add info: empty strings are interned

diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index e8e09820429b97366f926b28661df9d67a6e5c08..474aed55f7df83e2edc11075f917d72ecab73498 100644 (file)
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -8,6 +8,7 @@ UPGRADE NOTES - PHP X.Y
   c. POST data handling
   d. Arginfo changes
   e. tsrm_virtual_cwd.h moved to zend_virtual_cwd.h
+  f. empty strings are interned
 
 2. Build system changes
   a. Unix build system changes
@@ -115,6 +116,13 @@ UPGRADE NOTES - PHP X.Y
 
   Memory allocation is now managed by emalloc/efree instead of malloc/free.
 
+  f. empty strings are interned
+
+  String created using STR_EMPTY_ALLOC() are now interned.
+  convert_to_string use STR_EMPTY_ALLOC() for zval when IS_NULL.
+  STR_FREE() shoud be prefered as efree on such strings can raise memory corruption.
+
+
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 2. Build system changes
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