Make nullsafe op on undef variable consistent

with undefined variable behavior in the language.

Author: iluuu1994

Zend/tests/nullsafe_operator/018.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Test nullsafe on undefined variable
+--FILE--
+<?php
+
+var_dump($foo?->bar = 10);
+var_dump($foo?->bar());
+var_dump($foo);
+
+?>
+--EXPECTF--
+Warning: Undefined variable $foo in %s.php on line 3
+NULL
+
+Warning: Undefined variable $foo in %s.php on line 4
+NULL
+
+Warning: Undefined variable $foo in %s.php on line 5
+NULL

Zend/zend_vm_def.h

@@ -7037,12 +7037,20 @@ ZEND_VM_HOT_NOCONST_HANDLER(195, ZEND_JMP_NULL, CONST|TMPVAR|CV, JMP_ADDR)
 
 	val = GET_OP1_ZVAL_PTR_UNDEF(BP_VAR_R);
 
-	if (Z_TYPE_INFO_P(val) != IS_NULL) {
+	if (Z_TYPE_INFO_P(val) > IS_NULL) {
 		ZEND_VM_NEXT_OPCODE();
 	} else {
 		zval *result = EX_VAR(opline->result.var);
 
 		if (EXPECTED(opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_EXPR)) {
+			if (UNEXPECTED(Z_TYPE_INFO_P(val) == IS_UNDEF)) {
+				SAVE_OPLINE();
+				ZVAL_UNDEFINED_OP1();
+				if (UNEXPECTED(EG(exception) != NULL)) {
+					HANDLE_EXCEPTION();
+				}
+			}
+
 			ZVAL_NULL(result);
 		} else if (opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_ISSET) {
 			ZVAL_BOOL(result, 0);

Zend/zend_vm_execute.h

@@ -4290,12 +4290,20 @@ static ZEND_VM_COLD ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_JMP_NULL_SPEC_CON
 
 	val = RT_CONSTANT(opline, opline->op1);
 
-	if (Z_TYPE_INFO_P(val) != IS_NULL) {
+	if (Z_TYPE_INFO_P(val) > IS_NULL) {
 		ZEND_VM_NEXT_OPCODE();
 	} else {
 		zval *result = EX_VAR(opline->result.var);
 
 		if (EXPECTED(opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_EXPR)) {
+			if (UNEXPECTED(Z_TYPE_INFO_P(val) == IS_UNDEF)) {
+				SAVE_OPLINE();
+				ZVAL_UNDEFINED_OP1();
+				if (UNEXPECTED(EG(exception) != NULL)) {
+					HANDLE_EXCEPTION();
+				}
+			}
+
 			ZVAL_NULL(result);
 		} else if (opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_ISSET) {
 			ZVAL_BOOL(result, 0);
@@ -13201,12 +13209,20 @@ static ZEND_VM_HOT ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_JMP_NULL_SPEC_TMPV
 
 	val = _get_zval_ptr_var(opline->op1.var EXECUTE_DATA_CC);
 
-	if (Z_TYPE_INFO_P(val) != IS_NULL) {
+	if (Z_TYPE_INFO_P(val) > IS_NULL) {
 		ZEND_VM_NEXT_OPCODE();
 	} else {
 		zval *result = EX_VAR(opline->result.var);
 
 		if (EXPECTED(opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_EXPR)) {
+			if (UNEXPECTED(Z_TYPE_INFO_P(val) == IS_UNDEF)) {
+				SAVE_OPLINE();
+				ZVAL_UNDEFINED_OP1();
+				if (UNEXPECTED(EG(exception) != NULL)) {
+					HANDLE_EXCEPTION();
+				}
+			}
+
 			ZVAL_NULL(result);
 		} else if (opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_ISSET) {
 			ZVAL_BOOL(result, 0);
@@ -36586,12 +36602,20 @@ static ZEND_VM_HOT ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_JMP_NULL_SPEC_CV_H
 
 	val = EX_VAR(opline->op1.var);
 
-	if (Z_TYPE_INFO_P(val) != IS_NULL) {
+	if (Z_TYPE_INFO_P(val) > IS_NULL) {
 		ZEND_VM_NEXT_OPCODE();
 	} else {
 		zval *result = EX_VAR(opline->result.var);
 
 		if (EXPECTED(opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_EXPR)) {
+			if (UNEXPECTED(Z_TYPE_INFO_P(val) == IS_UNDEF)) {
+				SAVE_OPLINE();
+				ZVAL_UNDEFINED_OP1();
+				if (UNEXPECTED(EG(exception) != NULL)) {
+					HANDLE_EXCEPTION();
+				}
+			}
+
 			ZVAL_NULL(result);
 		} else if (opline->extended_value == ZEND_SHORT_CIRCUITING_CHAIN_ISSET) {
 			ZVAL_BOOL(result, 0);