feat: Add code_x_glue code_to_code task

[jonleinena]

Pull Request: Add CodeXGLUE Code-to-Code Translation Task with CodeBLEU Metric

Summary

This PR adds support for the CodeXGLUE Code-to-Code Translation benchmark, enabling evaluation of models on translating code between Java and C# using the CodeBLEU metric.

Motivation

CodeBLEU is the recommended metric for code translation tasks as it goes beyond standard BLEU by considering:

• N-gram matching (like BLEU)
• Weighted n-gram matching based on syntax
• AST-based syntax matching
• Dataflow matching for semantic similarity

This makes it particularly suited for evaluating code generation and translation quality.

Changes

New Files

• bigcode_eval/tasks/codexglue_code_to_code_trans.py - Task implementation
• bigcode_eval/tasks/few_shot_examples/codexglue_code_to_code_trans_few_shot_prompts.json - Few-shot examples
• requirements-codebleu.txt - CodeBLEU dependency

Modified Files

• bigcode_eval/tasks/__init__.py - Register the new task
• requirements.txt - Add tree-sitter dependencies
• README.md - Document the new task and installation instructions

New Tasks

Task Name	Description
codexglue_code_to_code_trans-java_cs	Java → C# translation
codexglue_code_to_code_trans-cs_java	C# → Java translation

Installation

Due to a dependency conflict between codebleu and newer tree-sitter versions, install with:

pip install -r requirements-codebleu.txt --no-deps
pip install -r requirements.txt

This installs codebleu without its dependencies first (bypassing the tree-sitter>=0.22.0,<0.23.0 constraint), then installs the compatible tree-sitter==0.25.2 packages required by the language parsers.

Usage

accelerate launch main.py \
  --model <MODEL_NAME> \
  --tasks codexglue_code_to_code_trans-java_cs \
  --max_length_generation 512 \
  --n_samples 1 \
  --batch_size 1 \
  --save_generations

Dataset

• Source: google/code_x_glue_cc_code_to_code_trans
• Test samples: 1,000
• Languages: Java ↔ C#
• Evaluation: 2-shot prompting with CodeBLEU scoring

References

• CodeXGLUE Paper: https://arxiv.org/abs/2102.04664
• CodeBLEU Paper: https://arxiv.org/abs/2009.10297

Checklist

• The title is a summary of the contribution
• All public methods have informative docstrings
• Existing tests pass