Merge branch 'PHP-7.4'

* PHP-7.4:
  Fixed bug #79784

diff --cc Zend/zend_execute.c
index f49b005a14e3549f1fcbe4aa49acaf2ad3ec4163,5aed92ff45250e3d0f6af93d3e833120b0389042..bd4ce8fa7e685fb14bcdfee8ea8846822d6d6e55
--- 1/Zend/zend_execute.c
--- 2/Zend/zend_execute.c
+++ b/Zend/zend_execute.c
@@@ -2010,18 -2060,32 +2010,31 @@@ static ZEND_COLD void zend_binary_assig
                        zend_check_string_offset(dim, BP_VAR_RW EXECUTE_DATA_CC);
                        zend_wrong_string_offset(EXECUTE_DATA_C);
                }
 -      } else if (EXPECTED(!Z_ISERROR_P(container))) {
 +      } else {
                zend_use_scalar_as_array();
        }
 -      get_op_data_zval_ptr_r((opline+1)->op1_type, (opline+1)->op1, &free_op_data1);
 -      FREE_OP(free_op_data1);
 +      FREE_OP((opline+1)->op1_type, (opline+1)->op1.var);
  }
  
- static zend_never_inline zend_uchar slow_index_convert(const zval *dim, zend_value *value EXECUTE_DATA_DC)
+ static zend_never_inline zend_uchar slow_index_convert(HashTable *ht, const zval *dim, zend_value *value EXECUTE_DATA_DC)
  {
        switch (Z_TYPE_P(dim)) {
-               case IS_UNDEF:
+               case IS_UNDEF: {
+                       /* The array may be destroyed while throwing the notice.
+                        * Temporarily increase the refcount to detect this situation. */
+                       if (!(GC_FLAGS(ht) & IS_ARRAY_IMMUTABLE)) {
+                               GC_ADDREF(ht);
+                       }
                        ZVAL_UNDEFINED_OP2();
+                       if (!(GC_FLAGS(ht) & IS_ARRAY_IMMUTABLE) && !GC_DELREF(ht)) {
+                               zend_array_destroy(ht);
+                               return IS_NULL;
+                       }
+                       if (EG(exception)) {
+                               return IS_NULL;
+                       }
                        /* break missing intentionally */
+               }
                case IS_NULL:
                        value->str = ZSTR_EMPTY_ALLOC();
                        return IS_STRING;