---
task_categories:
- text-generation
- code-generation
- code-understanding
tags:
- diff-understanding
- benchmark
dataset_info:
  features:
  - name: repo
    dtype: string
  - name: commit
    dtype: string
  - name: path
    dtype: string
  - name: lang
    dtype: string
  - name: license
    dtype: string
  - name: message
    dtype: string
  - name: old_code
    dtype: string
  - name: new_code
    dtype: string
  - name: n_added
    dtype: int64
  - name: n_removed
    dtype: int64
  - name: n_hunks
    dtype: int64
  - name: change_kind
    dtype: string
  - name: udiff
    dtype: string
  - name: udiff-h
    dtype: string
  - name: udiff-l
    dtype: string
  - name: search-replace
    dtype: string
  splits:
  - name: test
    num_bytes: 5891980
    num_examples: 1000
  download_size: 2695508
  dataset_size: 5891980
configs:
- config_name: default
  data_files:
  - split: test
    path: data/test-*
---

# Diff-XYZ

This is a dataset for the paper: [Diff-XYZ: A Benchmark for Evaluating Diff Understanding](https://arxiv.org/abs/2510.12487).

Diff-XYZ contains 1,000 real-world code edits sampled and filtered from
the [CommitPackFT](https://huggingface.co/datasets/bigcode/commitpackft) dataset.  
Each example provides three components: the original file contents (`old_code`), the modified contents (`new_code`), and
multiple diff representations (`udiff`, `udiff-h`, `udiff-l`, and `search-replace`).

These formats enable evaluation of LLM capabilities on three code editing tasks:

-   **Apply**: Given old code and diff, generate new code
-   **Anti-Apply**: Given new code and diff, generate old code
-   **Diff-Generation**: Given old and new code, generate the diff

## How it's built

Examples were systematically filtered from CommitPackFT to ensure high quality:

-   **Scope**: Single-file changes only, excluding binary files, vendor directories, and generated code
-   **Quality**: Removed trivial changes (whitespace-only) and likely test files
-   **Size**: Required 40+ lines in at least one version of the code (old or new); excluded very large files (1000+ lines)
-   **Sampling**:
    -   Target 50/50 split between single-hunk and multi-hunk edits (hunks counted via `@@` markers in the unified diff).
    -   Within each hunk group, stratify by change size (lines added + removed) using the 40th/80th percentiles of that
        group, targeting ≈40% small, 40% medium, 20% large.
    -   Cap examples to ≤5 per repository per language.

## Dataset Statistics

-   **Total examples:** 1,000
-   **Languages:** Python (200), JavaScript (200), Java (200), Kotlin (200), Rust (200)

**Hunks:**

-   **1 hunk:** 500 (50.0%)
-   **2+ hunks:** 500 (50.0%)

**Change size (added + removed), stratified within hunk groups:**

-   **Small** (≤40th pct): 424 (42.4%)
-   **Medium** (40th–80th): 388 (38.8%)
-   **Large** (>80th): 188 (18.8%)

**Change type:**

-   **Mixed** (additions + deletions): 815 (81.5%)
-   **Add-only:** 163 (16.3%)
-   **Delete-only:** 22 (2.2%)

**Repository diversity:** 891 unique repositories.

## Schema

| Field            | Type   | Description                                                            |
|------------------|--------|------------------------------------------------------------------------|
| `repo`           | string | Repository identifier (e.g., "owner/name")                             |
| `commit`         | string | Commit SHA that produced the change                                    |
| `path`           | string | File path relative to repo root                                        |
| `lang`           | string | One of: `python`, `javascript`, `java`, `kotlin`, `rust`               |
| `license`        | string | SPDX license identifier of the repo                                    |
| `message`        | string | Original commit message                                                |
| `old_code`       | string | Complete file contents before change                                   |
| `new_code`       | string | Complete file contents after change                                    |
| `n_added`        | int    | # of `+` lines (excluding headers)                                     |
| `n_removed`      | int    | # of `-` lines (excluding headers)                                     |
| `n_hunks`        | int    | # of `@@` (hunk) sections                                              |
| `change_kind`    | string | `add_only`, `del_only`, or `mixed`                                     |
| `udiff`          | string | Standard unified diff (1-line context, numeric hunk headers)           |
| `udiff-h`        | string | Unified diff with relaxed hunk headers written as `@@ ... @@`          |
| `udiff-l`        | string | Unified diff with explicit line markers: `ADD`, `DEL`, and `CON`       |
| `search-replace` | string | Search/replace representation: pairs of `SEARCH`/`REPLACE` edit blocks |