micro-editor/micro · warning

no diff data

Error message

no diff data

What it means

Returned by (*Buffer).FindNextDiffLine (internal/buffer/buffer.go:1434) when b.diff is nil — the buffer has no diff state yet. Diff data is only populated after a diff has been computed against the file's git history (the > diff command / diff gutter feature). Calling NextDiff/PrevDiff (internal/action/actions.go:1279/1290) before that is a sequence error: 'compute a diff first'.

Source

Thrown at internal/buffer/buffer.go:1434

	} else {
		b.diffBaseLineCount = strings.Count(string(diffBase), "\n")
	}
	b.UpdateDiff()
}

// DiffStatus returns the diff status for a line in the buffer
func (b *Buffer) DiffStatus(lineN int) DiffStatus {
	b.diffLock.RLock()
	defer b.diffLock.RUnlock()
	// Note that the zero value for DiffStatus is equal to DSUnchanged
	return b.diff[lineN]
}

// FindNextDiffLine returns the line number of the next block of diffs.
// If `startLine` is already in a block of diffs, lines in that block are skipped.
func (b *Buffer) FindNextDiffLine(startLine int, forward bool) (int, error) {
	if b.diff == nil {
		return 0, errors.New("no diff data")
	}
	startStatus, ok := b.diff[startLine]
	if !ok {
		startStatus = DSUnchanged
	}
	curLine := startLine
	for {
		curStatus, ok := b.diff[curLine]
		if !ok {
			curStatus = DSUnchanged
		}
		if curLine < 0 || curLine > b.LinesNum() {
			return 0, errors.New("no next diff hunk")
		}
		if curStatus != startStatus {
			if startStatus != DSUnchanged && curStatus == DSUnchanged {
				// Skip over the block of unchanged text
				startStatus = DSUnchanged

View on GitHub (pinned to 1c8b82b32e)

Solutions

1. Run > diff first; afterwards NextDiff/PrevDiff have data to walk
2. Confirm the file lives inside a git work tree — with no VCS info there is never diff data
3. In code, ensure the diff was requested (b.diff != nil equivalent) before navigating; see validation snippet for the caller-side ordering

Example fix

// before
h.Buf.FindNextDiffLine(cur, true) // -> no diff data

// after
h.DoCommand("diff")
dl, err := h.Buf.FindNextDiffLine(cur, true)

// Establish diff state before navigating hunks
cur := h.Buf.GetActiveCursor().Y
if h.Buf.DiffStatus(cur) == buffer.DSUnchanged {
    // can't distinguish 'no diff yet' from 'unchanged line' — so ensure the
    // diff command ran for this buffer before exposing Next/PrevDiff keys
    h.DoCommand("diff")
}
dl, err := h.Buf.FindNextDiffLine(cur, true)

dl, err := h.Buf.FindNextDiffLine(cur, true)
if err != nil {
    if err.Error() == "no diff data" {
        InfoBar.Message("run > diff first")
        return // sequence error, not fatal
    }
    InfoBar.Error(err)
}

When it happens

Trigger: Opening a file and immediately invoking the NextDiff or PrevDiff action (default bindings on Ctrl-n/Ctrl-p family in diff mode) without ever running > diff; the diff buffer state was reset after a reload or after switching buffers in the same tab.

Common situations: Keybindings copied from a diff-heavy workflow; plugins calling FindNextDiffLine directly; users expecting automatic git-diff like gutter plugins in other editors.

Related errors

• no next diff hunk
• Not enough arguments
• Error: %s is a directory and cannot be opened
• Error: %s is not a regular file and cannot be opened
• could not open file

AI-assisted analysis of micro-editor/micro@1c8b82b32e (2026-08-15). Data as JSON: /api/errors/ddcd8d338c3e2604. Report an issue: GitHub.