internal/lsp: sort rename results

We recommend that gopls integrators apply the []TextEdit responses in
reverse order to get a correct resulting document. This strategy works
when the response is already sorted. Have gopls return sorted []TextEdit
for each file.

Fixes golang/go#33123

Change-Id: Ib570881c9623695d2ae3194fa8a97b0a681a3250
Reviewed-on: https://go-review.googlesource.com/c/tools/+/186258
Run-TryBot: Suzy Mueller <suzmue@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/lsp_test.go

@@ -582,7 +582,6 @@ func (r *runner) Rename(t *testing.T, data tests.Renames) {
 
 func applyEdits(contents string, edits []source.TextEdit) string {
 	res := contents
-	sortSourceTextEdits(edits)
 
 	// Apply the edits from the end of the file forward
 	// to preserve the offsets
@@ -596,15 +595,6 @@ func applyEdits(contents string, edits []source.TextEdit) string {
 	return res
 }
 
-func sortSourceTextEdits(d []source.TextEdit) {
-	sort.Slice(d, func(i int, j int) bool {
-		if r := span.Compare(d[i].Span, d[j].Span); r != 0 {
-			return r < 0
-		}
-		return d[i].NewText < d[j].NewText
-	})
-}
-
 func (r *runner) Symbol(t *testing.T, data tests.Symbols) {
 	for uri, expectedSymbols := range data {
 		params := &protocol.DocumentSymbolParams{

internal/lsp/source/rename.go

@@ -85,7 +85,16 @@ func (i *IdentifierInfo) Rename(ctx context.Context, newName string) (map[span.U
 		return nil, fmt.Errorf(r.errors)
 	}
 
-	return r.update()
+	changes, err := r.update()
+	if err != nil {
+		return nil, err
+	}
+
+	// Sort edits for each file.
+	for _, edits := range changes {
+		sortTextEdits(edits)
+	}
+	return changes, nil
 }
 
 // Rename all references to the identifier.

internal/lsp/source/source_test.go

@@ -547,7 +547,6 @@ func (r *runner) Rename(t *testing.T, data tests.Renames) {
 
 func applyEdits(contents string, edits []source.TextEdit) string {
 	res := contents
-	sortSourceTextEdits(edits)
 
 	// Apply the edits from the end of the file forward
 	// to preserve the offsets
@@ -561,15 +560,6 @@ func applyEdits(contents string, edits []source.TextEdit) string {
 	return res
 }
 
-func sortSourceTextEdits(d []source.TextEdit) {
-	sort.Slice(d, func(i int, j int) bool {
-		if r := span.Compare(d[i].Span, d[j].Span); r != 0 {
-			return r < 0
-		}
-		return d[i].NewText < d[j].NewText
-	})
-}
-
 func (r *runner) Symbol(t *testing.T, data tests.Symbols) {
 	ctx := r.ctx
 	for uri, expectedSymbols := range data {

internal/lsp/source/view.go

@@ -9,6 +9,7 @@ import (
 	"go/ast"
 	"go/token"
 	"go/types"
+	"sort"
 	"strings"
 
 	"golang.org/x/tools/go/analysis"
@@ -318,3 +319,10 @@ func EditsToDiff(edits []TextEdit) []*diff.Op {
 	}
 	return ops
 }
+
+func sortTextEdits(d []TextEdit) {
+	// Use a stable sort to maintain the order of edits inserted at the same position.
+	sort.SliceStable(d, func(i int, j int) bool {
+		return span.Compare(d[i].Span, d[j].Span) < 0
+	})
+}