Fix a performance issue in Decimal.pow. Thanks Stefan Krah for finding this.
diff --git a/Lib/decimal.py b/Lib/decimal.py
index 828027c..71408a8 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -2047,12 +2047,14 @@
# case where xc == 1: result is 10**(xe*y), with xe*y
# required to be an integer
if xc == 1:
- if ye >= 0:
- exponent = xe*yc*10**ye
- else:
- exponent, remainder = divmod(xe*yc, 10**-ye)
- if remainder:
- return None
+ xe *= yc
+ # result is now 10**(xe * 10**ye); xe * 10**ye must be integral
+ while xe % 10 == 0:
+ xe //= 10
+ ye += 1
+ if ye < 0:
+ return None
+ exponent = xe * 10**ye
if y.sign == 1:
exponent = -exponent
# if other is a nonnegative integer, use ideal exponent