pythoncapi
diff --git a/‎Misc/NEWS‎
Lines changed: 3 additions & 0 deletions b/‎Misc/NEWS‎
Lines changed: 3 additions & 0 deletions
diff --git a/‎Objects/longobject.c‎
Lines changed: 2 additions & 1 deletion b/‎Objects/longobject.c‎
Lines changed: 2 additions & 1 deletion
@@ -10,6 +10,9 @@ What's New in Python 3.6.0 beta 1
 Core and Builtins
 -----------------
 
+- Issue #25221: Fix corrupted result from PyLong_FromLong(0) when Python
+  is compiled with NSMALLPOSINTS = 0.
+
 - Issue #27080: Implement formatting support for PEP 515.  Initial patch
   by Chris Angelico.
 
 
@@ -234,7 +234,7 @@ PyLong_FromLong(long ival)
     unsigned long abs_ival;
     unsigned long t;  /* unsigned so >> doesn't propagate sign bit */
     int ndigits = 0;
-    int sign = 1;
+    int sign;
 
     CHECK_SMALL_INT(ival);
 
@@ -246,6 +246,7 @@ PyLong_FromLong(long ival)
     }
     else {
         abs_ival = (unsigned long)ival;
+        sign = ival == 0 ? 0 : 1;
     }
 
     /* Fast path for single-digit ints */
Original file line number	Diff line number	Diff line change
`@@ -234,7 +234,7 @@ PyLong_FromLong(long ival)`
`234`	`234`	`unsigned long abs_ival;`
`235`	`235`	`unsigned long t; /* unsigned so >> doesn't propagate sign bit */`
`236`	`236`	`int ndigits = 0;`
`237`		`- int sign = 1;`
	`237`	`+ int sign;`
`238`	`238`
`239`	`239`	`CHECK_SMALL_INT(ival);`
`240`	`240`
`@@ -246,6 +246,7 @@ PyLong_FromLong(long ival)`
`246`	`246`	`}`
`247`	`247`	`else {`
`248`	`248`	`abs_ival = (unsigned long)ival;`
	`249`	`+ sign = ival == 0 ? 0 : 1;`
`249`	`250`	`}`
`250`	`251`
`251`	`252`	`/* Fast path for single-digit ints */`