Stabilizing go/scanner.(*ErrorList).Sort

[Jan Mercl]

I'm getting diffs from some tests like this:

        -testdata/foo.go:19:44: "bar"

         testdata/foo.go:19:44: "qux"

        +testdata/foo.go:19:44: "bar"

This is because (*ErrorList).Less does not consider the Msg field.

I'd like to propose to consider the Msg field iff all other properties of the compared items a, b compare as !(a < b).

AFAICS, the change is backward compatible and should not break existing code. If approved, I'm happy to submit a CL; provided the Go team does not prefer otherwise.

-j

[Jan Mercl]

On Tue, Mar 31, 2015 at 10:06 AM Jan Mercl <0xj...@gmail.com> wrote:

> iff all other properties of the compared items a, b compare as !(a < b).

s/!(a < b)/equal/

ie. this seems to work for me

diff --git a/src/go/scanner/errors.go b/src/go/scanner/errors.go

index 22de69c..7c9ab25 100644

--- a/src/go/scanner/errors.go

+++ b/src/go/scanner/errors.go

@@ -62,7 +62,14 @@ func (p ErrorList) Less(i, j int) bool {

                        return true

                }

                if e.Line == f.Line {

-                       return e.Column < f.Column

+                       if e.Column < f.Column {

+                               return true

+                       }

+                       if e.Column == f.Column {

+                               if p[i].Msg < p[j].Msg {

+                                       return true

+                               }

+                       }

                }

        }

        return false

-j

[David Symonds]

It seems reasonable to me. Send a CL to gri.