chore: Switch to github.com/pkg/diff for diffing

coder · mafredri · Jun 8, 2022 · May 30, 2022 · May 30, 2022 · May 30, 2022
commit 4f03415e073e709697794e29bcdff27d91da1212
diff --git a/cli/configssh.go b/cli/configssh.go
@@ -7,13 +7,14 @@ import (
 	"io"
 	"io/fs"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"runtime"
 	"sort"
 	"strings"
 
 	"github.com/cli/safeexec"
+	"github.com/pkg/diff"
+	"github.com/pkg/diff/write"
 	"github.com/spf13/cobra"
 	"golang.org/x/exp/slices"
 	"golang.org/x/sync/errgroup"
@@ -383,40 +384,27 @@ func currentBinPath(cmd *cobra.Command) (string, error) {
 
 // diffBytes two byte slices as if they were in a file named name.
 // Does best-effort cleanup ignoring non-critical errors.
-func diffBytes(name string, b1, b2 []byte) (data []byte, err error) {
-	f1, err := os.CreateTemp("", "coder_config-ssh.")
-	if err != nil {
-		return nil, xerrors.Errorf("create temp 1 file failed: %w", err)
-	}
-	defer os.Remove(f1.Name())
-	defer f1.Close()
-
-	f2, err := os.CreateTemp("", "coder_config-ssh.")
-	if err != nil {
-		return nil, xerrors.Errorf("create temp 2 file failed: %w", err)
+func diffBytes(name string, b1, b2 []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	var opts []write.Option
+	// TODO(mafredri): Toggle color on/off
+	if false {
+		opts = append(opts, write.TerminalColor())
 	}
-	defer os.Remove(f2.Name())
-	defer f2.Close()
-
-	_, err = f1.Write(b1)
+	err := diff.Text(name, name+".new", b1, b2, &buf, opts...)
 	if err != nil {
-		return nil, xerrors.Errorf("write temp 1 file failed: %w", err)
-	}
-	_, err = f2.Write(b2)
-	if err != nil {
-		return nil, xerrors.Errorf("write temp 2 file failed: %w", err)
-	}
-
-	// TODO(mafredri): Ensure diff binary exists, or return useful error when missing.
-	data, err = exec.Command("diff", "-u", f1.Name(), f2.Name()).Output() // #nosec
-	if len(data) == 0 && err != nil {                                     // Ignore non-zero exit when files differ.
 		return nil, err
 	}
-	// Replace temp file names with friendly names.
-	data = bytes.Replace(data, []byte(f1.Name()), []byte(name), 1)
-	data = bytes.Replace(data, []byte(f2.Name()), []byte(name+".new"), 1)
-
-	return data, err
+	b := buf.Bytes()
+	// Check if diff only output two lines, if yes, there's no diff.
+	//
+	// Example:
+	// 	--- ~/.ssh/config
+	// 	+++ ~/.ssh/config.new
+	if bytes.Count(b, []byte{'\n'}) == 2 {
+		b = nil
+	}
+	return b, nil
 }
 
 // stripOldConfigBlock is here to migrate users from old config block

diff --git a/go.mod b/go.mod
@@ -93,6 +93,7 @@ require (
 	github.com/pion/udp v0.1.1
 	github.com/pion/webrtc/v3 v3.1.41
 	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8
+	github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e
 	github.com/pkg/sftp v1.13.4
 	github.com/prometheus/client_golang v1.12.2
 	github.com/quasilyte/go-ruleguard/dsl v0.3.21

diff --git a/go.sum b/go.sum
@@ -1336,6 +1336,7 @@ github.com/pires/go-proxyproto v0.6.2/go.mod h1:Odh9VFOZJCf9G8cLW5o435Xf1J95Jw9G
 github.com/pkg/browser v0.0.0-20210706143420-7d21f8c997e2/go.mod h1:HKlIX3XHQyzLZPlr7++PzdhaXEj94dEiJgZDTsxEqUI=
 github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 h1:KoWmjvw+nsYOo29YJK9vDA65RGE3NrOnUtO7a+RF9HU=
 github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8/go.mod h1:HKlIX3XHQyzLZPlr7++PzdhaXEj94dEiJgZDTsxEqUI=
+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/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1-0.20171018195549-f15c970de5b7/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=