cache_var	= 'qb_cache_'.$val;
-			$qb_new 	= $this->$qb_cache_var;
-
-			foreach ($this->$qb_variable as &$qb_var)
+ 
+			// prep arrays with cached values
+			$qb_new    = $this->$qb_cache_var;
+			$qb_escape = $this->qb_cache_no_escape;
+ 
+			foreach ($this->$qb_variable as $i => &$qb_var)
 			{
-			 	in_array($qb_var, $qb_new, TRUE) OR $qb_new[] = $qb_var;
+			 	if ( ! in_array($qb_var, $qb_new, TRUE))
+			 	{
+					$qb_new[]    = $qb_var;
+					if ($val == 'select') $qb_escape[] = $this->qb_no_escape[$i];
+			 	}
+			 	else
+			 	{
+			 		// if ($val == 'select')
+			 		// {
+ 					//   i don't feel like doing an expensive 
+ 					//   foreach lookup, just to override escape?
+			 		// }
+			 	}
 			}
 
 			$this->$qb_variable = $qb_new;
+			if ($val == 'select') $this->qb_no_escape = $qb_escape;
 		}
 
 		// If we are "protecting identifiers" we need to examine the "from"
@@ -2577,10 +2593,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 		{
 			$this->_track_aliases($this->qb_from);
 		}
-
-		$this->qb_no_escape = array_merge($this->qb_no_escape, array_diff($this->qb_cache_no_escape, $this->qb_no_escape));
 	}
-
 	// --------------------------------------------------------------------
 
 	/**

Is the else condition necessary?

nope, the else part "could" be used to loop thru previously stored select variables and change the escape setting.