Warn when coercing NAN to other types

Girgias · Girgias · commit 656be82adda2 · 2025-08-31T18:56:08.000+02:00
RFC: https://wiki.php.net/rfc/warnings-php-8-5#coercing_nan_to_other_types
diff --git a/Zend/tests/runtime_compile_time_binary_operands.phpt b/Zend/tests/runtime_compile_time_binary_operands.phpt
@@ -8,7 +8,7 @@ if (getenv("SKIP_SLOW_TESTS")) die('skip slow test');
 ?>
 --FILE--
 <?php
-error_reporting(E_ALL ^ E_DEPRECATED);
+error_reporting(E_ALL ^ E_DEPRECATED ^ E_WARNING);
 
 $binaryOperators = [
     "==",
diff --git a/Zend/tests/type_coercion/float_to_int/explicit_casts_should_not_warn.phpt b/Zend/tests/type_coercion/float_to_int/explicit_casts_should_not_warn.phpt
@@ -1,5 +1,5 @@
 --TEST--
-Explicit (int) cast must not warn
+Explicit (int) cast must not warn (except for NAN)
 --SKIPIF--
 <?php
 if (PHP_INT_SIZE != 8) die("skip this test is for 64bit platform only");
@@ -12,12 +12,10 @@ $values =[
     3.5,
     10e120,
     10e300,
-    fdiv(0, 0),
     (string) 3.0,
     (string) 3.5,
     (string) 10e120,
     (string) 10e300,
-    (string) fdiv(0, 0),
 ];
 
 foreach($values as $value) {
@@ -30,9 +28,7 @@ int(3)
 int(3)
 int(0)
 int(0)
-int(0)
 int(3)
 int(3)
 int(9223372036854775807)
 int(9223372036854775807)
-int(0)
diff --git a/Zend/tests/type_coercion/float_to_int/explicit_casts_should_not_warn_32bit.phpt b/Zend/tests/type_coercion/float_to_int/explicit_casts_should_not_warn_32bit.phpt
@@ -1,5 +1,5 @@
 --TEST--
-Explicit (int) cast must not warn 32bit variation
+Explicit (int) cast must not warn (except for NAN) 32bit variation
 --SKIPIF--
 <?php
 if (PHP_INT_SIZE != 4) die("skip this test is for 32bit platform only");
@@ -12,12 +12,10 @@ $values =[
     3.5,
     10e120,
     10e300,
-    fdiv(0, 0),
     (string) 3.0,
     (string) 3.5,
     (string) 10e120,
     (string) 10e300,
-    (string) fdiv(0, 0),
 ];
 
 foreach($values as $value) {
@@ -30,9 +28,7 @@ int(3)
 int(3)
 int(0)
 int(0)
-int(0)
 int(3)
 int(3)
 int(2147483647)
 int(2147483647)
-int(0)
diff --git a/Zend/tests/type_coercion/float_to_int/union_int_string_type_arg.phpt b/Zend/tests/type_coercion/float_to_int/union_int_string_type_arg.phpt
@@ -23,6 +23,8 @@ int(1)
 
 Deprecated: Implicit conversion from float 1.5 to int loses precision in %s on line %d
 int(1)
+
+Warning: unexpected NAN value was coerced to string in %s on line %d
 string(3) "NAN"
 string(8) "1.0E+121"
 string(3) "INF"
diff --git a/Zend/tests/type_coercion/int_special_values.phpt b/Zend/tests/type_coercion/int_special_values.phpt
@@ -8,7 +8,6 @@ $values = [
     -INF,
     1 / INF,
     -1 / INF, // Negative zero,
-    NAN
 ];
 
 foreach($values as $value) {
@@ -32,6 +31,3 @@ int(0)
 
 float(-0)
 int(0)
-
-float(NAN)
-int(0)
diff --git a/Zend/tests/type_coercion/nan_to_other.phpt b/Zend/tests/type_coercion/nan_to_other.phpt
@@ -40,27 +40,53 @@ foreach ($types as $type) {
 ?>
 --EXPECTF--
 float(NAN)
+
+Warning: unexpected NAN value was coerced to bool in %s on line %d
 bool(true)
+
+Warning: unexpected NAN value was coerced to string in %s on line %d
 string(3) "NAN"
+
+Warning: unexpected NAN value was coerced to int in %s on line %d
 int(0)
+
+Warning: unexpected NAN value was coerced to bool in %s on line %d
 bool(true)
+
+Warning: unexpected NAN value was coerced to string in %s on line %d
 string(3) "NAN"
+
+Warning: unexpected NAN value was coerced to array in %s on line %d
 array(1) {
   [0]=>
   float(NAN)
 }
+
+Warning: unexpected NAN value was coerced to object in %s on line %d
 object(stdClass)#%d (1) {
   ["scalar"]=>
   float(NAN)
 }
+
+Warning: unexpected NAN value was coerced to null in %s on line %d
 NULL
+
+Warning: unexpected NAN value was coerced to bool in %s on line %d
 bool(true)
+
+Warning: unexpected NAN value was coerced to int in %s on line %d
 int(0)
+
+Warning: unexpected NAN value was coerced to string in %s on line %d
 string(3) "NAN"
+
+Warning: unexpected NAN value was coerced to array in %s on line %d
 array(1) {
   [0]=>
   float(NAN)
 }
+
+Warning: unexpected NAN value was coerced to object in %s on line %d
 object(stdClass)#%d (1) {
   ["scalar"]=>
   float(NAN)
diff --git a/Zend/tests/type_declarations/scalar_basic.phpt b/Zend/tests/type_declarations/scalar_basic.phpt
@@ -194,6 +194,7 @@ string(0) ""
 string(%d) "%d"
 
 *** Trying float(NAN)
+E_WARNING: unexpected NAN value was coerced to string on line %d
 string(3) "NAN"
 
 *** Trying bool(true)
@@ -247,6 +248,7 @@ bool(false)
 bool(true)
 
 *** Trying float(NAN)
+E_WARNING: unexpected NAN value was coerced to bool on line %d
 bool(true)
 
 *** Trying bool(true)
diff --git a/Zend/tests/type_declarations/scalar_return_basic.phpt b/Zend/tests/type_declarations/scalar_return_basic.phpt
@@ -156,6 +156,7 @@ string(0) ""
 *** Trying int(2147483647)
 string(10) "2147483647"
 *** Trying float(NAN)
+E_WARNING: unexpected NAN value was coerced to string on line %d
 string(3) "NAN"
 *** Trying bool(true)
 string(1) "1"
@@ -193,6 +194,7 @@ bool(false)
 *** Trying int(2147483647)
 bool(true)
 *** Trying float(NAN)
+E_WARNING: unexpected NAN value was coerced to bool on line %d
 bool(true)
 *** Trying bool(true)
 bool(true)
diff --git a/Zend/tests/type_declarations/scalar_return_basic_64bit.phpt b/Zend/tests/type_declarations/scalar_return_basic_64bit.phpt
@@ -156,6 +156,7 @@ string(0) ""
 *** Trying int(9223372036854775807)
 string(19) "9223372036854775807"
 *** Trying float(NAN)
+E_WARNING: unexpected NAN value was coerced to string on line %d
 string(3) "NAN"
 *** Trying bool(true)
 string(1) "1"
@@ -193,6 +194,7 @@ bool(false)
 *** Trying int(9223372036854775807)
 bool(true)
 *** Trying float(NAN)
+E_WARNING: unexpected NAN value was coerced to bool on line %d
 bool(true)
 *** Trying bool(true)
 bool(true)
diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
@@ -10210,6 +10210,7 @@ static void zend_compile_binary_op(znode *result, zend_ast *ast) /* {{{ */
 	}
 
 	do {
+		// TODO do not do this for NAN?
 		if (opcode == ZEND_IS_EQUAL || opcode == ZEND_IS_NOT_EQUAL) {
 			if (left_node.op_type == IS_CONST) {
 				if (Z_TYPE(left_node.u.constant) == IS_FALSE) {
diff --git a/Zend/zend_operators.c b/Zend/zend_operators.c
@@ -669,6 +669,9 @@ ZEND_API void ZEND_FASTCALL convert_to_double(zval *op) /* {{{ */
 
 ZEND_API void ZEND_FASTCALL convert_to_null(zval *op) /* {{{ */
 {
+	if (UNEXPECTED(Z_TYPE_P(op) == IS_DOUBLE && zend_isnan(Z_DVAL_P(op)))) {
+		zend_nan_coerced_to_type_warning(IS_NULL);
+	}
 	zval_ptr_dtor(op);
 	ZVAL_NULL(op);
 }
@@ -697,6 +700,9 @@ ZEND_API void ZEND_FASTCALL convert_to_boolean(zval *op) /* {{{ */
 			ZVAL_BOOL(op, Z_LVAL_P(op) ? 1 : 0);
 			break;
 		case IS_DOUBLE:
+			if (UNEXPECTED(zend_isnan(Z_DVAL_P(op)))) {
+				zend_nan_coerced_to_type_warning(_IS_BOOL);
+			}
 			ZVAL_BOOL(op, Z_DVAL_P(op) ? 1 : 0);
 			break;
 		case IS_STRING:
@@ -810,6 +816,9 @@ ZEND_API bool ZEND_FASTCALL _try_convert_to_string(zval *op) /* {{{ */
 
 static void convert_scalar_to_array(zval *op) /* {{{ */
 {
+	if (UNEXPECTED(Z_TYPE_P(op) == IS_DOUBLE && zend_isnan(Z_DVAL_P(op)))) {
+		zend_nan_coerced_to_type_warning(IS_ARRAY);
+	}
 	HashTable *ht = zend_new_array(1);
 	zend_hash_index_add_new(ht, 0, op);
 	ZVAL_ARR(op, ht);
@@ -892,6 +901,11 @@ ZEND_API void ZEND_FASTCALL convert_to_object(zval *op) /* {{{ */
 		case IS_REFERENCE:
 			zend_unwrap_reference(op);
 			goto try_again;
+		case IS_DOUBLE:
+			if (UNEXPECTED(zend_isnan(Z_DVAL_P(op)))) {
+				zend_nan_coerced_to_type_warning(IS_OBJECT);
+			}
+			ZEND_FALLTHROUGH;
 		default: {
 			zval tmp;
 			ZVAL_COPY_VALUE(&tmp, op);
@@ -912,6 +926,11 @@ ZEND_API void ZEND_COLD zend_incompatible_string_to_long_error(const zend_string
 	zend_error(E_DEPRECATED, "Implicit conversion from float-string \"%s\" to int loses precision", ZSTR_VAL(s));
 }
 
+ZEND_API void ZEND_COLD zend_nan_coerced_to_type_warning(uint8_t type)
+{
+	zend_error(E_WARNING, "unexpected NAN value was coerced to %s", zend_get_type_by_const(type));
+}
+
 ZEND_API zend_long ZEND_FASTCALL zval_get_long_func(const zval *op, bool is_strict) /* {{{ */
 {
 try_again:
@@ -2246,6 +2265,8 @@ static int compare_double_to_string(double dval, zend_string *str) /* {{{ */
 	double str_dval;
 	uint8_t type = is_numeric_string(ZSTR_VAL(str), ZSTR_LEN(str), &str_lval, &str_dval, 0);
 
+	ZEND_ASSERT(!zend_isnan(dval));
+
 	if (type == IS_LONG) {
 		return ZEND_THREEWAY_COMPARE(dval, (double) str_lval);
 	}
@@ -2264,7 +2285,7 @@ static int compare_double_to_string(double dval, zend_string *str) /* {{{ */
 
 ZEND_API int ZEND_FASTCALL zend_compare(zval *op1, zval *op2) /* {{{ */
 {
-	int converted = 0;
+	bool converted = false;
 	zval op1_copy, op2_copy;
 
 	while (1) {
@@ -2371,6 +2392,13 @@ ZEND_API int ZEND_FASTCALL zend_compare(zval *op1, zval *op2) /* {{{ */
 				}
 
 				if (!converted) {
+					/* Handle NAN */
+					if (
+						(Z_TYPE_P(op1) == IS_DOUBLE && zend_isnan(Z_DVAL_P(op1)))
+						|| (Z_TYPE_P(op2) == IS_DOUBLE && zend_isnan(Z_DVAL_P(op2)))
+					) {
+						return 1;
+					}
 					if (Z_TYPE_P(op1) < IS_TRUE) {
 						return zval_is_true(op2) ? -1 : 0;
 					} else if (Z_TYPE_P(op1) == IS_TRUE) {
@@ -2385,7 +2413,7 @@ ZEND_API int ZEND_FASTCALL zend_compare(zval *op1, zval *op2) /* {{{ */
 						if (EG(exception)) {
 							return 1; /* to stop comparison of arrays */
 						}
-						converted = 1;
+						converted = true;
 					}
 				} else if (Z_TYPE_P(op1)==IS_ARRAY) {
 					return 1;
@@ -3543,6 +3571,9 @@ ZEND_API zend_string* ZEND_FASTCALL zend_double_to_str(double num)
 	int precision = (int) EG(precision);
 	zend_gcvt(num, precision ? precision : 1, '.', 'E', buf);
 	zend_string *str =  zend_string_init(buf, strlen(buf), 0);
+	if (UNEXPECTED(zend_string_equals_literal(str, "NAN"))) {
+		zend_nan_coerced_to_type_warning(IS_STRING);
+	}
 	GC_ADD_FLAGS(str, IS_STR_VALID_UTF8);
 	return str;
 }
diff --git a/Zend/zend_operators.h b/Zend/zend_operators.h
@@ -115,11 +115,18 @@ ZEND_API const char* ZEND_FASTCALL zend_memnrstr_ex(const char *haystack, const
 #	define ZEND_DOUBLE_FITS_LONG(d) (!((d) >= (double)ZEND_LONG_MAX || (d) < (double)ZEND_LONG_MIN))
 #endif
 
+ZEND_API void zend_incompatible_double_to_long_error(double d);
+ZEND_API void zend_incompatible_string_to_long_error(const zend_string *s);
+ZEND_API void ZEND_COLD zend_nan_coerced_to_type_warning(uint8_t type);
+
 ZEND_API zend_long ZEND_FASTCALL zend_dval_to_lval_slow(double d);
 
 static zend_always_inline zend_long zend_dval_to_lval(double d)
 {
 	if (UNEXPECTED(!zend_finite(d)) || UNEXPECTED(zend_isnan(d))) {
+		if (zend_isnan(d)) {
+			zend_nan_coerced_to_type_warning(IS_LONG);
+		}
 		return 0;
 	} else if (!ZEND_DOUBLE_FITS_LONG(d)) {
 		return zend_dval_to_lval_slow(d);
@@ -131,6 +138,9 @@ static zend_always_inline zend_long zend_dval_to_lval(double d)
 static zend_always_inline zend_long zend_dval_to_lval_cap(double d)
 {
 	if (UNEXPECTED(!zend_finite(d)) || UNEXPECTED(zend_isnan(d))) {
+		if (zend_isnan(d)) {
+			zend_nan_coerced_to_type_warning(IS_LONG);
+		}
 		return 0;
 	} else if (!ZEND_DOUBLE_FITS_LONG(d)) {
 		return (d > 0 ? ZEND_LONG_MAX : ZEND_LONG_MIN);
@@ -143,9 +153,6 @@ static zend_always_inline bool zend_is_long_compatible(double d, zend_long l) {
 	return (double)l == d;
 }
 
-ZEND_API void zend_incompatible_double_to_long_error(double d);
-ZEND_API void zend_incompatible_string_to_long_error(const zend_string *s);
-
 static zend_always_inline zend_long zend_dval_to_lval_safe(double d)
 {
 	zend_long l = zend_dval_to_lval(d);
@@ -405,6 +412,9 @@ static zend_always_inline bool i_zend_is_true(const zval *op)
 			}
 			break;
 		case IS_DOUBLE:
+			if (UNEXPECTED(zend_isnan(Z_DVAL_P(op)))) {
+				zend_nan_coerced_to_type_warning(_IS_BOOL);
+			}
 			if (Z_DVAL_P(op)) {
 				result = 1;
 			}
diff --git a/ext/opcache/tests/jit/nan_001.phpt b/ext/opcache/tests/jit/nan_001.phpt
@@ -13,7 +13,12 @@ for ($i = 0; $i < 3; $i++) {
     else { echo "nan is false\n"; }
 }	
 ?>
---EXPECT--
+--EXPECTF--
+Warning: unexpected NAN value was coerced to bool in %s on line %d
 nan is true
+
+Warning: unexpected NAN value was coerced to bool in %s on line %d
 nan is true
+
+Warning: unexpected NAN value was coerced to bool in %s on line %d
 nan is true
diff --git a/ext/opcache/tests/jit/nan_002.phpt b/ext/opcache/tests/jit/nan_002.phpt
diff --git a/ext/standard/tests/array/range/range_inputs_float_NAN_values.phpt b/ext/standard/tests/array/range/range_inputs_float_NAN_values.phpt
diff --git a/ext/standard/tests/general_functions/get_defined_constants_basic.phpt b/ext/standard/tests/general_functions/get_defined_constants_basic.phpt
diff --git a/ext/standard/tests/math/fpow.phpt b/ext/standard/tests/math/fpow.phpt
diff --git a/ext/standard/tests/math/pow_basic.phpt b/ext/standard/tests/math/pow_basic.phpt
diff --git a/ext/standard/tests/math/pow_basic_64bit.phpt b/ext/standard/tests/math/pow_basic_64bit.phpt

Original file line number	Diff line number	Diff line change
`@@ -10210,6 +10210,7 @@ static void zend_compile_binary_op(znode result, zend_ast ast) /* {{{ */`
`10210`	`10210`	`}`
`10211`	`10211`
`10212`	`10212`	`do {`
	`10213`	`+ // TODO do not do this for NAN?`
`10213`	`10214`	`if (opcode == ZEND_IS_EQUAL \|\| opcode == ZEND_IS_NOT_EQUAL) {`
`10214`	`10215`	`if (left_node.op_type == IS_CONST) {`
`10215`	`10216`	`if (Z_TYPE(left_node.u.constant) == IS_FALSE) {`