Disable MI_DEBUG in ASAN builds

Include/internal/pycore_mimalloc.h

@@ -14,11 +14,31 @@
 #define MI_DEBUG_FREED      PYMEM_DEADBYTE
 #define MI_DEBUG_PADDING    PYMEM_FORBIDDENBYTE
 
+ /* ASAN builds don't use MI_DEBUG. ASAN + MI_DEBUG triggers additional
+  * checks, which can cause mimalloc to print warnings to stderr. The
+  * warnings break some tests.
+  *
+  *   mi_usable_size: pointer might not point to a valid heap region:
+  *   ...
+  *   yes, the previous pointer ... was valid after all
+  */
+#if defined(__has_feature)
+#  if __has_feature(address_sanitizer)
+#    define MI_DEBUG 0
+#  endif
+#elif defined(__GNUC__) && defined(__SANITIZE_ADDRESS__)
+#  define MI_DEBUG 0
+#endif
+
+/* Perform additional checks in debug builds, see mimalloc-types.h
+ * - enable basic and internal assertion checks with MI_DEBUG 2
+ * - check for double free, invalid pointer free
+ * - use guard pages to check for buffer overflows
+ */
 #ifdef Py_DEBUG
-// see mimalloc-types.h
-// basic and internal assertion checks
-#  define MI_DEBUG 2
-// check for double free, buffer overflows and invalid pointer free
+#  ifndef MI_DEBUG
+#    define MI_DEBUG 2
+#  endif
 #  define MI_SECURE 4
 #elif defined(PY_MIMALLOC_SECURE)
 #  define MI_SECURE PY_MIMALLOC_SECURE

Objects/obmalloc.c

@@ -136,18 +136,6 @@ _PyMem_RawFree(void *Py_UNUSED(ctx), void *ptr)
 
 #ifdef WITH_MIMALLOC
 
-static void
-_PyMimalloc_Config(void) {
-    /* XXX Some options cannot be changed because
-       PyRuntime_Initialize() -> alloc_for_runtime()
-       allocates memory, which initializes mimalloc.
-
-       verbose logging breaks some tests in debug mode:
-       "pointer might not point to a valid heap region"
-    */
-    mi_option_disable(mi_option_verbose);
-}
-
 static void *
 _PyMimalloc_Malloc(void *ctx, size_t size)
 {
@@ -442,9 +430,6 @@ _PyMem_SetupAllocators(PyMemAllocatorName allocator)
             PyMem_SetupDebugHooks();
         }
 
-        // set global mimalloc flags
-        _PyMimalloc_Config();
-
         break;
     }
 #endif