zed-industries/zed · error

couldn't resolve hunk

Error message

couldn't resolve hunk

What it means

A parsed udiff hunk could not be matched to any location in the target text: neither context-line search nor line-number disambiguation produced a usable offset in apply_diff_to_string_with_hunk_offset. Usually means the diff context no longer matches the buffer (stale text or earlier hunks shifted lines).

Source

Thrown at crates/zeta_prompt/src/udiff.rs:413

    let mut line_delta = 0i64;

    while let Some(event) = diff.next().context("Failed to parse diff")? {
        match event {
            DiffEvent::Hunk {
                mut hunk,
                path: _,
                status: _,
            } => {
                let candidates = find_context_candidates(&text, &mut hunk);
                let adjusted_start_line = hunk
                    .start_line
                    .and_then(|start_line| u32::try_from(start_line as i64 + line_delta).ok());

                let hunk_offset =
                    disambiguate_by_line_number(&candidates, adjusted_start_line, &|offset| {
                        text[..offset].matches('\n').count() as u32
                    })
                    .ok_or_else(|| anyhow!("couldn't resolve hunk"))?;

                if first_hunk_offset.is_none() {
                    first_hunk_offset = Some(hunk_offset);
                }

                let mut hunk_line_delta = 0i64;
                for edit in hunk.edits.iter().rev() {
                    let range = (hunk_offset + edit.range.start)..(hunk_offset + edit.range.end);
                    let deleted_lines = text[range.clone()].matches('\n').count() as i64;
                    let inserted_lines = edit.text.matches('\n').count() as i64;
                    text.replace_range(range, &edit.text);
                    hunk_line_delta += inserted_lines - deleted_lines;
                }
                line_delta += hunk_line_delta;
            }
            DiffEvent::FileEnd { .. } => {
                line_delta = 0;
            }

View on GitHub (pinned to f4178619ac)

Solutions

1. Regenerate the diff against the current buffer contents and reapply
2. Fall back to fuzzy/whitespace-relaxed context matching before giving up
3. Track cumulative line_delta across hunks so later hunks resolve against already-patched text

When it happens

Trigger: Thrown at crates/zeta_prompt/src/udiff.rs:413 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/a95c778230fb557f. Report an issue: GitHub.