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a type inferencer and indexer for Python
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PySonar2 - a type inferencer and indexer for Python

PySonar2 is a type inferencer and indexer for Python, which performs sophisticated interprocedural analysis to infer types. It is one of the underlying technologies that power the code search engine Sourcegraph, where it has been used to index hundreds of thousands of open source Python repositories, producing a globally connected network of Python code. An older version of PySonar is used internally at Google, producing high-quality semantic code index for millions of lines of Python code.

To understand its properties, please refer to my blog post:

How to build

mvn package

How to use

PySonar2 is mainly designed as a library for Python IDEs, other developer tools and code search engines, so its interface may not be as appealing as an end-user tool, but for your understanding of the library's capabilities, a reasonably nice demo program has been built.

You can build a simple "code-browser" of the Python 2.7 standard library with the following command line:

java -jar target/pysonar-2.0-SNAPSHOT.jar /usr/lib/python2.7 ./html

This will take a few minutes. You should find some interactive HTML files inside the html directory after this process.

System requirements

  • Python 2.7.x
  • Python 3.x if you have Python3 files
  • Java 7
  • maven
Environment variables

PySonar2 uses CPython's ast package to parse Python code, so please make sure you have python or python3 installed and pointed to by the PATH environment variable. If you have them in different names, please make symbol links.

PYTHONPATH environment variable is used for locating the Python standard libraries. It is important to point it to the correct Python library, for example

export PYTHONPATH=/usr/lib/python2.7

If this is not set up correctly, you may find suboptimal results.

Memory usage

PySonar2 doesn't need much memory to do analysis compared to other static analysis tool of its class. 1.5Gb is probably enough for analyzing a medium sized project such as Python's standard library or Django. But for generating the HTML files, you may need quite some memory (~2.5Gb for Python 2.7 standard lib). This is due to the highlighting code is putting all code and their HTML tags into the memory.

License (GNU AGPLv3)

PySonar - a type inferencer and indexer for Python

Copyright (c) 2013-2014 Yin Wang

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see


If you want to support the development of PySonar, click here to donate:

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