[BUG] v1.2.0 seems to produce incorrect diff

[KevinWang15]

This testcase:

func Test(t *testing.T) {
	src := "a\na: a\na:\n  a:\n    a\n    a: \"a\"\n    a: a\n    a: \"1\"\n    a: 1\n    -"
	dst := "abcde: xxxxx"

	dmp := New()
	wSrc, wDst, warray := dmp.DiffLinesToRunes(src, dst)
	diffs := dmp.DiffMainRunes(wSrc, wDst, false)
	diffs = dmp.DiffCharsToLines(diffs, warray)

	fmt.Printf("SRC:\n%s\n\nDST:\n%s\n\nDiff:\n%v", src, dst, diffs)
}

Will produce

SRC:
a
a: a
a:
  a:
    a
    a: "a"
    a: a
    a: "1"
    a: 1
    -

DST:
abcde: xxxxx

Diff:
[{Equal a
} {Delete a: a
a:
  a:
    a
    a: "a"
    a: a
    a: "1"
    a: 1
} {Equal a
} {Delete }]

In v1.2.0, which is incorrect.

In v1.1.0, it produces the correct diff of

SRC:
a
a: a
a:
  a:
    a
    a: "a"
    a: a
    a: "1"
    a: 1
    -

DST:
abcde: xxxxx

Diff:
[{Delete a
a: a
a:
  a:
    a
    a: "a"
    a: a
    a: "1"
    a: 1
    -} {Insert abcde: xxxxx}]

[eastlondoner]

I'm seeing this problem as well. I had to revert to 1.1.0

[peter-evans]

I also had this problem. All the examples I could find were producing garbage results until I found this issue and realised that 1.2.0 was the culprit. Switched to version 1.1.0 and all seems fine.

[KevinWang15]

@sergi Please take a look when possible, as many other libraries are depending on this one, thanks!

[schrej]

This was broken with db1b095 by passing a array to diffLinesToStringsMunge instead of a map.

Calling that function with multiple files, but passing the same array, now leads to duplicated lines for each file in the array, instead of re-using existing lines.

[aymanbagabas]

Any updates here?

[huguesalary]

I ran into this issue as well. Reverting to 1.1.0 fixes it.

[uhthomas]

go mod edit -exclude=github.com/sergi/go-diff@v1.2.0

may be helpful to prevent an accidental upgrade with go mod tidy or go get -u ./....

[kdarkhan]

I created #136 which should fix the issue.

[AriehSchneier]

@sergi Any chance of merging #120 or #136 to fix this? This library is currently giving incorrect results.

[kdarkhan]

#136 was merged yesterday, so this should be resolved now.