Refactor: libcrmcommon: Drop xmlSetBufferAllocationScheme() call

As of libxml v2.14.0, xmlSetBufferAllocationScheme() is deprecated,
which is already causing compilation failures on debian-experimental.
Further, also as of libxml v2.14.0, its replacement
xmlBufferSetAllocationScheme() is a no-op.

At this point, we could easily drop pcmk__xml_init(), replacing it with
calls to pcmk__schema_init(). However, pcmk__xml_cleanup() still seems
reasonable to have, and it seems intuitive to keep a corresponding
init() function. So for now this remains as a wrapper.

Signed-off-by: Reid Wahl <[email protected]>

Author: nrwahl2

lib/common/tests/xml/pcmk__xml_init_test.c

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023-2024 the Pacemaker project contributors
+ * Copyright 2023-2025 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
@@ -13,19 +13,12 @@
 
 #include "crmcommon_private.h"
 
-static void
-buffer_scheme_test(void **state)
-{
-    assert_int_equal(XML_BUFFER_ALLOC_DOUBLEIT, xmlGetBufferAllocationScheme());
-}
-
 static void
 schemas_initialized(void **state)
 {
     assert_non_null(pcmk__find_x_0_schema());
 }
 
-// The group setup/teardown functions call pcmk__xml_init()/pcmk__cml_xleanup()
+// The group setup/teardown functions call pcmk__xml_init()/pcmk__xml_cleanup()
 PCMK__UNIT_TEST(pcmk__xml_test_setup_group, pcmk__xml_test_teardown_group,
-                cmocka_unit_test(buffer_scheme_test),
                 cmocka_unit_test(schemas_initialized))

lib/common/unittest.c

@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 the Pacemaker project contributors
+ * Copyright 2024-2025 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
@@ -84,7 +84,7 @@ pcmk__assert_validates(xmlNode *xml)
 int
 pcmk__xml_test_setup_group(void **state)
 {
-    // Load schemas and set libxml2 buffer allocation scheme
+    // Load schemas
     pcmk__xml_init();
     return 0;
 }

lib/common/xml.c

@@ -1423,8 +1423,7 @@ xml_calculate_changes(xmlNode *old_xml, xmlNode *new_xml)
  * \internal
  * \brief Initialize the Pacemaker XML environment
  *
- * Set an XML buffer allocation scheme, set XML node create and destroy
- * callbacks, and load schemas into the cache.
+ * Currently this only loads schemas into the cache. It used to do more.
  */
 void
 pcmk__xml_init(void)
@@ -1435,12 +1434,6 @@ pcmk__xml_init(void)
     if (!initialized) {
         initialized = true;
 
-        /* Double the buffer size when the buffer needs to grow. The default
-         * allocator XML_BUFFER_ALLOC_EXACT was found to cause poor performance
-         * due to the number of reallocs.
-         */
-        xmlSetBufferAllocationScheme(XML_BUFFER_ALLOC_DOUBLEIT);
-
         // Load schemas into the cache
         pcmk__schema_init();
     }