[perl #55640] [BUG] [PATCH] oo_get_class segfaults

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I've found a bug in oo_get_class, it segfaults when calling pmc_type
with a NULL STIRNG *

This short pir code shows the problem:

.sub main
  $P0= get_root_namespace
  $P1= get_class $P0
.end

The attached patch fixes it.

-- 
Salu2

Index: src/oo.c
===================================================================
--- src/oo.c	(revisión: 28239)
+++ src/oo.c	(copia de trabajo)
@@ -236,15 +236,21 @@
 
     if (PMC_IS_NULL(classobj)) {
         /* Look up a low-level class and create a proxy */
-        const INTVAL type = pmc_type(interp, VTABLE_get_string(interp, key));
-
-        /* Reject invalid type numbers */
-        if (type > interp->n_vtable_max || type <= 0)
+        STRING * tname = VTABLE_get_string(interp, key);
+        if (! tname) {
             return PMCNULL;
+        }
         else {
-             PMC * const type_num = pmc_new(interp, enum_class_Integer);
-             VTABLE_set_integer_native(interp, type_num, type);
-             classobj = pmc_new_init(interp, enum_class_PMCProxy, type_num);
+            const INTVAL type = pmc_type(interp, tname);
+
+            /* Reject invalid type numbers */
+            if (type > interp->n_vtable_max || type <= 0)
+                return PMCNULL;
+            else {
+                 PMC * const type_num = pmc_new(interp, enum_class_Integer);
+                 VTABLE_set_integer_native(interp, type_num, type);
+                 classobj = pmc_new_init(interp, enum_class_PMCProxy, type_num);
+            }
         }
     }