xml: Drop unused XML_GetCurrentByteCount() compatibility wrapper (#20476)

Author: ndossche

UPGRADING.INTERNALS

@@ -60,6 +60,8 @@ PHP 8.6 INTERNALS UPGRADE NOTES
 - ext/xml:
   . Removed the XML_ExpatVersion() libxml compatibility wrapper,
     as it was unused.
+  . Removed the XML_GetCurrentByteCount() libxml compatibility wrapper,
+    as it was unused and could return the wrong result.
 
 ========================
 4. OpCode changes

ext/xml/compat.c

@@ -644,14 +644,6 @@ XML_GetCurrentByteIndex(XML_Parser parser)
 			(parser->parser->input->cur - parser->parser->input->base);
 }
 
-PHP_XML_API int
-XML_GetCurrentByteCount(XML_Parser parser)
-{
-	/* TODO: this is identical to ByteIndex; it should probably
-	 * be different */
-	return (int) XML_GetCurrentByteIndex(parser);
-}
-
 PHP_XML_API void
 XML_ParserFree(XML_Parser parser)
 {

ext/xml/expat_compat.h

@@ -147,7 +147,6 @@ PHP_XML_API const XML_Char *XML_ErrorString(int);
 PHP_XML_API int  XML_GetCurrentLineNumber(XML_Parser);
 PHP_XML_API int  XML_GetCurrentColumnNumber(XML_Parser);
 PHP_XML_API long XML_GetCurrentByteIndex(XML_Parser);
-PHP_XML_API int  XML_GetCurrentByteCount(XML_Parser);
 PHP_XML_API void XML_ParserFree(XML_Parser);
 
 #elif defined(HAVE_LIBEXPAT)