Add the new file (what a great idea!) and ignore a deprecation warning

Author: StanFromIreland

Modules/expat/hash_table.h

@@ -0,0 +1,78 @@
+/* Hash table related internal API
+                            __  __            _
+                         ___\ \/ /_ __   __ _| |_
+                        / _ \\  /| '_ \ / _` | __|
+                       |  __//  \| |_) | (_| | |_
+                        \___/_/\_\ .__/ \__,_|\__|
+                                 |_| XML parser
+
+   Copyright (c) 2026 Sebastian Pipping <sebastian@pipping.org>
+   Licensed under the MIT license:
+
+   Permission is  hereby granted,  free of charge,  to any  person obtaining
+   a  copy  of  this  software   and  associated  documentation  files  (the
+   "Software"),  to  deal in  the  Software  without restriction,  including
+   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
+   distribute, sublicense, and/or sell copies of the Software, and to permit
+   persons  to whom  the Software  is  furnished to  do so,  subject to  the
+   following conditions:
+
+   The above copyright  notice and this permission notice  shall be included
+   in all copies or substantial portions of the Software.
+
+   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
+   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
+   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+   USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+   SPDX-License-Identifier: MIT
+*/
+
+#if ! defined(HASH_TABLE_H)
+#  define HASH_TABLE_H 1
+
+#  include "expat.h"    // for XML_Bool, XML_Parser
+#  include "internal.h" // for XML_NONTESTING_STATIC
+
+#  include <stddef.h> // for size_t
+
+typedef const XML_Char *KEY;
+
+typedef struct {
+  KEY name;
+} NAMED;
+
+typedef struct {
+  NAMED **v;
+  unsigned char power;
+  size_t size;
+  size_t used;
+  XML_Parser parser;
+} HASH_TABLE;
+
+typedef struct {
+  NAMED **p;
+  NAMED **end;
+} HASH_TABLE_ITER;
+
+XML_NONTESTING_STATIC NAMED *lookupWithLength(XML_Parser parser,
+                                              HASH_TABLE *table, KEY name,
+                                              size_t nameLen,
+                                              size_t createSize);
+XML_NONTESTING_STATIC NAMED *lookup(XML_Parser parser, HASH_TABLE *table,
+                                    KEY name, size_t createSize);
+
+XML_NONTESTING_STATIC void hashTableInit(HASH_TABLE *table, XML_Parser parser);
+XML_NONTESTING_STATIC void hashTableClear(HASH_TABLE *table);
+XML_NONTESTING_STATIC void hashTableDestroy(HASH_TABLE *table);
+XML_NONTESTING_STATIC void hashTableIterInit(HASH_TABLE_ITER *iter,
+                                             const HASH_TABLE *table);
+XML_NONTESTING_STATIC NAMED *hashTableIterNext(HASH_TABLE_ITER *iter);
+
+XML_NONTESTING_STATIC XML_Bool keyeq(KEY s1, size_t s1len, KEY s2);
+XML_NONTESTING_STATIC size_t keylen(KEY s);
+
+#endif // ! defined(HASH_TABLE_H)

Modules/pyexpat.c

@@ -2552,7 +2552,10 @@ pyexpat_exec(PyObject *mod)
     capi->SetEncoding = XML_SetEncoding;
     capi->DefaultUnknownEncodingHandler = PyUnknownEncodingHandler;
 #if XML_COMBINED_VERSION >= 20100
+_Py_COMP_DIAG_PUSH
+_Py_COMP_DIAG_IGNORE_DEPR_DECLS
     capi->SetHashSalt = XML_SetHashSalt;
+_Py_COMP_DIAG_POP
 #else
     capi->SetHashSalt = NULL;
 #endif