Bugfix#70896 gmp_fact() silently ignores non-integer inputs

Factorials only make sense for integer inputs.
To do something factorial-like, the Gamma Function
should be used instead.
However, at this point it's no longer a factorial.

For PHP/GMP, we'll raise a warning on trying to use
a non-integer input, but carry on returning the truncated
value as we used to (avoiding BC breakage).

NEWS

@@ -2,4 +2,7 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? 2016, PHP 7.2.0alpha1
 
+- GMP:
+  . Fixed bug #70896 (gmp_fact() silently ignores non-integer input). (Sara)
+
 <<< NOTE: Insert NEWS from last stable release here prior to actual release! >>>

ext/gmp/gmp.c

@@ -1365,7 +1365,16 @@ ZEND_FUNCTION(gmp_fact)
 			RETURN_FALSE;
 		}
 	} else {
-		if (zval_get_long(a_arg) < 0) {
+		/* Use convert_to_number first to detect getting non-integer */
+		convert_scalar_to_number(a_arg);
+		if (Z_TYPE_P(a_arg) != IS_LONG) {
+			convert_to_long(a_arg);
+			if (Z_LVAL_P(a_arg) >= 0) {
+				/* Only warn if we'll make it past the non-negative check */
+				php_error_docref(NULL, E_WARNING, "Number has to be an integer");
+			}
+		}
+		if (Z_LVAL_P(a_arg) < 0) {
 			php_error_docref(NULL, E_WARNING, "Number has to be greater than or equal to 0");
 			RETURN_FALSE;
 		}

ext/gmp/tests/gmp_fact.phpt

@@ -38,6 +38,8 @@ string(1) "0"
 
 Warning: gmp_fact(): Number has to be greater than or equal to 0 in %s on line %d
 string(1) "0"
+
+Warning: gmp_fact(): Number has to be an integer in %s on line %d
 string(1) "1"
 string(19) "2432902008176640000"
 string(65) "30414093201713378043612608166064768844377641568960512000000000000"
@@ -53,9 +55,13 @@ NULL
 
 Warning: gmp_fact() expects exactly 1 parameter, 2 given in %s on line %d
 NULL
+
+Warning: gmp_fact(): Number has to be an integer in %s on line %d
 object(GMP)#%d (1) {
   ["num"]=>
   string(1) "1"
 }
+
+Warning: gmp_fact(): Number has to be an integer in %s on line %d
 string(1) "1"
 Done