Do not use PyBytes_FromObject if NULL was passed to PyObject_Bytes

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/cext/PythonCextObjectBuiltins.java

@@ -74,6 +74,7 @@
 import com.oracle.graal.python.builtins.modules.cext.PythonCextBytesBuiltins.PyBytes_FromObject;
 import com.oracle.graal.python.builtins.objects.PNone;
 import com.oracle.graal.python.builtins.objects.PNotImplemented;
+import com.oracle.graal.python.builtins.objects.bytes.BytesUtils;
 import com.oracle.graal.python.builtins.objects.bytes.PBytesLike;
 import com.oracle.graal.python.builtins.objects.cext.capi.CApiContext;
 import com.oracle.graal.python.builtins.objects.cext.capi.CApiGuards;
@@ -478,9 +479,12 @@ static Object bytes(Object obj,
         }
 
         @Specialization(guards = "isNoValue(obj)")
-        static Object bytesNoValue(@SuppressWarnings("unused") Object obj,
-                        @Cached PyBytes_FromObject fromObjectNode) {
-            return fromObjectNode.execute(StringLiterals.T_NULL_RESULT);
+        Object bytesNoValue(@SuppressWarnings("unused") Object obj) {
+            /*
+             * Note: CPython calls PyBytes_FromString("<NULL>") but we do not directly have it.
+             * Therefore, we directly create the bytes object with string "<NULL>" here.
+             */
+            return factory().createBytes(BytesUtils.NULL_STRING);
         }
 
         protected static boolean hasBytes(Object obj, PyObjectLookupAttr lookupAttrNode) {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/bytes/BytesUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2022, Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2023, Oracle and/or its affiliates.
  * Copyright (c) 2014, Regents of the University of California
  *
  * All rights reserved.
@@ -39,6 +39,9 @@ public final class BytesUtils {
 
     @CompilationFinal(dimensions = 1) public static final byte[] HEXDIGITS = "0123456789abcdef".getBytes();
 
+    /** Bytes of ASCII string {@code "<NULL>"} */
+    @CompilationFinal(dimensions = 1) public static final byte[] NULL_STRING = {60, 78, 85, 76, 76, 62};
+
     // tables are copied from CPython/Python/pyctype.c
     static final byte PY_CTF_LOWER = 0x01;
     static final byte PY_CTF_UPPER = 0x02;