Supported Tools

Prospector currently supports 10 tools, of which 7 are defaults and 3 are optional extras.

Enabling or Disabling Tools

Prospector will run with defaults enabled and optional extras disabled unless configured otherwise.

To specify an exact list of tools to run, for example, only pylint and pep8:

prospector --tool pylint --tool pep8

Note that this command line option will override values set in profiles.

To specify optional extras on top of the defaults, for example, to run defaults and also pyroma without needing to specify the complete list of defaults:

prospector --with-tool pyroma

To run the default tools but turn off one or two defaults:

prospector --without-tool mccabe

Defaults

Pylint

Pylint is the most comprehensive static analysis tool for Python. It is extremely thorough and is the source of most messages that prospector outputs.

pep8.py

pep8.py is a simple tool to warn about violations of the PEP8 style guide. It produces messages for any divergence from the style guide.

Prospector’s concept of strictness turns off various warnings depending on the strictness level. By default, several PEP8 errors will be supressed. To adjust this without adjusting the strictness of other tools, you have some options:

# turn off pep8 checking completely:
prospector --no-style-warnings

# turn on complete pep8 checking:
prospector --full-pep8

# change the maximum line length allowed
# (the default varies by strictness):
prospector --max-line-length 120

pyflakes

Pyflakes analyzes programs and detects various errors. It is simpler and faster than pylint, but also not as thorough.

mccabe

McCabe or cyclomatic complexity is a measurement of how many paths there are in a given function or method. It measures how complicated your functions are, and warns if they reach a certain threshold. Methods that are too complex are prone to logic errors, and should be refactored to a series of smaller methods.

dodgy

Dodgy is a very simple tool designed to find ‘dodgy’ things which should not be in a public project, such as secret keys, passwords, AWS tokens or source control diffs.

pydocstyle

pydocstyle is a simple tool to warn about violations of the PEP257 Docstring Conventions. It produces messages for any divergence from the style guide.

This tool is currently considered experimental due to some bugs in its ability to parse code. For example, modules that contain an __all__ could end up producing bogus error messages if the __all__ isn’t formatted exactly as pydocstyle expects it.

It will not run by default, and must be enabled explicitly (via --with-tool pep257 or in a profile) or implicitly (using the --doc-warnings flag).

profile-validator

This is a simple tool built in to prospector which validates prospector profiles.

Optional Extras

These extras are integrated into prospector but are not activated by default. This is because their output is not necessarily useful for all projects.

They are also not installed by default. The instructions for installing each tool is in the tool section below. To install all extras at the same time, install prospector using the with_everything option:

pip install prospector[with_everything]

Pyroma

Pyroma is a tool to check your setup.py to ensure it is following best practices of the Python packaging ecosystem. It will warn you if you are missing any package metadata which would improve the quality of your package. This is recommended if you intend to publish your code on PyPI.

To install and use:

pip install prospector[with_pyroma]
prospector --with-tool pyroma

Vulture

Vulture finds unused classes, functions and variables in your code. This could be useful if your project is an application rather than a library, however, if you do a lot of dynamic access or metaprogramming, Vulture will likely warn about unused code that is in fact used.

To install and use:

pip install prospector[with_vulture]
prospector --with-tool vulture

frosted

Frosted is a fork of pyflakes which was created with the intention of taking over from and extending pyflakes as development had slowed. Since Prospector was originally created, pyflakes development has started up again and frosted has stagnated, so it has been demoted to be an optional extra.

To install and use:

pip install prospector[with_frosted]
prospector --with-tool frosted