Fix a rounding bug in display of data sizes

Eg, showImprecise 1 1.99 returned "1.1" rather than "2". The 9 rounded
upward to 10, and that was wrongly used as the decimal, rather than
carrying the 1.

Sponsored-by: Jack Hill on Patreon

Utility/HumanNumber.hs

@@ -1,6 +1,6 @@
 {- numbers for humans
  -
- - Copyright 2012-2013 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2021 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
@@ -11,11 +11,15 @@ module Utility.HumanNumber (showImprecise) where
  - of decimal digits. -}
 showImprecise :: RealFrac a => Int -> a -> String
 showImprecise precision n
-	| precision == 0 || remainder == 0 = show (round n :: Integer)
-	| otherwise = show int ++ "." ++ striptrailing0s (pad0s $ show remainder)
+	| precision == 0 || remainder' == 0 = show (round n :: Integer)
+	| otherwise = show int' ++ "." ++ striptrailing0s (pad0s $ show remainder')
   where
 	int :: Integer
 	(int, frac) = properFraction n
 	remainder = round (frac * 10 ^ precision) :: Integer
+	(int', remainder')
+		-- carry the 1
+		| remainder == 10 ^ precision = (int + 1, 0)
+		| otherwise = (int, remainder)
 	pad0s s = replicate (precision - length s) '0' ++ s
 	striptrailing0s = reverse . dropWhile (== '0') . reverse