vulture 2.14
Find dead code
License: MIT
Requires Python: >=3.8
Keywords: dead-code-removal

# Vulture - Find dead code

[![PyPI Version](https://img.shields.io/pypi/v/vulture.svg)](https://pypi.python.org/pypi/vulture)
[![Conda Version](https://img.shields.io/conda/vn/conda-forge/vulture.svg)](https://anaconda.org/conda-forge/vulture)
![CI:Test](https://github.com/jendrikseipp/vulture/workflows/CI/badge.svg)
[![Codecov Badge](https://codecov.io/gh/jendrikseipp/vulture/branch/main/graphs/badge.svg)](https://codecov.io/gh/jendrikseipp/vulture?branch=main)

Vulture finds unused code in Python programs. This is useful for
cleaning up and finding errors in large code bases. If you run Vulture
on both your library and test suite you can find untested code.

Due to Python's dynamic nature, static code analyzers like Vulture are
likely to miss some dead code. Also, code that is only called implicitly
may be reported as unused. Nonetheless, Vulture can be a very helpful
tool for higher code quality.

## Features

* fast: uses static code analysis
* tested: tests itself and has complete test coverage
* complements pyflakes and has the same output syntax
* sorts unused classes and functions by size with `--sort-by-size`

## Installation

    $ pip install vulture

## Usage

    $ vulture myscript.py  # or
    $ python3 -m vulture myscript.py
    $ vulture myscript.py mypackage/
    $ vulture myscript.py --min-confidence 100  # Only report 100% dead code.

The provided arguments may be Python files or directories. For each
directory Vulture analyzes all contained
<span class="title-ref">\*.py</span> files.

After you have found and deleted dead code, run Vulture again, because
it may discover more dead code.

## Types of unused code

In addition to finding unused functions, classes, etc., Vulture can detect
unreachable code. Each chunk of dead code is assigned a *confidence value*
between 60% and 100%, where a value of 100% signals that it is certain that the
code won't be executed. Values below 100% are *very rough* estimates (based on
the type of code chunk) for how likely it is that the code is unused.

| Code type | Confidence value |
| ------------------- | -- |
| function/method/class argument, unreachable code | 100% |
| import | 90% |
| attribute, class, function, method, property, variable | 60% |

You can use the `--min-confidence` flag to set the minimum confidence
for code to be reported as unused. Use `--min-confidence 100` to only
report code that is guaranteed to be unused within the analyzed files.

## Handling false positives

When Vulture incorrectly reports chunks of code as unused, you have
several options for suppressing the false positives. If fixing your false
positives could benefit other users as well, please file an issue report.

#### Whitelists

The recommended option is to add used code that is reported as unused to a
Python module and add it to the list of scanned paths. To obtain such a
whitelist automatically, pass `--make-whitelist` to Vulture:

    $ vulture mydir --make-whitelist > whitelist.py
    $ vulture mydir whitelist.py

Note that the resulting `whitelist.py` file will contain valid Python
syntax, but for Python to be able to *run* it, you will usually have to
make some modifications.

We collect whitelists for common Python modules and packages in
`vulture/whitelists/` (pull requests are welcome).

#### Ignoring files

If you want to ignore a whole file or directory, use the `--exclude` parameter
(e.g., `--exclude "*settings.py,*/docs/*.py,*/test_*.py,*/.venv/*.py"`). The
exclude patterns are matched against absolute paths.

#### Flake8 noqa comments

<!-- Hide noqa docs until we decide whether we want to support it.
Another way of ignoring errors is to annotate the line causing the false
positive with `# noqa: <ERROR_CODE>` in a trailing comment (e.g., `#
noqa: V103`). The `ERROR_CODE` specifies what kind of dead code to
ignore (see the table below for the list of error codes). In case no
error code is specified, Vulture ignores all results for the line.
(Note that the line number for decorated objects is the line number of
the first decorator.)
-->

For compatibility with [flake8](https://flake8.pycqa.org/), Vulture
supports the [F401 and
F841](https://flake8.pycqa.org/en/latest/user/error-codes.html) error
codes for ignoring unused imports (`# noqa: F401`) and unused local
variables (`# noqa: F841`). However, we recommend using whitelists instead
of `noqa` comments, since `noqa` comments add visual noise to the code and
make it harder to read.

#### Ignoring names

You can use `--ignore-names foo*,ba[rz]` to let Vulture ignore all names
starting with `foo` and the names `bar` and `baz`. Additionally, the
`--ignore-decorators` option can be used to ignore the names of functions
decorated with the given decorator (but not their arguments or function body).
This is helpful for example in Flask
projects, where you can use `--ignore-decorators "@app.route"` to ignore all
function names with the `@app.route` decorator. Note that Vulture simplifies
decorators it cannot parse: `@foo.bar(x, y)` becomes "@foo.bar" and
`@foo.bar(x, y).baz` becomes "@" internally.

We recommend using whitelists instead of `--ignore-names` or
`--ignore-decorators` whenever possible, since whitelists are
automatically checked for syntactic correctness when passed to Vulture
and often you can even pass them to your Python interpreter and let it
check that all whitelisted code actually still exists in your project.

#### Marking unused variables

There are situations where you can't just remove unused variables, e.g.,
in function signatures. The recommended solution is to use the `del`
keyword as described in the
[PyLint manual](http://pylint-messages.wikidot.com/messages:w0613) and on
[StackOverflow](https://stackoverflow.com/a/14836005):

```python
def foo(x, y):
    del y
    return x + 3
```

Vulture will also ignore all variables that start with an underscore, so
you can use `_x, y = get_pos()` to mark unused tuple assignments or
function arguments, e.g., `def foo(x, _y)`.

#### Minimum confidence

Raise the minimum [confidence value](#types-of-unused-code) with the `--min-confidence` flag.

#### Unreachable code

If Vulture complains about code like `if False:`, you can use a Boolean
flag `debug = False` and write `if debug:` instead. This makes the code
more readable and silences Vulture.

#### Forward references for type annotations

See [#216](https://github.com/jendrikseipp/vulture/issues/216). For
example, instead of `def foo(arg: "Sequence"): ...`, we recommend using

``` python
from __future__ import annotations

def foo(arg: Sequence):
    ...
```


## Configuration

You can also store command line arguments in `pyproject.toml` under the
`tool.vulture` section. Simply remove leading dashes and replace all
remaining dashes with underscores.

Options given on the command line have precedence over options in
`pyproject.toml`.

Example Config:

``` toml
[tool.vulture]
exclude = ["*file*.py", "dir/"]
ignore_decorators = ["@app.route", "@require_*"]
ignore_names = ["visit_*", "do_*"]
make_whitelist = true
min_confidence = 80
paths = ["myscript.py", "mydir", "whitelist.py"]
sort_by_size = true
verbose = true
```

Vulture will automatically look for a `pyproject.toml` in the current working directory.

To use a `pyproject.toml` in another directory, you can use the `--config path/to/pyproject.toml` flag.

## Integrations

You can use a [pre-commit](https://pre-commit.com/#install) hook to run
Vulture before each commit. For this, install pre-commit and add the
following to the `.pre-commit-config.yaml` file in your repository:

```yaml
repos:
  - repo: https://github.com/jendrikseipp/vulture
    rev: 'v2.3'  # or any later Vulture version
    hooks:
      - id: vulture
```

Then run `pre-commit install`. Finally, create a `pyproject.toml` file
in your repository and specify all files that Vulture should check under
`[tool.vulture] --> paths` (see above).

There's also a [GitHub Action for Vulture](https://github.com/gtkacz/vulture-action)
and you can use Vulture programatically. For example:

``` python
import vulture

v = vulture.Vulture()
v.scavenge(['.'])
unused_code = v.get_unused_code()  # returns a list of `Item` objects
```

## How does it work?

Vulture uses the `ast` module to build abstract syntax trees for all
given files. While traversing all syntax trees it records the names of
defined and used objects. Afterwards, it reports the objects which have
been defined, but not used. This analysis ignores scopes and only takes
object names into account.

Vulture also detects unreachable code by looking for code after
`return`, `break`, `continue` and `raise` statements, and by searching
for unsatisfiable `if`- and `while`-conditions.

## Sort by size

When using the `--sort-by-size` option, Vulture sorts unused code by its
number of lines. This helps developers prioritize where to look for dead
code first.

## Examples

Consider the following Python script (`dead_code.py`):

``` python
import os

class Greeter:
    def greet(self):
        print("Hi")

def hello_world():
    message = "Hello, world!"
    greeter = Greeter()
    func_name = "greet"
    greet_func = getattr(greeter, func_name)
    greet_func()

if __name__ == "__main__":
    hello_world()
```

Calling :

    $ vulture dead_code.py

results in the following output:

    dead_code.py:1: unused import 'os' (90% confidence)
    dead_code.py:4: unused function 'greet' (60% confidence)
    dead_code.py:8: unused variable 'message' (60% confidence)

Vulture correctly reports `os` and `message` as unused but it fails to
detect that `greet` is actually used. The recommended method to deal
with false positives like this is to create a whitelist Python file.

**Preparing whitelists**

In a whitelist we simulate the usage of variables, attributes, etc. For
the program above, a whitelist could look as follows:

``` python
# whitelist_dead_code.py
from dead_code import Greeter
Greeter.greet
```

Alternatively, you can pass `--make-whitelist` to Vulture and obtain an
automatically generated whitelist.

Passing both the original program and the whitelist to Vulture

    $ vulture dead_code.py whitelist_dead_code.py

makes Vulture ignore the `greet` method:

    dead_code.py:1: unused import 'os' (90% confidence)
    dead_code.py:8: unused variable 'message' (60% confidence)

<!-- Hide noqa docs until we decide whether we want to support it.
**Using "# noqa"**

```python
import os  # noqa

class Greeter:  # noqa: V102
    def greet(self):  # noqa: V103
        print("Hi")
```

## Error codes

For compatibility with [flake8](https://flake8.pycqa.org/), Vulture
supports the [F401 and
F841](https://flake8.pycqa.org/en/latest/user/error-codes.html) error
codes.

| Error codes |    Description    |
| ----------- | ----------------- |
| V101        | Unused attribute  |
| V102        | Unused class      |
| V103        | Unused function   |
| V104, F401  | Unused import     |
| V105        | Unused property   |
| V106        | Unused method     |
| V107, F841  | Unused variable   |
| V201        | Unreachable code  |

-->

## Exit codes

| Exit code |                          Description                          |
| --------- | ------------------------------------------------------------- |
|     0     | No dead code found                                            |
|     1     | Invalid input (file missing, syntax error, wrong encoding)    |
|     2     | Invalid command line arguments                                |
|     3     | Dead code found                                               |

## Similar programs

  - [pyflakes](https://pypi.org/project/pyflakes/) finds unused imports
    and unused local variables (in addition to many other programmatic
    errors).
  - [coverage](https://pypi.org/project/coverage/) finds unused code
    more reliably than Vulture, but requires all branches of the code to
    actually be run.
  - [uncalled](https://pypi.org/project/uncalled/) finds dead code by
    using the abstract syntax tree (like Vulture), regular expressions,
    or both.
  - [dead](https://pypi.org/project/dead/) finds dead code by using the
    abstract syntax tree (like Vulture).

## Participate

Please visit <https://github.com/jendrikseipp/vulture> to report any
issues or to make pull requests.

  - Contributing guide:
    [CONTRIBUTING.md](https://github.com/jendrikseipp/vulture/blob/main/CONTRIBUTING.md)
  - Release notes:
    [CHANGELOG.md](https://github.com/jendrikseipp/vulture/blob/main/CHANGELOG.md)
  - Roadmap:
    [TODO.md](https://github.com/jendrikseipp/vulture/blob/main/TODO.md)


# 2.14 (2024-12-08)

* Improve reachability analysis (kreathon, #270, #302).
* Add type hints for `get_unused_code` and the fields of the `Item` class (John Doknjas, #361).

# 2.13 (2024-10-02)

* Add support for Python 3.13 (Jendrik Seipp, #369).
* Add PyPI and conda-forge badges to README file (Trevor James Smith, #356).
* Include `tests/**/*.toml` in sdist (Colin Watson).

# 2.12 (2024-09-17)

* Use `ruff` for linting and formatting (Anh Trinh, #347, #349).
* Replace `tox` by `pre-commit` for linting and formatting (Anh Trinh, #349).
* Add `--config` flag to specify path to pyproject.toml configuration file (Glen Robertson, #352).

# 2.11 (2024-01-06)

* Switch to tomllib/tomli to support heterogeneous arrays (Sebastian Csar, #340).
* Bump flake8, flake8-comprehensions and flake8-bugbear (Sebastian Csar, #341).
* Provide whitelist parity for `MagicMock` and `Mock` (maxrake, #342).

# 2.10 (2023-10-06)

* Drop support for Python 3.7 (Jendrik Seipp, #323).
* Add support for Python 3.12 (Jendrik Seipp, #332).
* Use `end_lineno` AST attribute to obtain more accurate line counts (Jendrik Seipp).

# 2.9.1 (2023-08-21)

* Use exit code 0 for `--help` and `--version` again (Jendrik Seipp, #321).

# 2.9 (2023-08-20)

* Use exit code 3 when dead code is found (whosayn, #319).
* Treat non-supported decorator names as "@" instead of crashing (Llandy3d and Jendrik Seipp, #284).
* Drop support for Python 3.6 (Jendrik Seipp).

# 2.8 (2023-08-10)

* Add `UnicodeEncodeError` exception handling to `core.py` (milanbalazs, #299).
* Add whitelist for `Enum` attributes `_name_` and `_value_` (Eugene Toder, #305).
* Run tests and add PyPI trove for Python 3.11 (Jendrik Seipp).

# 2.7 (2023-01-08)

* Ignore `setup_module()`, `teardown_module()`, etc. in pytest `test_*.py` files (Jendrik Seipp).
* Add whitelist for `socketserver.TCPServer.allow_reuse_address` (Ben Elliston).
* Clarify that `--exclude` patterns are matched against absolute paths (Jendrik Seipp, #260).
* Fix example in README file (Jendrik Seipp, #272).

# 2.6 (2022-09-19)

* Add basic `match` statement support (kreathon, #276, #291).

# 2.5 (2022-07-03)

* Mark imports in `__all__` as used (kreathon, #172, #282).
* Add whitelist for `pint.UnitRegistry.default_formatter` (Ben Elliston, #258).

# 2.4 (2022-05-19)

* Print absolute filepaths as relative again (as in version 2.1 and before)
  if they are below the current directory (The-Compiler, #246).
* Run tests and add PyPI trove for Python 3.10 (chayim, #266).
* Allow using the `del` keyword to mark unused variables (sshishov, #279).

# 2.3 (2021-01-16)

* Add [pre-commit](https://pre-commit.com) hook (Clément Robert, #244).

# 2.2 (2021-01-15)

* Only parse format strings when being used with `locals()` (jingw, #225).
* Don't override paths in pyproject.toml with empty CLI paths (bcbnz, #228).
* Run continuous integration tests for Python 3.9 (ju-sh, #232).
* Use pathlib internally (ju-sh, #226).

# 2.1 (2020-08-19)

* Treat `getattr/hasattr(obj, "constant_string", ...)` as a reference to
  `obj.constant_string` (jingw, #219).
* Fix false positives when assigning to `x.some_name` but reading via
  `some_name`, at the cost of potential false negatives (jingw, #221).
* Allow reading options from `pyproject.toml` (Michel Albert, #164, #215).

# 2.0 (2020-08-11)

* Parse `# type: ...` comments if on Python 3.8+ (jingw, #220).
* Bump minimum Python version to 3.6 (Jendrik Seipp, #218). The last
  Vulture release that supports Python 2.7 and Python 3.5 is version 1.6.
* Consider all files under `test` or `tests` directories test files
  (Jendrik Seipp).
* Ignore `logging.Logger.propagate` attribute (Jendrik Seipp).

# 1.6 (2020-07-28)

* Differentiate between functions and methods (Jendrik Seipp, #112, #209).
* Move from Travis to GitHub actions (RJ722, #211).

# 1.5 (2020-05-24)

* Support flake8 "noqa" error codes F401 (unused import) and F841 (unused
  local variable) (RJ722, #195).
* Detect unreachable code in conditional expressions
  (Agathiyan Bragadeesh, #178).

# 1.4 (2020-03-30)

* Ignore unused import statements in `__init__.py` (RJ722, #192).
* Report first decorator's line number for unused decorated objects on
  Python 3.8+ (RJ722, #200).
* Check code with black and pyupgrade.

# 1.3 (2020-02-03)

* Detect redundant 'if' conditions without 'else' blocks.
* Add whitelist for `string.Formatter` (Joseph Bylund, #183).

# 1.2 (2019-11-22)

* Fix tests for Python 3.8 (#166).
* Use new `Constant` AST node under Python 3.8+ (#175).
* Add test for f-strings (#177).
* Add whitelist for `logging` module.

# 1.1 (2019-09-23)

* Add `sys.excepthook` to `sys` whitelist.
* Add whitelist for `ctypes` module.
* Check that type annotations are parsed and type comments are ignored
  (thanks @kx-chen).
* Support checking files with BOM under Python 2.7 (#170).

# 1.0 (2018-10-23)

* Add `--ignore-decorators` flag (thanks @RJ722).
* Add whitelist for `threading` module (thanks @andrewhalle).

# 0.29 (2018-07-31)

* Add `--ignore-names` flag for ignoring names matching the given glob
  patterns (thanks @RJ722).

# 0.28 (2018-07-05)

* Add `--make-whitelist` flag for reporting output in whitelist format
  (thanks @RJ722).
* Ignore case of `--exclude` arguments on Windows.
* Add `*-test.py` to recognized test file patterns.
* Add `failureException`, `longMessage` and `maxDiff` to `unittest`
  whitelist.
* Refer to actual objects rather than their mocks in default
  whitelists (thanks @RJ722).
* Don't import any Vulture modules in setup.py (thanks @RJ722).

# 0.27 (2018-06-05)

* Report `while (True): ... else: ...` as unreachable (thanks @RJ722).
* Use `argparse` instead of `optparse`.
* Whitelist Mock.return\_value and Mock.side\_effect in unittest.mock
  module.
* Drop support for Python 2.6 and 3.3.
* Improve documentation and test coverage (thanks @RJ722).

# 0.26 (2017-08-28)

* Detect `async` function definitions (thanks @RJ722).
* Add `Item.get_report()` method (thanks @RJ722).
* Move method for finding Python modules out of Vulture class.

# 0.25 (2017-08-15)

* Detect unsatisfiable statements containing `and`, `or` and `not`.
* Use filenames and line numbers as tie-breakers when sorting by size.
* Store first and last line numbers in Item objects.
* Pass relevant options directly to `scavenge()` and `report()`.

# 0.24 (2017-08-14)

* Detect unsatisfiable `while`-conditions (thanks @RJ722).
* Detect unsatisfiable `if`- and `else`-conditions (thanks @RJ722).
* Handle null bytes in source code.

# 0.23 (2017-08-10)

* Add `--min-confidence` flag (thanks @RJ722).

# 0.22 (2017-08-04)

* Detect unreachable code after `return`, `break`, `continue` and
  `raise` (thanks @RJ722).
* Parse all variable and attribute names in new format strings.
* Extend ast whitelist.

# 0.21 (2017-07-26)

* If an unused item is defined multiple times, report it multiple
  times.
* Make size estimates for function calls more accurate.
* Create wheel files for Vulture (thanks @RJ722).

# 0.20 (2017-07-26)

* Report unused tuple assignments as dead code.
* Report attribute names that have the same names as variables as dead
  code.
* Let Item class inherit from `object` (thanks @RJ722).
* Handle names imported as aliases like all other used variable names.
* Rename Vulture.used\_vars to Vulture.used\_names.
* Use function for determining which imports to ignore.
* Only try to import each whitelist file once.
* Store used names and used attributes in sets instead of lists.
* Fix estimating the size of code containing ellipses (...).
* Refactor and simplify code.

# 0.19 (2017-07-20)

* Don't ignore <span class="title-ref">\_\_foo</span> variable names.
* Use separate methods for determining whether to ignore classes and
  functions.
* Only try to find a whitelist for each defined import once (thanks
  @roivanov).
* Fix finding the last child for many types of AST nodes.

# 0.18 (2017-07-17)

* Make <span class="title-ref">--sort-by-size</span> faster and more
  accurate (thanks @RJ722).

# 0.17 (2017-07-17)

* Add <span class="title-ref">get\_unused\_code()</span> method.
* Return with exit code 1 when syntax errors are found or files can't
  be read.

# 0.16 (2017-07-12)

* Differentiate between unused classes and functions (thanks @RJ722).
* Add --sort-by-size option (thanks @jackric and @RJ722).
* Count imports as used if they are accessed as module attributes.

# 0.15 (2017-07-04)

* Automatically include whitelists based on imported modules (thanks
  @RJ722).
* Add --version parameter (thanks @RJ722).
* Add appveyor tests for testing on Windows (thanks @RJ722).

# 0.14 (2017-04-06)

* Add stub whitelist file for Python standard library (thanks @RJ722)
* Ignore class names starting with "Test" in "test\_" files (thanks
  @thisch).
* Ignore "test\_" functions only in "test\_" files.

# 0.13 (2017-03-06)

* Ignore star-imported names since we cannot detect whether they are
  used.
* Move repository to GitHub.

# 0.12 (2017-01-05)

* Detect unused imports.
* Use tokenize.open() on Python \>= 3.2 for reading input files,
  assume UTF-8 encoding on older Python versions.

# 0.11 (2016-11-27)

* Use the system's default encoding when reading files.
* Report syntax errors instead of aborting.

# 0.10 (2016-07-14)

* Detect unused function and method arguments (issue #15).
* Detect unused \*args and \*\*kwargs parameters.
* Change license from GPL to MIT.

# 0.9 (2016-06-29)

* Don't flag attributes as unused if they are used as global variables
  in another module (thanks Florian Bruhin).
* Don't consider "True" and "False" variable names.
* Abort with error message when invoked on .pyc files.

# 0.8.1 (2015-09-28)

* Fix code for Python 3.

# 0.8 (2015-09-28)

* Do not flag names imported with "import as" as dead code (thanks Tom
  Terrace).

# 0.7 (2015-09-26)

* Exit with exitcode 1 if path on commandline can't be found.
* Test vulture with vulture using a whitelist module for false
  positives.
* Add tests that run vulture as a script.
* Add "python setup.py test" command for running tests.
* Add support for tox.
* Raise test coverage to 100%.
* Remove ez\_setup.py.

# 0.6 (2014-09-06)

* Ignore function names starting with "test\_".
* Parse variable names in new format strings (e.g. "This is
  {x}".format(x="nice")).
* Only parse alphanumeric variable names in format strings and ignore
  types.
* Abort with exit code 1 on syntax errors.
* Support installation under Windows by using setuptools (thanks
  Reuben Fletcher-Costin).

# 0.5 (2014-05-09)

* If dead code is found, exit with 1.

# 0.4.1 (2013-09-17)

* Only warn if a path given on the command line cannot be found.

# 0.4 (2013-06-23)

* Ignore unused variables starting with an underscore.
* Show warning for syntax errors instead of aborting directly.
* Print warning if a file cannot be found.

# 0.3 (2012-03-19)

* Add support for python3
* Report unused attributes
* Find tuple assignments in comprehensions
* Scan files given on the command line even if they don't end with .py

# 0.2 (2012-03-18)

* Only format nodes in verbose mode (gives 4x speedup).

# 0.1 (2012-03-17)

* First release.