Merge branch 'PHP-8.4'

* PHP-8.4:
  pdo_odbc: Fix memory leak if WideCharToMultiByte() fails
  Fix memory leak on php_odbc_fetch_hash() failure
  Do not delete main chunk in zend_gc

Author: ndossche

Zend/tests/gh18756.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Bug GH-18756: Zend MM may delete the main chunk
+--EXTENSIONS--
+zend_test
+--FILE--
+<?php
+
+zend_test_gh18756();
+
+?>
+==DONE==
+--EXPECT--
+==DONE==

Zend/zend_alloc.c

@@ -2192,7 +2192,7 @@ ZEND_API size_t zend_mm_gc(zend_mm_heap *heap)
 				i++;
 			}
 		}
-		if (chunk->free_pages == ZEND_MM_PAGES - ZEND_MM_FIRST_PAGE) {
+		if (chunk->free_pages == ZEND_MM_PAGES - ZEND_MM_FIRST_PAGE && chunk != heap->main_chunk) {
 			zend_mm_chunk *next_chunk = chunk->next;
 
 			zend_mm_delete_chunk(heap, chunk);

ext/odbc/php_odbc.c

@@ -1461,6 +1461,7 @@ static void php_odbc_fetch_hash(INTERNAL_FUNCTION_PARAMETERS, int result_type)
 				if (rc == SQL_ERROR) {
 					odbc_sql_error(result->conn_ptr, result->stmt, "SQLGetData");
 					efree(buf);
+					zval_ptr_dtor(return_value);
 					RETURN_FALSE;
 				}
 

ext/pdo_odbc/odbc_stmt.c

@@ -103,6 +103,7 @@ static int pdo_odbc_ucs22utf8(int is_unicode, zval *result)
 		zend_string *str = zend_string_alloc(ret, 0);
 		ret = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR) Z_STRVAL_P(result), Z_STRLEN_P(result)/sizeof(WCHAR), ZSTR_VAL(str), ZSTR_LEN(str), NULL, NULL);
 		if (ret == 0) {
+			zend_string_efree(str);
 			return PDO_ODBC_CONV_FAIL;
 		}
 

ext/zend_test/test.c

@@ -1613,3 +1613,13 @@ static PHP_FUNCTION(zend_test_compile_to_ast)
 
 	RETVAL_STR(result);
 }
+
+static PHP_FUNCTION(zend_test_gh18756)
+{
+	ZEND_PARSE_PARAMETERS_NONE();
+
+	zend_mm_heap *heap = zend_mm_startup();
+	zend_mm_gc(heap);
+	zend_mm_gc(heap);
+	zend_mm_shutdown(heap, true, false);
+}

ext/zend_test/test.stub.php

@@ -334,6 +334,8 @@ function zend_test_is_zend_ptr(int $addr): bool {}
     function zend_test_log_err_debug(string $str): void {}
 
     function zend_test_compile_to_ast(string $str): string {}
+
+    function zend_test_gh18756(): void {}
 }
 
 namespace ZendTestNS {