From: Vladimir V. Kisil <V.Kisil@leeds.ac.uk>
Date: Mon, 22 Jun 2020 07:49:00 +0000 (+0200)
Subject: [BUGFIX] Prevent crashes in find_common_factor()
X-Git-Tag: release_1-7-10~3
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=5f7f81ad35a80e12c6a9a2272e3882387732be4f;hp=933965916b34a17fa77c413dbc23699e26eaa9bf

[BUGFIX] Prevent crashes in find_common_factor()

These happened if a non-normalised common factor was equal to zero.

Thanks to Feng Feng for reporting this bug.
---

diff --git a/ginac/normal.cpp b/ginac/normal.cpp
index a80e1508..8e44bee2 100644
--- a/ginac/normal.cpp
+++ b/ginac/normal.cpp
@@ -2565,7 +2565,7 @@ static ex find_common_factor(const ex & e, ex & factor, exmap & repl)
 				x *= f;
 			}
 
-			if (i == 0)
+			if (gc.is_zero())
 				gc = x;
 			else
 				gc = gcd(gc, x);
@@ -2576,6 +2576,9 @@ static ex find_common_factor(const ex & e, ex & factor, exmap & repl)
 		if (gc.is_equal(_ex1))
 			return e;
 
+		if (gc.is_zero())
+			return _ex0;
+
 		// The GCD is the factor we pull out
 		factor *= gc;