6.1 KiB
How to report a Bug
The difficulty of the problem
This decompiler is a constant work in progress: Python keeps changing, and so does its code generation.
There is no Python decompiler yet that I know about that will decompile everything. Overall, I think this one probably does the best job of any Python decompiler that handles such a wide range of versions.
But at any given time, there are maybe dozens of valid Python bytecode files that I know of that will cause problems. And when I get through those and all the issues of decompiler bugs that are currently logged, I could probably easily find dozens more bugs just by doing a decompile of all the Python bytecode on any one of my computers. Unless you want to help out by fixing bugs, or are willing to do work by isolating and narrowing bugs, don't feel you are doing me a favor by doing scans on your favorite sets of bytecode files.
In sum, it is not uncommon that you will find a mistranslation in decompiling. Furthermore, you may be expected to do some work in order to have your bug worthy of being considered above other bugs.
No one is getting paid to work to work on this project, let alone bugs you may have an interest in. If you require decompiling bytecode immediately, consider using a decompilation service.
Is it really a bug?
Do you have valid bytecode?
As mentioned in README.rst, this project doesn't handle obfuscated code. See README.rst for suggestions for how to remove some kinds of obfuscation.
Checking if bytecode is valid is pretty simple: disassemble the code.
Python comes with a disassembly module called dis. A prerequisite
module for this package, xdis has a cross-python version
disassembler.
Semantic equivalence vs. exact source code
Almost all versions of Python can perform some sort of code improvement that can't be undone. In earlier versions of Python it is rare; in later Python versions, it is more common.
If the code emitted is semantically equivalent, then this isn't a bug.
For example the code might be
if a:
if b:
x = 1
and we might produce:
if a and b:
x = 1
These are equivalent. Sometimes
else:
if ...
may come out as elif.
As mentioned in the README, It is possible that Python changes what you write to be more efficient. For example, for:
if True:
x = 5
Python will generate code like:
x = 5
So just because the text isn't the same, does not necessarily mean there's a bug.
What to send (minimum requirements)
The basic requirement is pretty simple:
- Python bytecode
- Python source text
Please don't put files on download services that one has to register
for or can't get to by issuing a simple curl or wget. If you can't
attach it to the issue, or create a github gist, then the code you are
sending is too large.
Also try to narrow the bug. See below.
What to send (additional helpful information)
Some kind folks also give the invocation they used and the output which usually includes an error message produced. This is helpful. From this, I can figure out what OS you are running this on and what version of uncomplye6 was used. Therefore, if you don't provide the input command and the output from that, please give:
- uncompyle6 version used
- OS that you used this on
- Python interpreter version used
But I don't have the source code!
Sure, I get it. No problem. There is Python assembly code on parse errors, so simply by hand decompile that. To get a full disassembly, use pydisasm from the xdis package. Opcodes are described in the documentation for the dis module.
But I don't have the source code and am incapable of figuring how how to do a hand disassembly!
Well, you could learn. No one is born into this world knowing how to disassemble Python bytecode. And as Richard Feynman once said, "What one fool can learn, so can another."
If this is too difficult, or too time consuming, or not of interest to you, then perhaps what require is a decompilation service. Crazy Compilers offers a byte-code decompiler service for versions of Python up to 2.6. (If there are others around let me know and I'll list them here.)
Narrowing the problem
I don't need or want the entire source code base for the file(s) or module(s) can't be decompiled. I just need those file(s) or module(s). If there are problems in several files, file a bug report for each file.
Python modules can get quite large, and usually decompilation problems occur in a single function or maybe the main-line code but not any of the functions or classes. So please chop down the source code by removing those parts that do to decompile properly.
By doing this, you'll probably have a better sense of what exactly is the problem. Perhaps you can find the boundary of what decompiles, and what doesn't. That is useful. Or maybe the same file will decompile properly on a neighboring version of Python. That is helpful too.
In sum, the more you can isolate or narrow the problem, the more likley the problem will be fixed and fixed sooner.
Confidentiality of Bug Reports
When you report a bug, you are giving up confidentiality to the source code and the byte code. However, I would imagine that if you have narrowed the problem sufficiently, confidentiality of the little that remains would not be an issue.
However feel free to remove any commments, and modify variable names or constants in the source code.
Ethics
I do not condone using this program for unethical or illegal purposes. More detestful, at least to me, is asking for help to assist you in something that might not legitimate.
Don't use the issue tracker for such solicitations. To try to stave off illegitimate behavior, you should note that the issue tracker, the code, and bugs mentioned in that are in the open: there is no confidentiality. You may be asked about the authorship or claimed ownership of the bytecode. If I think something is not quite right, I may label the issue questionable which may make the it easier those who are looking for illegal activity.