From 427c84f13f7719e6014a21bd1b81efdc02a046fb Mon Sep 17 00:00:00 2001
From: Sebastian Berg <sebastian@sipsolutions.net>
Date: Thu, 6 Feb 2020 06:54:05 -0800
Subject: bpo-39274: Ensure Fraction.__bool__() returns a bool (GH-18017)

Some numerator types used (specifically NumPy) decides to not
return a Python boolean for the "a != b" operation. Using the equivalent
call to bool() guarantees a bool return also for such types.
---
 Lib/fractions.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'Lib/fractions.py')

diff --git a/Lib/fractions.py b/Lib/fractions.py
index 501f4b74a0..f5a854414c 100644
--- a/Lib/fractions.py
+++ b/Lib/fractions.py
@@ -625,7 +625,9 @@ class Fraction(numbers.Rational):
 
     def __bool__(a):
         """a != 0"""
-        return a._numerator != 0
+        # bpo-39274: Use bool() because (a._numerator != 0) can return an
+        # object which is not a bool.
+        return bool(a._numerator)
 
     # support for pickling, copy, and deepcopy
 
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