Bug #9989: Docs give wrong information for sort block return values

• Status: Closed
• Assignee: zzak (zzak _)
• Target version: 2.2.0
• ruby -v: 2.1.2
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN

[robyoder (Rob Yoder)]

Under the Array.sort documentation, this statement is made:

Comparisons for the sort will be done using the <=> operator or using an optional code block.

The block must implement a comparison between a and b, and return -1, when a follows b, 0 when a and b are equivalent, or +1 if b follows a.

This is incorrect. The default sort block is { |a,b| a <=> b }. That is ascending sort, where 2 would follow 1. However, 1 <=> 2 returns -1, not +1 as the statement claims. The statement should read:

The block must implement a comparison between a and b, and return -1 when b follows a, 0 when a and b are equivalent, or +1 if a follows b.

[robyoder (Rob Yoder)]

This occurs under Array.sort and Array.sort! (http://www.ruby-doc.org/core-2.1.2/Array.html#method-i-sort)

Enumerable.sort vaguely states:

The block should return -1, 0, or +1 depending on the comparison between a and b.

(http://ruby-doc.org/core-2.1.2/Enumerable.html#method-i-sort)

[ayumin (Ayumu AIZAWA)]

• Related to Bug #10125: Array#sort and #sort! documentation issue added

[stomar (Marcus Stollsteimer)]

• Status changed from Open to Closed

Fixed with r51859 (Array) and r57770 (Enumerable).