Py2py3 Converter

py2py3-converter

1. Introduction

py2py3-converter is an OpenClaw skill that automatically converts legacy Python 2 code to modern Python 3 syntax. It handles the most common migration patterns, generates compatibility reports, and creates unit tests for the converted code.

Python 2 reached end-of-life on January 1, 2020, yet many codebases still contain Python 2 code. This skill automates the tedious work of manual migration, reducing human error and accelerating the upgrade process.

2. Core Capabilities

Conversion Logic

The converter handles these Python 2 → 3 transformations:

• print statements → print() function calls
• raw_input() → input()
• xrange() → range()
• unicode() → str()
• basestring → str
• long type → int
• dict.has_key(k) → k in dict
• except Exception, e → except Exception as e
• raise ValueError, "msg" → raise ValueError("msg")
• Integer division / awareness
• __future__ import removal
• iteritems() / itervalues() / iterkeys() → items() / values() / keys()
• reduce() → functools.reduce()

Compatibility Checking

After conversion, a compatibility report is generated listing:

• Warnings for patterns that may need manual review
• Errors for constructs that could not be safely converted
• Informational notes about behavior changes

Test Generation

For each converted file, a companion pytest test file is generated that:

• Validates syntax correctness of converted code
• Tests key functions for expected behavior
• Covers detected edge cases

3. Edge Cases Handling

Print Statements

• print "hello" → print("hello")
• print "a", "b" → print("a", "b")
• print >> sys.stderr, "err" → print("err", file=sys.stderr)
• print() already valid → left unchanged

String/Bytes Compatibility

• u"string" prefix → "string" (default in Python 3)
• Warns about b"bytes" patterns that may need review
• basestring references → str

Import Resolution

• from __future__ import print_function → removed (default in Python 3)
• import urllib2 → import urllib.request
• import ConfigParser → import configparser
• reduce → adds from functools import reduce

4. CLI Interface

Command Syntax

# Convert a file
node scripts/cli.js convert --input path/to/py2file.py --output path/to/py3file.py

# Convert from stdin
cat py2file.py | node scripts/cli.js convert

# Convert and generate tests
node scripts/cli.js convert --input file.py --output converted.py --generate-tests

# Show compatibility report only
node scripts/cli.js check --input file.py

Exit Codes

• 0 - Conversion successful, no errors
• 1 - Conversion completed with warnings
• 2 - Conversion failed due to errors

5. Integration

OpenClaw Agent Workflow

Agents invoke the skill via the CLI interface. The standard workflow:

1. Agent receives Python 2 code from user
2. Agent calls node scripts/cli.js convert --input <file>
3. Skill returns converted code + compatibility report
4. Agent presents results to user

API Contract

Input:

{
  "code": "print 'hello world'",
  "options": {
    "generateTests": false,
    "keepWarnings": true
  }
}

Output:

{
  "convertedCode": "print('hello world')",
  "issues": [
    {
      "type": "info",
      "line": 1,
      "message": "Converted print statement to function call"
    }
  ]
}