make bcpowmod stricter by not returning false, instead throw exception

Closes GH-5747

Author: vv12131415

ext/bcmath/bcmath.c

@@ -404,10 +404,16 @@ PHP_FUNCTION(bcpowmod)
 	php_str2num(&second, ZSTR_VAL(right));
 	php_str2num(&mod, ZSTR_VAL(modulus));
 
-	if (bc_raisemod(first, second, mod, &result, scale) != -1) {
-		RETVAL_STR(bc_num2str_ex(result, scale));
-	} else {
-		RETVAL_FALSE;
+	switch (bc_raisemod(first, second, mod, &result, scale)) {
+		case 0:
+			RETVAL_STR(bc_num2str_ex(result, scale));
+			break;
+		case -1:
+			zend_throw_exception_ex(zend_ce_division_by_zero_error, 0, "Modulo by zero");
+			break;
+		case -2:
+			zend_argument_value_error(2, "must be greater than 0");
+			break;
 	}
 
 	bc_free_num(&first);

ext/bcmath/bcmath.stub.php

@@ -12,7 +12,7 @@ function bcdiv(string $dividend, string $divisor, ?int $scale = null): string {}
 
 function bcmod(string $dividend, string $divisor, ?int $scale = null): string {}
 
-function bcpowmod(string $base, string $exponent, string $modulus, ?int $scale = null): string|false {}
+function bcpowmod(string $base, string $exponent, string $modulus, ?int $scale = null): string {}
 
 function bcpow(string $base, string $exponent, ?int $scale = null): string {}
 

ext/bcmath/bcmath_arginfo.h

@@ -18,7 +18,7 @@ ZEND_END_ARG_INFO()
 
 #define arginfo_bcmod arginfo_bcdiv
 
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_bcpowmod, 0, 3, MAY_BE_STRING|MAY_BE_FALSE)
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_bcpowmod, 0, 3, IS_STRING, 0)
 	ZEND_ARG_TYPE_INFO(0, base, IS_STRING, 0)
 	ZEND_ARG_TYPE_INFO(0, exponent, IS_STRING, 0)
 	ZEND_ARG_TYPE_INFO(0, modulus, IS_STRING, 0)

ext/bcmath/libbcmath/src/raisemod.c

@@ -67,7 +67,7 @@ bc_raisemod (bc_num base, bc_num expo, bc_num mod, bc_num *result, int scale)
 
   /* Check for correct numbers. */
   if (bc_is_zero(mod)) return -1;
-  if (bc_is_neg(expo)) return -1;
+  if (bc_is_neg(expo)) return -2;
 
   /* Set initial values.  */
   power = bc_copy_num (base);

ext/bcmath/tests/bcpowmod_negative_exponent.phpt

@@ -0,0 +1,16 @@
+--TEST--
+bc_raisemod's expo can't be negative
+--CREDITS--
+Gabriel Caruso (carusogabriel34@gmail.com)
+--SKIPIF--
+<?php if(!extension_loaded('bcmath')) die('skip bcmath extension not loaded'); ?>
+--FILE--
+<?php
+try {
+    var_dump(bcpowmod('1', '-1', '2'));
+} catch (\ValueError $e) {
+    echo $e->getMessage() . \PHP_EOL;
+}
+?>
+--EXPECT--
+bcpowmod(): Argument #2 ($exponent) must be greater than 0

ext/bcmath/tests/bcpowmod_error4.phpt renamed to ext/bcmath/tests/bcpowmod_zero_modulus.phpt

@@ -1,10 +1,16 @@
 --TEST--
-bc_raisemod's mod can't be zero and expo can't be negative
+bc_raisemod's mod can't be zero
 --CREDITS--
 Gabriel Caruso (carusogabriel34@gmail.com)
 --SKIPIF--
 <?php if(!extension_loaded('bcmath')) die('skip bcmath extension not loaded'); ?>
 --FILE--
-<?php var_dump(bcpowmod('1', '-1', '0')); ?>
+<?php
+try {
+    var_dump(bcpowmod('1', '-1', '0'));
+} catch (DivisionByZeroError $ex) {
+    echo $ex->getMessage(), PHP_EOL;
+}
+?>
 --EXPECT--
-bool(false)
+Modulo by zero

ext/opcache/Optimizer/zend_func_info.c

@@ -789,7 +789,7 @@ static const func_info_t func_infos[] = {
 	F1("bcmul",									MAY_BE_STRING),
 	F1("bcdiv",									MAY_BE_STRING),
 	F1("bcmod",									MAY_BE_STRING),
-	F1("bcpowmod",								MAY_BE_FALSE | MAY_BE_STRING),
+	F1("bcpowmod",								MAY_BE_STRING),
 	F1("bcpow",									MAY_BE_STRING),
 	F1("bcsqrt",								MAY_BE_STRING),