cmd/shfmt: swap out pkg/diff for internal/diff

This means one less module dependency, which is a small win.
internal/diff does not handle colors, but it is twenty lines to do,
so it's not worth adding or keeping a dependency just for that.

cmd/shfmt/main.go

@@ -18,8 +18,7 @@ import (
  "strings"
 
  maybeio "github.com/google/renameio/v2/maybe"
- diffpkg "github.com/pkg/diff"
- diffwrite "github.com/pkg/diff/write"
+ diffpkg "github.com/rogpeppe/go-internal/diff"
  "golang.org/x/term"
  "mvdan.cc/editorconfig"
 
@@ -504,12 +503,32 @@ func formatBytes(src []byte, path string, fileLang syntax.LangVariant) error {
  }
  }
  if diff.val {
- opts := []diffwrite.Option{}
- if color {
- opts = append(opts, diffwrite.TerminalColor())
+ diffBytes := diffpkg.Diff(path+".orig", src, path, res)
+ if !color {
+ os.Stdout.Write(diffBytes)
+ return errChangedWithDiff
  }
- if err := diffpkg.Text(path+".orig", path, src, res, os.Stdout, opts...); err != nil {
- return fmt.Errorf("computing diff: %s", err)
+ // The first three lines are the header with the filenames, including --- and +++,
+ // and are marked in bold.
+ current := terminalBold
+ os.Stdout.WriteString(current)
+ for i, line := range bytes.SplitAfter(diffBytes, []byte("\n")) {
+ last := current
+ switch {
+ case i < 3: // the first three lines are bold
+ case bytes.HasPrefix(line, []byte("@@")):
+ current = terminalCyan
+ case bytes.HasPrefix(line, []byte("-")):
+ current = terminalRed
+ case bytes.HasPrefix(line, []byte("+")):
+ current = terminalGreen
+ default:
+ current = terminalReset
+ }
+ if current != last {
+ os.Stdout.WriteString(current)
+ }
+ os.Stdout.Write(line)
  }
  return errChangedWithDiff
  }
@@ -519,3 +538,11 @@ func formatBytes(src []byte, path string, fileLang syntax.LangVariant) error {
  }
  return nil
 }
+
+const (
+ terminalGreen = "\u001b[32m"
+ terminalRed = "\u001b[31m"
+ terminalCyan = "\u001b[36m"
+ terminalReset = "\u001b[0m"
+ terminalBold = "\u001b[1m"
+)

cmd/shfmt/testdata/script/diff.txtar

@@ -13,7 +13,7 @@ cmp stdout input.sh.filediff
 ! stderr .
 
 ! exec shfmt -d input.sh input.sh
-stdout -count=2 'input.sh.orig'
+stdout -count=4 'input.sh.orig'
 
 env FORCE_COLOR=true
 stdin input.sh
@@ -36,20 +36,22 @@ foo
 
 bar
 -- input.sh.stdindiff --
+diff <standard input>.orig <standard input>
 --- <standard input>.orig
 +++ <standard input>
 @@ -1,4 +1,3 @@
 - foo
+-
 +foo
 
--
  bar
 -- input.sh.filediff --
+diff input.sh.orig input.sh
 --- input.sh.orig
 +++ input.sh
 @@ -1,4 +1,3 @@
 - foo
+-
 +foo
 
--
  bar

cmd/shfmt/testdata/script/editorconfig.txtar

@@ -64,8 +64,8 @@ stdout -count=1 'input\.sh$'
 stdout -count=1 'ignored\.sh$'
 stderr -count=1 'ignored\.sh.* must be followed by'
 ! exec shfmt -d input.sh ignored/1_lone_ignored.sh ignored/third_party/bad_syntax_ignored.sh
-stdout -count=1 'input\.sh$'
-stdout -count=1 'ignored\.sh$'
+stdout -count=2 'input\.sh$'
+stdout -count=2 'ignored\.sh$'
 stderr -count=1 'ignored\.sh.* must be followed by'
 ! exec shfmt input.sh ignored/1_lone_ignored.sh ignored/third_party/bad_syntax_ignored.sh
 stdout -count=1 'indented'
@@ -83,7 +83,7 @@ stdout -count=1 'input\.sh$'
 ! stdout 'ignored\.sh'
 ! stderr .
 ! exec shfmt --apply-ignore -d input.sh ignored/1_lone_ignored.sh ignored/third_party/bad_syntax_ignored.sh
-stdout -count=1 'input\.sh$'
+stdout -count=2 'input\.sh$'
 ! stdout 'ignored\.sh'
 ! stderr .
 exec shfmt --apply-ignore input.sh ignored/1_lone_ignored.sh ignored/third_party/bad_syntax_ignored.sh

go.mod

@@ -8,7 +8,6 @@ require (
  github.com/google/go-cmp v0.6.0
  github.com/google/renameio/v2 v2.0.0
  github.com/muesli/cancelreader v0.2.2
- github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e
  github.com/rogpeppe/go-internal v1.12.0
  golang.org/x/sync v0.7.0
  golang.org/x/sys v0.19.0

go.sum

@@ -13,7 +13,6 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
 github.com/muesli/cancelreader v0.2.2/go.mod h1:3XuTXfFS2VjM+HTLZY9Ak0l6eUKfijIfMUZ4EgX0QYo=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e h1:aoZm08cpOy4WuID//EZDgcC4zIxODThtZNPirFr42+A=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.12.0 h1:exVL4IDcn6na9z1rAb56Vxr+CgyK3nn3O+epU5NdKM8=