added a test to cover distinction between boolean return value of unserialize function and deserializing serialized boolean

Author: ahamid

ext/standard/tests/serialize/serialization_error_002.phpt

@@ -0,0 +1,52 @@
+--TEST--
+Test unserialize(): error is indistinguishable from deserialized boolean
+--FILE--
+<?php
+/* Prototype  : proto string serialize(mixed variable)
+ * Description: Returns a string representation of variable (which can later be unserialized) 
+ * Source code: ext/standard/var.c
+ * Alias to functions: 
+ */
+/* Prototype  : proto mixed unserialize(string variable_representation)
+ * Description: Takes a string representation of variable and recreates it 
+ * Source code: ext/standard/var.c
+ * Alias to functions: 
+ */
+
+echo "*** Testing unserialize() error/boolean distinction ***\n";
+
+$garbage = "obvious non-serialized data";
+$serialized_false = serialize(false);
+
+var_dump($serialized_false);
+
+$deserialized_garbage = unserialize($garbage);
+var_dump($deserialized_garbage);
+
+$deserialized_false = unserialize($serialized_false);
+var_dump($deserialized_false);
+
+echo "unserialize error and deserialized false are identical? " . (bool) ($deserialized_false == $deserialized_garbage) . "\n";
+
+// candidate safe idiom for determining whether data is serialized
+function isSerialized($str) {
+    return ($str == serialize(false) || @unserialize($str) !== false);
+}
+
+// Test unserialize error idiom
+var_dump(isSerialized($garbage));
+var_dump(isSerialized($serialized_false));
+
+echo "Done";
+?>
+--EXPECTF--
+*** Testing unserialize() error/boolean distinction ***
+string(4) "b:0;"
+
+Notice: unserialize(): Error at offset 0 of 27 bytes in %s/serialization_error_002.php on line 20
+bool(false)
+bool(false)
+unserialize error and deserialized false are identical? 1
+bool(false)
+bool(true)
+Done