Fixing issue where a beforeDelete() could trigger a table truncation.

Moving the exists check below beforeDelete() and behavior->beforeDelete() so any records deleted in the callbacks will not exist when db->delete() is called.  Test updated. Fixes #250

cake/libs/model/model.php

@@ -1746,11 +1746,16 @@ function del($id = null, $cascade = true) {
 		}
 		$id = $this->id;
 
-		if ($this->exists() && $this->beforeDelete($cascade)) {
-			$db =& ConnectionManager::getDataSource($this->useDbConfig);
-			if (!$this->Behaviors->trigger($this, 'beforeDelete', array($cascade), array('break' => true, 'breakOn' => false))) {
+
+		if ($this->beforeDelete($cascade)) {
+			$filters = $this->Behaviors->trigger($this, 'beforeDelete', array($cascade), array(
+				'break' => true, 'breakOn' => false
+			));
+			if (!$filters || !$this->exists()) {
 				return false;
 			}
+			$db =& ConnectionManager::getDataSource($this->useDbConfig);
+
 			$this->_deleteDependent($id, $cascade);
 			$this->_deleteLinks($id);
 			$this->id = $id;

cake/tests/cases/libs/model/model_delete.test.php

@@ -664,14 +664,18 @@ function testBeforeDeleteWipingTable() {
 		$this->assertTrue($result > 1, 'Comments are all gone.');
 	}
 
-	function testBeforeDeleteWipingTable2() {
+/**
+ * test that deleting the same record from the beforeDelete and the delete doesn't truncate the table.
+ *
+ * @return void
+ */
+	function testBeforeDeleteWipingTableWithDuplicateDelete() {
 		$this->loadFixtures('Comment');
 
 		$Comment =& new BeforeDeleteComment();
 		$Comment->delete(1);
 
 		$result = $Comment->find('count');
-
 		$this->assertTrue($result > 1, 'Comments are all gone.');
 	}
 }