internal/lsp: do not allow diff.ApplyEdits to be replaced

We only need one implementation of this, it must cope with all inputs, and it
has no freedom in it's results, so it does not need to be pluggable.

Change-Id: I6fec0c339eb288649a670fc3e2cb00c726467e20
Reviewed-on: https://go-review.googlesource.com/c/tools/+/198377
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/diff/apply_edits.go

@@ -7,11 +7,7 @@ import (
 	"golang.org/x/tools/internal/span"
 )
 
-func init() {
-	ApplyEdits = applyEdits
-}
-
-func applyEdits(before string, edits []TextEdit) string {
+func ApplyEdits(before string, edits []TextEdit) string {
 	// Preconditions:
 	//   - all of the edits apply to before
 	//   - and all the spans for each TextEdit have the same URI

internal/lsp/diff/apply_edits_test.go

@@ -1,24 +1,25 @@
-package diff
+package diff_test
 
 import (
 	"testing"
 
+	"golang.org/x/tools/internal/lsp/diff"
 	"golang.org/x/tools/internal/span"
 )
 
 func TestApplyEdits(t *testing.T) {
 	var testCases = []struct {
 		before string
-		edits  []TextEdit
+		edits  []diff.TextEdit
 		want   string
 	}{
 		{"", nil, ""},
-		{"X", []TextEdit{{newSpan(0, 1), "Y"}}, "Y"},
-		{" X ", []TextEdit{{newSpan(1, 2), "Y"}}, " Y "},
-		{" X X ", []TextEdit{{newSpan(1, 2), "Y"}, {newSpan(3, 4), "Z"}}, " Y Z "},
+		{"X", []diff.TextEdit{{newSpan(0, 1), "Y"}}, "Y"},
+		{" X ", []diff.TextEdit{{newSpan(1, 2), "Y"}}, " Y "},
+		{" X X ", []diff.TextEdit{{newSpan(1, 2), "Y"}, {newSpan(3, 4), "Z"}}, " Y Z "},
 	}
 	for _, tc := range testCases {
-		if got := applyEdits(tc.before, tc.edits); got != tc.want {
+		if got := diff.ApplyEdits(tc.before, tc.edits); got != tc.want {
 			t.Errorf("applyEdits(%v, %v): got %v, want %v", tc.before, tc.edits, got, tc.want)
 		}
 	}

internal/lsp/diff/hooks.go

@@ -20,7 +20,6 @@ type TextEdit struct {
 
 var (
 	ComputeEdits func(uri span.URI, before, after string) []TextEdit
-	ApplyEdits   func(before string, edits []TextEdit) string
 	ToUnified    func(from, to string, before string, edits []TextEdit) string
 )