Nagini is an automatic verifier for statically typed Python programs, based on the Viper verification infrastructure. Nagini is being developed at the Chair of Programming Methodology at ETH Zurich as part of the VerifiedSCION project.
You can try a (rather slow) online version of Nagini on this website.
For use with the PyCharm IDE, try the Nagini PyCharm plugin.
Dependencies (Ubuntu Linux)
Install Java 11 or newer (64 bit) and Python 3.7 or newer (64 bit) and the required libraries:
sudo apt-get install python3-dev
For usage with Viper's verification condition generation backend Carbon, you will also need to install Boogie.
- Install Java 11 or newer (64 bit) and Python 3.7 or newer (64 bit).
- Install either Visual C++ Build Tools 2015 (http://go.microsoft.com/fwlink/?LinkId=691126) or Visual Studio 2015. For the latter, make sure to choose the option "Common Tools for Visual C++ 2015" in the setup (see https://blogs.msdn.microsoft.com/vcblog/2015/07/24/setup-changes-in-visual-studio-2015-affecting-c-developers/ for an explanation).
Create a virtual environment:
virtualenv --python=python3 <env>
pip install nagini
Alternatively, to get the most up-to-date version, install from source; this will require manually getting and compiling Viper (most likely the most recent development version):
git clone https://github.com/marcoeilers/nagini.git cd nagini pip install .
Command Line Usage
To verify a specific file from the nagini directory, run:
nagini [OPTIONS] path-to-file.py
The following command line options are available:
--verifier Selects the Viper backend to use for verification. Possible options are 'silicon' (for Symbolic Execution) and 'carbon' (for Verification Condition Generation based on Boogie). Default: 'silicon'. --select Select which functions/methods/classes to verify. Expects a comma- separated list of names. --counterexample Enable outputting counterexamples for verification errors (experimental). --z3 Sets the path of the Z3 executable. Alternatively, the 'Z3_EXE' environment variable can be set. --boogie Sets the path of the Boogie executable. Required if the Carbon backend is selected. Alternatively, the 'BOOGIE_EXE' environment variable can be set. --viper-jar-path Sets the path to the required Viper binaries ('silicon.jar' or 'carbon.jar'). Only the binary for the selected backend is required. You can either use the provided binary packages installed by default or compile your own from source (see below). Expects either a single path or a colon- (Unix) or semicolon- (Windows) separated list of paths. Alternatively, the environment variables 'SILICONJAR', 'CARBONJAR' or 'VIPERJAR' can be set.
To see all possible command line options, invoke
nagini without arguments.
Alternative Viper Versions
To use a more recent or custom version of the Viper infrastructure, follow the
instructions here. Look for
sbt assembly to find instructions for packaging the required JAR files. Use the
parameters mentioned above to instruct Nagini to use your custom Viper version.
On Windows: During the setup, you get an error like
Microsoft Visual C++ 14.0 is required.or
Unable to fnd vcvarsall.bat:
Python cannot find the required Visual Studio 2015 C++ installation, make sure you have either installed the Build Tools or checked the "Common Tools" option in your regular VS 2015 installation (see above).
While verifying a file, you get a stack trace ending with something like
No matching overloads found:
The version of Viper you're using does not match your version of Nagini. Try updating both to the newest version.