pydry

pydry is a small Python CLI for finding exact duplicate functions and structurally similar functions in Python code.

Features

• Finds exact duplicate functions using AST normalization.
• Ranks near matches by structural similarity and refactorability.
• Flags likely abstraction candidates and common risk signals.
• Emits text output for quick inspection and JSON output for automation.
• Runs without third-party runtime dependencies.

Installation

python -m pip install pydry-cli

For local development from a checkout:

make venv
source venv/bin/activate
make install
make check

Quick start

Run a compact summary for the current directory:

pydry showcase

Find exact duplicates:

pydry exact ./src --normalize-local-names --normalize-constants

Find near matches:

pydry near ./src --threshold 0.85 --top-k 25

Write a full JSON report:

pydry report ./src --output reports/pydry-report.json

Commands

pydry exact

Find exact duplicate functions after AST normalization.

pydry exact ./src
pydry exact ./src --min-count 3
pydry exact ./src --normalize-local-names --normalize-constants
pydry exact ./src --format json

Useful options:

• --min-count: minimum group size, default 2.
• --top-level-only: ignore nested functions and methods.
• --normalize-local-names: treat local variable renames as equivalent.
• --normalize-constants: treat many literal value changes as equivalent.
• --include-canonical: include canonical AST dumps in JSON output.
• --strict: fail on files that cannot be read or parsed.

pydry near

Rank structurally similar function pairs.

pydry near ./src
pydry near ./src --threshold 0.85 --top-k 25
pydry near ./src --format json --output reports/near.json

Useful options:

• --threshold: similarity threshold from 0 to 1, default 0.8.
• --top-k: cap the number of returned pairs.
• --top-level-only: ignore nested functions and methods.
• --strict: fail on files that cannot be read or parsed.

pydry abstract

Filter near matches to pairs that look like plausible refactor candidates.

pydry abstract ./src
pydry abstract ./src --threshold 0.86 --format json

pydry report

Generate one JSON document with exact, near, and abstract sections.

pydry report ./src
pydry report ./src --threshold 0.82 --top-k 250 --output reports/pydry-report.json

pydry showcase and pydry simulate

Run a compact terminal summary. Both commands use the same analysis pipeline. With no path, they scan the current directory.

pydry showcase
pydry showcase ./src --top-k 10 --threshold 0.8
pydry showcase ./src --format json
pydry simulate ./src

JSON output

JSON-capable commands return an envelope:

{
  "results": [],
  "diagnostics": {
    "scan_errors_count": 0,
    "scan_error_samples": [],
    "plugin_errors_count": 0,
    "plugin_error_samples": []
  }
}

Near and abstract entries include:

• similarity_score
• refactorability_score
• pattern_labels
• shared_structure_summary
• key_differences
• risk_flags
• suggested_refactor_kind
• evidence

Python API

The CLI is the primary interface, but the core functions are importable:

from pathlib import Path

from pydry.engine import exact_groups, near_matches

groups = exact_groups(
    Path("src"),
    normalize_local_names=True,
    normalize_constants=True,
)
rows = near_matches(Path("src"), threshold=0.85, top_k=25)

Limitations

• Similarity is heuristic. It does not prove semantic equivalence.
• Cross-file import resolution is not attempted.
• Generated abstraction templates are suggestions, not executable patches.

Development

make check
make coverage
make check-dist

The package supports Python 3.11 and newer.

License

pydry is released under the MIT License. See LICENSE.