From a995269a9383d90a3bdd029989bafc8fc3b19dc3 Mon Sep 17 00:00:00 2001 From: John Giorshev Date: Sun, 6 Jul 2025 18:41:28 +0000 Subject: [PATCH] sort: clarify Less doc clarifies the requirements for Less Fixes https://github.com/golang/go/issues/73420 Change-Id: I7d49b10fad78c618d946b3bb161ce19680ede47a GitHub-Last-Rev: 7a49ad81923048bfc99b265dd89f012eefcf5699 GitHub-Pull-Request: golang/go#74333 Reviewed-on: https://go-review.googlesource.com/c/go/+/683275 Reviewed-by: Keith Randall Reviewed-by: Keith Randall Auto-Submit: Keith Randall Reviewed-by: Carlos Amedee LUCI-TryBot-Result: Go LUCI --- src/sort/sort.go | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/sort/sort.go b/src/sort/sort.go index b27ecabdd5..fd3cd6dabf 100644 --- a/src/sort/sort.go +++ b/src/sort/sort.go @@ -26,13 +26,15 @@ type Interface interface { // Sort may place equal elements in any order in the final result, // while Stable preserves the original input order of equal elements. // - // Less must describe a transitive ordering: + // Less must describe a [Strict Weak Ordering]. For example: // - if both Less(i, j) and Less(j, k) are true, then Less(i, k) must be true as well. // - if both Less(i, j) and Less(j, k) are false, then Less(i, k) must be false as well. // // Note that floating-point comparison (the < operator on float32 or float64 values) - // is not a transitive ordering when not-a-number (NaN) values are involved. + // is not a strict weak ordering when not-a-number (NaN) values are involved. // See Float64Slice.Less for a correct implementation for floating-point values. + // + // [Strict Weak Ordering]: https://en.wikipedia.org/wiki/Weak_ordering#Strict_weak_orderings Less(i, j int) bool // Swap swaps the elements with indexes i and j. -- 2.50.0