go/doc: document rationale for recent change

LGTM=adg
R=adg
CC=golang-codereviews
https://golang.org/cl/143290043

diff --git a/src/go/doc/exports.go b/src/go/doc/exports.go
index 9b421e73412606e1926d7af67fc5587125e8c04f..1d3b466d8c7bb6d767913f04ec8843470ab3713b 100644 (file)
--- a/src/go/doc/exports.go
+++ b/src/go/doc/exports.go
@@ -12,7 +12,8 @@ import (
 )
 
 // filterIdentList removes unexported names from list in place
-// and returns the resulting list.
+// and returns the resulting list. If blankOk is set, blank
+// identifiers are considered exported names.
 //
 func filterIdentList(list []*ast.Ident, blankOk bool) []*ast.Ident {
        j := 0
@@ -145,6 +146,8 @@ func (r *reader) filterSpec(spec ast.Spec, tok token.Token) bool {
                // always keep imports so we can collect them
                return true
        case *ast.ValueSpec:
+               // special case: consider blank constants as exported
+               // (work-around for issue 5397)
                s.Names = filterIdentList(s.Names, tok == token.CONST)
                if len(s.Names) > 0 {
                        r.filterType(nil, s.Type)