go-diff-fmt

Diff formatting library for Go.

For example, it can format line based diff by github.com/sergi/go-diff to Unified format.

NOTICE:

DiffLinesToChars of github.com/sergi/go-diff@v1.2.0 contains bugs, so in order to work properly this module, it requires v1.1.0.

Install

$ go get github.com/mrk21/go-diff-fmt/...

Usage

main.go:

package main

import (
	"github.com/mrk21/go-diff-fmt/difffmt"
	"github.com/sergi/go-diff/diffmatchpatch"
)

func main() {
	targetA := difffmt.NewDiffTarget("a.txt")
	targetB := difffmt.NewDiffTarget("b.txt")
	_ = targetA.LoadStat()
	_ = targetB.LoadStat()
	textA, _ := targetA.ReadText()
	textB, _ := targetB.ReadText()

	// Computing a line-mode diff
	// @see https://github.com/google/diff-match-patch/wiki/Line-or-Word-Diffs
	dmp := diffmatchpatch.New()
	runes1, runes2, lineArray := dmp.DiffLinesToRunes(textA, textB)
	diffs := dmp.DiffMainRunes(runes1, runes2, false)
	diffs = dmp.DiffCharsToLines(diffs, lineArray)

	// Format `[]diffmatchpatch.Diff` to Unified format
	lineDiffs := difffmt.MakeLineDiffsFromDMP(diffs)
	hunks := difffmt.MakeHunks(lineDiffs, 3)
	unifiedFmt := difffmt.NewUnifiedFormat(difffmt.UnifiedFormatOption{
		ColorMode: difffmt.ColorTerminalOnly,
	})
	unifiedFmt.Print(targetA, targetB, hunks)
}

a.txt:

line1
line2
line3
line4
line5
line6
line8
line9
line10
line11
line12

b.txt:

line1
line2
line3
line4
line5b
line6
line7b
line8b
line9
line10
line11
line12
line13
line14

$ go run main.go
--- a.txt       2022-06-13 14:07:47.670396312 +0900
+++ b.txt       2022-06-13 14:08:03.390396269 +0900
@@ -2,10 +2,13 @@
 line2
 line3
 line4
-line5
+line5b
 line6
-line8
+line7b
+line8b
 line9
 line10
 line11
 line12
+line13
+line14

References

• Unified Diff Format
• Detailed Unified (Comparing and Merging Files)
• diff - Wikipedia
• Line or Word Diffs · google/diff-match-patch Wiki