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Hacking guide
Although pyelftools is functional and very useful already, it still needs a lot of work. Some things are still missing (see the "Limitations" section in the user guide, and there are surely some bugs left to smoke out.
Contributing to pyelftools is really easy, since it's a completely open-source project, with the code being in the public domain and easily available on Github. The git repository can be cloned at any time with the latest code which hasn't made it into a release version yet. My methodology is to keep trunk master branch) stable, so it's quite usable (sometimes even more so than the released version, since it may contain bug fixes).
Please open Github pull requests for contributions. Make sure to add tests, unless the code you're affecting is already covered by existing tests.
Opening issues in the tracker is also appreciated for reporting problems you ran into but can't or don't want to solve on your own.
Finally, creating clones of other binutils tools (such as nm) with pyelftools will be really nice. In general, any additional work done using pyelftools helps refine and test the library.
Tests must be run from the root development directory of pyelftools.
Since pyelftools essentially clones the functionality of some existing tools in GNU binutils, it can be tested comprehensively by a simple method of output comparison.
This is implemented in test/run_readelf_tests.py, which runs the scripts/readelf.py script on a set of files with a variety of options, and compares its output with the system's installed readelf.
Failures in this test suite frequently result from minor differences in the output of readelf, which tends to change between versions. It may also depend on the system the tool is run on (I run it on 64-bit Ubuntu, x86-64). Take a look at the READELF_PATH variable in test/run_readelf_tests.py to get an idea of the binutils version used.
While initially the readelf comparison tests were top priority because of the great coverage they provided relatively "for free", with time unit testing also became important in pyelftools, due to intricacies of some of the modules, especially in the DWARF parsing parts.
In addition, as the library gains maturity with time, bug fixes should be verified by creating reproducer unit tests, to avoid the bugs coming back in the future.
All unit tests can be executed by running test/run_all_unittests.py.
pyelftools comes with a few usage examples. I consider them a very important part of the documentation, and therefore they should always be kept functional.
To accomplish this, a special test script named test/run_examples_test.py runs all examples on a sample ELF file, and compares the output to a saved "reference" output. This makes sure that the examples work correctly at all times.
To run all of the tests for all Python versions supported by pyelftools, the tox test automation tool is used. The tox.ini file that can be found in the root directory of pyelftools defines the configuration needed for tox to run. A simple invocation of tox from the root directory will install pyelftools in virtual environments, and run all tests for all supported Python versions.
While performance is important for reading large ELF files, it is not the main design goal of pyelftools. That said, performance is not neglected, and I do profile and optimize pyelftools occasionally when something is running slower than expected. I don't want to start growing C-extensions on top of it however. Pure Python is an important design goal. I prefer to make pyelftools run on PyPy for improving performance.
If you think that pyelftools runs too slowly for some particular file, please open an issue and I'll see what can be done.
pyelftools is written in Python, following the PEP 8 style guide.
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