Core: fix missing deprecation when accessing null array key with JIT (#20883)

NEWS

@@ -7,6 +7,8 @@ PHP                                                                        NEWS
   . Fixed bug GH-21059 (Segfault when preloading constant AST closure). (ilutov)
   . Fixed bug GH-21072 (Crash on (unset) cast in constant expression).
     (arshidkv12)
+  . Fix deprecation now showing when accessing null key of an array with JIT.
+    (alexandre-daubois)
 
 - Windows:
   . Fixed compilation with clang (missing intrin.h include). (Kévin Dunglas)

Zend/Optimizer/sccp.c

@@ -363,8 +363,7 @@ static inline zend_result zval_to_string_offset(zend_long *result, zval *op) {
 static inline zend_result fetch_array_elem(zval **result, zval *op1, zval *op2) {
 	switch (Z_TYPE_P(op2)) {
 		case IS_NULL:
-			*result = zend_hash_find(Z_ARR_P(op1), ZSTR_EMPTY_ALLOC());
-			return SUCCESS;
+			return FAILURE;
 		case IS_FALSE:
 			*result = zend_hash_index_find(Z_ARR_P(op1), 0);
 			return SUCCESS;

ext/opcache/tests/jit/fetch_dim_r_001.phpt

@@ -30,7 +30,7 @@ function foo() {
 }
 foo();
 ?>
---EXPECT--
+--EXPECTF--
 int(1)
 int(3)
 int(2)
@@ -38,6 +38,8 @@ int(1)
 int(3)
 int(1)
 int(2)
+
+Deprecated: Using null as an array offset is deprecated, use an empty string instead in %s on line %d
 int(4)
 int(5)
 int(5)