A native Python cross-version Decompiler and Fragment Decompiler. Follows in the tradition of decompyle, uncompyle, and uncompyle2.

uncompyle6 translates Python bytecode back into equivalent Python source code. It accepts bytecodes from Python version 2.2 to 3.6 or so, including PyPy bytecode.

There were a number of decompyle, uncompile, uncompyle2, uncompyle3 forks around. All of them came basically from the same code base, and almost all of them no were no longer actively maintained. Only one handled Python 3, and even there, only 3.2. This code pulls these together and moves forward. It also addresses a number of open issues in the previous forks.

What makes this different from other CPython bytecode decompilers?: its ability to deparse just fragments and give source-code information around a given bytecode offset.

I use this to deparse fragments of code inside my trepan debuggers. For that, I need to record text fragments for all bytecode offsets (of interest). This purpose although largely compatible with the original intention is yet a little bit different. See this for more information.

The idea of Python fragment deparsing given an instruction offset can be used in showing stack traces or any program that wants to show a location in more detail than just a line number. It can be also used when source-code information does not exist and there is just bytecode information.

This project requires Python 2.6 or later, PyPy 3-2.4, or PyPy-5.0.1. The bytecode files it can read has been tested on Python bytecodes from versions 2.2-2.7, and 3.2-3.6 and the above-mentioned PyPy versions.

This uses setup.py, so it follows the standard Python routine:

pip install -r requirements.txt
pip install -r requirements-dev.txt
python setup.py install # may need sudo
# or if you have pyenv:
python setup.py develop

A GNU makefile is also provided so make install (possibly as root or sudo) will do the steps above.

make check

A GNU makefile has been added to smooth over setting running the right command, and running tests from fastest to slowest.

If you have remake installed, you can see the list of all tasks including tests via remake --tasks

Run

$ uncompyle6 *compiled-python-file-pyc-or-pyo*

For usage help:

$ uncompyle6 -h

Python 2 deparsing decompiles and about 90% verifies from Python 2.3.7 to Python 3.4.2 on the standard library packages I have on my system.

(Verification is the process of decompiling bytecode, compiling with a Python for that byecode version, and then comparing the byetcode produced by the decompiled/compiled program. Some allowance is made for inessential differences.)

Later distributions average about 200 files. At this point, 2.7 decompilation is better than uncompyle2. A number of bugs have been fixed.

Python 3.5 largely works, but still has some bugs in it. Python 3.6 changes things drastically by using word codes rather than byte codes, and that needs to be addressed.

There is lots to do, so please dig in and help.

• https://github.com/zrax/pycdc : supports all versions of Python and is written in C++
• https://code.google.com/archive/p/unpyc3/ : supports Python 3.2 only. The above projects use a different decompiling technique what is used here.
• The HISTORY file.