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PHP 7.4 Warning for string to number comparisons that may change #3917

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148d797
Print warning if comparison result will change
nikic Mar 4, 2019
b2350cc
Don't throw a warning for 1/-1 flips on equality comparisons
nikic Mar 4, 2019
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170 changes: 160 additions & 10 deletions Zend/zend_operators.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2019,7 +2019,96 @@ static void ZEND_FASTCALL convert_compare_result_to_long(zval *result) /* {{{ */
}
/* }}} */

ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2) /* {{{ */
static int compare_long_to_string(zend_long lval, zend_string *str, zend_bool equality_only) /* {{{ */
{
zend_long str_lval;
double str_dval;
int num_cmp_result;
zend_uchar type = is_numeric_string(ZSTR_VAL(str), ZSTR_LEN(str), &str_lval, &str_dval, 1);

if (type == IS_LONG) {
num_cmp_result = lval > str_lval ? 1 : lval < str_lval ? -1 : 0;
} else if (type == IS_DOUBLE) {
double diff = (double) lval - str_dval;
num_cmp_result = ZEND_NORMALIZE_BOOL(diff);
} else {
num_cmp_result = ZEND_NORMALIZE_BOOL(lval);
}

/* TODO Avoid duplicate is_numeric_string call. */
zend_bool is_numeric = is_numeric_string(ZSTR_VAL(str), ZSTR_LEN(str), &str_lval, &str_dval, 0);
if (is_numeric) {
/* For numeric strings, the comparison result stays the same. */
return num_cmp_result;
}

zend_string *lval_as_str = zend_long_to_str(lval);
int str_cmp_result = zend_binary_strcmp(
ZSTR_VAL(lval_as_str), ZSTR_LEN(lval_as_str), ZSTR_VAL(str), ZSTR_LEN(str));
str_cmp_result = ZEND_NORMALIZE_BOOL(str_cmp_result);
zend_string_release(lval_as_str);

/* Don't report a warning if we're using == and the comparison changed between 1/-1. */
zend_bool cmp_result_changed_observably = str_cmp_result != num_cmp_result &&
(!equality_only || str_cmp_result == 0 || num_cmp_result == 0);
if (cmp_result_changed_observably) {
zend_error(E_WARNING,
"Result of comparison between " ZEND_LONG_FMT " and \"%s\" will change (%d to %d)",
lval, ZSTR_VAL(str), num_cmp_result, str_cmp_result);
}

/* Return old (numeric) comparison result. */
return num_cmp_result;
}
/* }}} */

static int compare_double_to_string(double dval, zend_string *str, zend_bool equality_only) /* {{{ */
{
zend_long str_lval;
double str_dval;
int num_cmp_result;
zend_uchar type = is_numeric_string(ZSTR_VAL(str), ZSTR_LEN(str), &str_lval, &str_dval, 0);

if (type == IS_LONG) {
double diff = dval - (double) str_lval;
num_cmp_result = ZEND_NORMALIZE_BOOL(diff);
} else if (type == IS_DOUBLE) {
if (dval == str_dval) {
return 0;
}
num_cmp_result = ZEND_NORMALIZE_BOOL(dval - str_dval);
} else {
num_cmp_result = ZEND_NORMALIZE_BOOL(dval);
}

/* TODO Avoid duplicate is_numeric_string call. */
zend_bool is_numeric = is_numeric_string(ZSTR_VAL(str), ZSTR_LEN(str), &str_lval, &str_dval, 0);
if (is_numeric) {
/* For numeric strings, the comparison result stays the same. */
return num_cmp_result;
}

zend_string *dval_as_str = zend_strpprintf(0, "%.*G", (int) EG(precision), dval);
int str_cmp_result = zend_binary_strcmp(
ZSTR_VAL(dval_as_str), ZSTR_LEN(dval_as_str), ZSTR_VAL(str), ZSTR_LEN(str));
str_cmp_result = ZEND_NORMALIZE_BOOL(str_cmp_result);
zend_string_release(dval_as_str);

/* Don't report a warning if we're using == and the comparison changed between 1/-1. */
zend_bool cmp_result_changed_observably = str_cmp_result != num_cmp_result &&
(!equality_only || str_cmp_result == 0 || num_cmp_result == 0);
if (cmp_result_changed_observably) {
zend_error(E_WARNING,
"Result of comparison between %G and \"%s\" will change (%d to %d)",
dval, ZSTR_VAL(str), num_cmp_result, str_cmp_result);
}

/* Return old (numeric) comparison result. */
return num_cmp_result;
}
/* }}} */

ZEND_API int ZEND_FASTCALL compare_function_ex(zval *result, zval *op1, zval *op2, zend_bool equality_only) /* {{{ */
{
int ret;
int converted = 0;
Expand Down Expand Up @@ -2052,7 +2141,7 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
return SUCCESS;

case TYPE_PAIR(IS_ARRAY, IS_ARRAY):
ZVAL_LONG(result, zend_compare_arrays(op1, op2));
ZVAL_LONG(result, zend_compare_arrays_ex(op1, op2, equality_only));
return SUCCESS;

case TYPE_PAIR(IS_NULL, IS_NULL):
Expand Down Expand Up @@ -2087,6 +2176,32 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
ZVAL_LONG(result, Z_STRLEN_P(op1) == 0 ? 0 : 1);
return SUCCESS;

case TYPE_PAIR(IS_LONG, IS_STRING):
ZVAL_LONG(result, compare_long_to_string(Z_LVAL_P(op1), Z_STR_P(op2), equality_only));
return SUCCESS;

case TYPE_PAIR(IS_STRING, IS_LONG):
ZVAL_LONG(result, -compare_long_to_string(Z_LVAL_P(op2), Z_STR_P(op1), equality_only));
return SUCCESS;

case TYPE_PAIR(IS_DOUBLE, IS_STRING):
if (zend_isnan(Z_DVAL_P(op1))) {
ZVAL_LONG(result, 1);
return SUCCESS;
}

ZVAL_LONG(result, compare_double_to_string(Z_DVAL_P(op1), Z_STR_P(op2), equality_only));
return SUCCESS;

case TYPE_PAIR(IS_STRING, IS_DOUBLE):
if (zend_isnan(Z_DVAL_P(op2))) {
ZVAL_LONG(result, 1);
return SUCCESS;
}

ZVAL_LONG(result, -compare_double_to_string(Z_DVAL_P(op2), Z_STR_P(op1), equality_only));
return SUCCESS;

case TYPE_PAIR(IS_OBJECT, IS_NULL):
ZVAL_LONG(result, 1);
return SUCCESS;
Expand Down Expand Up @@ -2133,7 +2248,7 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
if (Z_OBJ_HT_P(op1)->get) {
zval rv;
op_free = Z_OBJ_HT_P(op1)->get(op1, &rv);
ret = compare_function(result, op_free, op2);
ret = compare_function_ex(result, op_free, op2, equality_only);
zend_free_obj_get_result(op_free);
return ret;
} else if (Z_TYPE_P(op2) != IS_OBJECT && Z_OBJ_HT_P(op1)->cast_object) {
Expand All @@ -2143,7 +2258,7 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
zend_free_obj_get_result(&tmp_free);
return SUCCESS;
}
ret = compare_function(result, &tmp_free, op2);
ret = compare_function_ex(result, &tmp_free, op2, equality_only);
zend_free_obj_get_result(&tmp_free);
return ret;
}
Expand All @@ -2152,7 +2267,7 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
if (Z_OBJ_HT_P(op2)->get) {
zval rv;
op_free = Z_OBJ_HT_P(op2)->get(op2, &rv);
ret = compare_function(result, op1, op_free);
ret = compare_function_ex(result, op1, op_free, equality_only);
zend_free_obj_get_result(op_free);
return ret;
} else if (Z_TYPE_P(op1) != IS_OBJECT && Z_OBJ_HT_P(op2)->cast_object) {
Expand All @@ -2162,7 +2277,7 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
zend_free_obj_get_result(&tmp_free);
return SUCCESS;
}
ret = compare_function(result, op1, &tmp_free);
ret = compare_function_ex(result, op1, &tmp_free, equality_only);
zend_free_obj_get_result(&tmp_free);
return ret;
} else if (Z_TYPE_P(op1) == IS_OBJECT) {
Expand Down Expand Up @@ -2213,6 +2328,12 @@ ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2)
}
/* }}} */

ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2) /* {{{ */
{
return compare_function_ex(result, op1, op2, 0);
}
/* }}} */

static int hash_zval_identical_function(zval *z1, zval *z2) /* {{{ */
{
/* is_identical_function() returns 1 in case of identity and 0 in case
Expand Down Expand Up @@ -2271,7 +2392,7 @@ ZEND_API int ZEND_FASTCALL is_not_identical_function(zval *result, zval *op1, zv

ZEND_API int ZEND_FASTCALL is_equal_function(zval *result, zval *op1, zval *op2) /* {{{ */
{
if (compare_function(result, op1, op2) == FAILURE) {
if (compare_function_ex(result, op1, op2, 1) == FAILURE) {
return FAILURE;
}
ZVAL_BOOL(result, (Z_LVAL_P(result) == 0));
Expand All @@ -2281,7 +2402,7 @@ ZEND_API int ZEND_FASTCALL is_equal_function(zval *result, zval *op1, zval *op2)

ZEND_API int ZEND_FASTCALL is_not_equal_function(zval *result, zval *op1, zval *op2) /* {{{ */
{
if (compare_function(result, op1, op2) == FAILURE) {
if (compare_function_ex(result, op1, op2, 1) == FAILURE) {
return FAILURE;
}
ZVAL_BOOL(result, (Z_LVAL_P(result) != 0));
Expand Down Expand Up @@ -2967,15 +3088,44 @@ static int hash_zval_compare_function(zval *z1, zval *z2) /* {{{ */
}
/* }}} */

static int hash_zval_compare_function_equality(zval *z1, zval *z2) /* {{{ */
{
zval result;

if (compare_function_ex(&result, z1, z2, 1)==FAILURE) {
return 1;
}
return Z_LVAL(result);
}
/* }}} */

ZEND_API int ZEND_FASTCALL zend_compare_symbol_tables_ex(HashTable *ht1, HashTable *ht2, zend_bool equality_only) /* {{{ */
{
if (ht1 == ht2) {
return 0;
}
return zend_hash_compare(ht1, ht2,
equality_only
? (compare_func_t) hash_zval_compare_function_equality
: (compare_func_t) hash_zval_compare_function, 0);
}
/* }}} */

ZEND_API int ZEND_FASTCALL zend_compare_symbol_tables(HashTable *ht1, HashTable *ht2) /* {{{ */
{
return ht1 == ht2 ? 0 : zend_hash_compare(ht1, ht2, (compare_func_t) hash_zval_compare_function, 0);
return zend_compare_symbol_tables_ex(ht1, ht2, 0);
}
/* }}} */

ZEND_API int ZEND_FASTCALL zend_compare_arrays_ex(zval *a1, zval *a2, zend_bool equality_only) /* {{{ */
{
return zend_compare_symbol_tables_ex(Z_ARRVAL_P(a1), Z_ARRVAL_P(a2), equality_only);
}
/* }}} */

ZEND_API int ZEND_FASTCALL zend_compare_arrays(zval *a1, zval *a2) /* {{{ */
{
return zend_compare_symbol_tables(Z_ARRVAL_P(a1), Z_ARRVAL_P(a2));
return zend_compare_symbol_tables_ex(Z_ARRVAL_P(a1), Z_ARRVAL_P(a2), 0);
}
/* }}} */

Expand Down
9 changes: 6 additions & 3 deletions Zend/zend_operators.h
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Original file line number Diff line number Diff line change
Expand Up @@ -388,6 +388,7 @@ static zend_always_inline int i_zend_is_true(zval *op)
return result;
}

ZEND_API int ZEND_FASTCALL compare_function_ex(zval *result, zval *op1, zval *op2, zend_bool equality_only);
ZEND_API int ZEND_FASTCALL compare_function(zval *result, zval *op1, zval *op2);

ZEND_API int ZEND_FASTCALL numeric_compare_function(zval *op1, zval *op2);
Expand Down Expand Up @@ -417,7 +418,9 @@ ZEND_API int ZEND_FASTCALL zend_binary_strncasecmp_l(const char *s1, size_t len1

ZEND_API int ZEND_FASTCALL zendi_smart_streq(zend_string *s1, zend_string *s2);
ZEND_API int ZEND_FASTCALL zendi_smart_strcmp(zend_string *s1, zend_string *s2);
ZEND_API int ZEND_FASTCALL zend_compare_symbol_tables_ex(HashTable *ht1, HashTable *ht2, zend_bool equality_only);
ZEND_API int ZEND_FASTCALL zend_compare_symbol_tables(HashTable *ht1, HashTable *ht2);
ZEND_API int ZEND_FASTCALL zend_compare_arrays_ex(zval *a1, zval *a2, zend_bool equality_only);
ZEND_API int ZEND_FASTCALL zend_compare_arrays(zval *a1, zval *a2);
ZEND_API int ZEND_FASTCALL zend_compare_objects(zval *o1, zval *o2);

Expand Down Expand Up @@ -860,7 +863,7 @@ static zend_always_inline int fast_equal_check_function(zval *op1, zval *op2)
return zend_fast_equal_strings(Z_STR_P(op1), Z_STR_P(op2));
}
}
compare_function(&result, op1, op2);
compare_function_ex(&result, op1, op2, 1);
return Z_LVAL(result) == 0;
}

Expand All @@ -870,7 +873,7 @@ static zend_always_inline int fast_equal_check_long(zval *op1, zval *op2)
if (EXPECTED(Z_TYPE_P(op2) == IS_LONG)) {
return Z_LVAL_P(op1) == Z_LVAL_P(op2);
}
compare_function(&result, op1, op2);
compare_function_ex(&result, op1, op2, 1);
return Z_LVAL(result) == 0;
}

Expand All @@ -880,7 +883,7 @@ static zend_always_inline int fast_equal_check_string(zval *op1, zval *op2)
if (EXPECTED(Z_TYPE_P(op2) == IS_STRING)) {
return zend_fast_equal_strings(Z_STR_P(op1), Z_STR_P(op2));
}
compare_function(&result, op1, op2);
compare_function_ex(&result, op1, op2, 1);
return Z_LVAL(result) == 0;
}

Expand Down
8 changes: 4 additions & 4 deletions Zend/zend_vm_def.h
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Original file line number Diff line number Diff line change
Expand Up @@ -498,7 +498,7 @@ ZEND_VM_HELPER(zend_is_equal_helper, ANY, ANY, zval *op_1, zval *op_2)
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (OP1_TYPE & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down Expand Up @@ -593,7 +593,7 @@ ZEND_VM_HELPER(zend_is_not_equal_helper, ANY, ANY, zval *op_1, zval *op_2)
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (OP1_TYPE & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down Expand Up @@ -688,7 +688,7 @@ ZEND_VM_HELPER(zend_is_smaller_helper, ANY, ANY, zval *op_1, zval *op_2)
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (OP1_TYPE & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down Expand Up @@ -768,7 +768,7 @@ ZEND_VM_HELPER(zend_is_smaller_or_equal_helper, ANY, ANY, zval *op_1, zval *op_2
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (OP1_TYPE & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down
8 changes: 4 additions & 4 deletions Zend/zend_vm_execute.h
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Original file line number Diff line number Diff line change
Expand Up @@ -587,7 +587,7 @@ static zend_never_inline ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_is_equal_hel
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (opline->op1_type & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down Expand Up @@ -619,7 +619,7 @@ static zend_never_inline ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_is_not_equal
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (opline->op1_type & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down Expand Up @@ -651,7 +651,7 @@ static zend_never_inline ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_is_smaller_h
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (opline->op1_type & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down Expand Up @@ -683,7 +683,7 @@ static zend_never_inline ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_is_smaller_o
if (UNEXPECTED(Z_TYPE_INFO_P(op_2) == IS_UNDEF)) {
op_2 = ZVAL_UNDEFINED_OP2();
}
compare_function(EX_VAR(opline->result.var), op_1, op_2);
compare_function_ex(EX_VAR(opline->result.var), op_1, op_2, 1);
if (opline->op1_type & (IS_TMP_VAR|IS_VAR)) {
zval_ptr_dtor_nogc(op_1);
}
Expand Down