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dead simple python dead code detection

License: MIT License

Python 100.00%

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afonasev sandy4321 mxr morristech bagerard admdev8 pmbarrett314 rsabet jay2109 petergaultney dorschw

dead's Issues

Run pre-commit-hook only on files to be committed

Is there a way to run the dead pre-commit-hook only on files to be committed? Otherwise it runs on all files (e.g. not staged for commit)

treat names in `all` as un-dead

Detect unused arguments

A related feature that could be useful would be to detect "dead arguments," or function arguments not used by the function body.

Here is an example of a dead argument found in pip: pypa/pip#7015

importing a symbol without using it marks it as used

# foo.py
def foo(): ...

# bar.py
from foo import foo # Imported but unused

$ dead
# Dead silence, even if you commit foo.py and bar.py

From what I've looked this seems like intended behavior - why? is there a false positive corner case I'm missing?
https://github.com/asottile/dead/blob/master/dead.py#L50
And if it is intended I'd like a configuration value to change it

Add a better interface for only checking specific files in a larger codebase

As always, thanks for the tools! ❤️

I use dead on a small number of files in a larger codebase, and have it integrated via pre-commit. We're only using dead where we consider it particularly helpful.

Right now, this means that we have a config in pre-commit like so:

- repo: https://github.com/asottile/dead
  rev: v1.4.0
  hooks:
    - id: dead
      args:
        - "--files"
        - |
          (?x)(
            src/project/component1/foo.py|
            src/project/component1/bar/baz.py|
            src/project/component2/spam.py
          )

This feels awkward as the list grows. Plus, it reports things inaccurately if they're used in a module which I don't want covered by dead.

I'm trying to work out the right approach. It would be really cool to have dead read the full codebase as it does by default, but only report failures in the target files.
e.g.

      args:
       # `--check-files` or `--report-files` or `--only` or some other name is fine
        - "--report-files"
        - "src/project/component1/foo.py"
        - "src/project/component1/bar/baz.py"
        - "src/project/component2/spam.py"

I'm more than happy to try to contribute a patch if this would be acceptable. I don't want to bloat things. I think just a filter at the very end, when output and the exit code are being handled, to see if the passed --report-files matches files before treating them as failures.

Does this sound interesting as a feature?

dead raises ValueError in case a file is deleted (since it remains listed with "git ls-files")

Hi,
Just hit this twice in a week. I'm using dead to clean up a large codebase and realized that as soon as you delete a file, dead starts complaining that it can't find that same file in subsequent run

Traceback (most recent call last):
  File "/home/***/.pyenv/versions/3.6.5/envs/cmp/bin/dead", line 8, in <module>
    sys.exit(main())
  File "/home/***/.pyenv/versions/3.6.5/envs/cmp/lib/python3.6/site-packages/dead.py", line 302, in main
    for filename, is_test in _filenames(files_re, exclude_re, tests_re):
  File "/home/***/.pyenv/versions/3.6.5/envs/cmp/lib/python3.6/site-packages/dead.py", line 213, in _filenames
    'python' not in tags_from_path(filename)
  File "/home/***/.pyenv/versions/3.6.5/envs/cmp/lib/python3.6/site-packages/identify/identify.py", line 38, in tags_from_path
    raise ValueError('{} does not exist.'.format(path))
ValueError: myapp/lib/helpers.py does not exist.

I quickly check and the problem is that it relies on git ls-files, which lists also the deleted files.
The workaround is to commit the change, then re-execute dead but I thought it is worth fixing this.

I havn't seen an option in git ls-files to lists everything except the deleted file but I see that I can list the deleted files with git ls-files --deleted so I guess we can use that to subtract the deleted files.

Let me know your thoughts and if that seems like a good approach, I'd be happy to implement it.

pre-commit hook does not work

Config:

  - repo: https://github.com/asottile/dead
    rev: ''
    hooks:
      - id: dead

Output:

detect dead code.........................................................Failed
hookid: dead

usage: dead [-h] [--files FILES] [--exclude EXCLUDE] [--tests TESTS]
dead: error: unrecognized arguments: tests/helpers/pkg/circles/simple_class.py src/_dependencies/checks/operation.py tests/helpers/examples/operation.py src/dependencies/contrib/django.py src/_dependencies/operation.py tests/helpers/pkg/injected.py tests/helpers/pkg/submodule.py src/_dependencies/markers.py tests/helpers/examples/order/commands.py tests/helpers/examples/users/__init__.py tests/test_contrib_django.py tests/helpers/pkg/circles/__init__.py src/dependencies/contrib/flask.py tests/helpers/django_project/__init__.py src/_dependencies/checks/__init__.py tests/helpers/helpers.py tests/test_contrib_flask.py tests/test_contrib_rest_framework.py tests/helpers/flask_project/__init__.py src/_dependencies/injector.py tests/helpers/examples/order/tasks.py src/_dependencies/attributes.py src/_dependencies/func.py src/_dependencies/checks/value.py src/dependencies/contrib/__init__.py tests/test_injector.py src/_dependencies/contrib/django.py tests/test_package.py
usage: dead [-h] [--files FILES] [--exclude EXCLUDE] [--tests TESTS]
dead: error: unrecognized arguments: tests/helpers/examples/cart/serializers.py src/dependencies/contrib/celery.py src/_dependencies/spec.py tests/helpers/pkg/circles/complex_operation.py tests/helpers/examples/cart/commands.py tests/helpers/examples/stubs.py tests/helpers/examples/overview.py tests/helpers/pkg/circles/long_value.py tests/helpers/examples/cart/views.py tests/helpers/django_project/api/throttle.py tests/helpers/django_project/api/exceptions.py tests/helpers/django_project/api/version.py tests/helpers/pkg/self_pointer.py tests/helpers/django_project/api/__init__.py src/_dependencies/checks/func.py tests/helpers/pkg/circles/simple_value.py tests/test_contrib_rest_framework_generic_view_set.py src/_dependencies/checks/this.py tests/helpers/flask_project/app.py tests/helpers/examples/cart/filtersets.py tests/helpers/django_project/commands.py tests/test_operation.py tests/helpers/examples/faq.py tests/test_checks_loops.py tests/helpers/flask_project/commands.py tests/helpers/pkg/__init__.py tests/helpers/django_project/api/negotiation.py src/_dependencies/contrib/rest_framework.py
usage: dead [-h] [--files FILES] [--exclude EXCLUDE] [--tests TESTS]
dead: error: unrecognized arguments: tests/helpers/mddoctest.py tests/helpers/django_project/urls.py tests/helpers/django_project/api/urls.py tests/helpers/django_project/api/metadata.py tests/test_value.py src/_dependencies/raw.py tests/helpers/examples/utils.py tests/helpers/django_project/api/auth.py src/_dependencies/classes.py tests/helpers/django_project/api/commands.py tests/helpers/django_project/api/filtersets.py src/_dependencies/__init__.py tests/helpers/flask_project/views.py tests/helpers/django_project/settings.py src/_dependencies/value.py src/dependencies/contrib/rest_framework.py src/dependencies/contrib/pytest.py tests/helpers/django_project/forms.py src/_dependencies/contrib/celery.py tests/helpers/django_project/api/serializers.py tests/helpers/django_project/apps.py src/_dependencies/contrib/flask.py tests/helpers/pkg/circles/long_operation.py tests/helpers/examples/cart/forms.py tests/helpers/examples/order/__init__.py tests/helpers/examples/users/utils.py tests/test_nested.py src/_dependencies/this.py
usage: dead [-h] [--files FILES] [--exclude EXCLUDE] [--tests TESTS]
dead: error: unrecognized arguments: tests/helpers/examples/__init__.py src/_dependencies/exceptions.py tests/helpers/pkg/circles/complex_value.py src/_dependencies/checks/injector.py src/_dependencies/checks/loops.py src/dependencies/__init__.py tests/test_contrib_pytest.py src/_dependencies/contrib/pytest.py tests/helpers/django_project/api/views.py tests/helpers/django_project/views.py tests/test_configuration.py tests/helpers/pkg/circles/long_class.py src/dependencies/exceptions.py tests/test_this.py tests/helpers/pkg/circles/complex_class.py src/_dependencies/contrib/__init__.py src/_dependencies/nested.py tests/helpers/examples/cart/models.py src/_dependencies/package.py tests/helpers/examples/cart/__init__.py tests/test_contrib_celery.py tests/test_checks_circles.py tests/helpers/pkg/circles/simple_operation.py src/_dependencies/replace.py src/_dependencies/checks/circles.py tests/test_contrib_rest_framework_view_set.py

Add option to allowlist decorated functions as un-dead

Certain decorators like Flask.route point to usage from some external code or framework.
I'd like the ability to create a per-project whitelist (maybe with some common defaults) of such decorators to reduce the number of false positives

Django support

So it might be rather difficult to do, and i get the "i wrote it on an airplane" - but i like the idea of the code. However it doesn't really work with Django (i got a million deadcode things like my settings constants etc)

separate "non-dead" annotations from the code

We have a lot of dead code that this tool catches beautifully. Thank you!

We also have a lot of not-actually-dead code, or "yes technically that's dead but there's a good reason why it's there".

Unfortunately, I don't have the stomach for adding # dead: disable to all the places where this is the case. It would be a lot of changes that would make the code harder to read.

Would you be open to supporting as an input a "ignore_filelines" file? I'm thinking newline separated, in exactly the format you already use (fully/qualified/filename.py:<linum>), that would essentially pre-populate visitor.disabled (probably right after construction: https://github.com/asottile/dead/blob/main/dead.py#L310)?

This would let me keep our code separate from our linting. I think it would pretty much 'just' work, but I haven't fully grokked your code.

Let me know - if so, I'd like to make a PR and get this working!

Question: Do I need dead if I use a code coverage tool?

Are there any cases dead can detect dead code, which for example codecov can't?

Global pre-commit exclude does not work for dead

The global option exclude does not work for the dead hook.

exclude: "..."
repos:
  - repo: ...

To workaround this I exclude for this hook additionally:

  - repo: https://github.com/asottile/dead
    rev: v1.4.0
    hooks:
      - id: dead
        args: ["--exclude", "..."]

Does not recognize PEP 484 type comments as "used"

can probably take inspiration from PyCQA/pyflakes#400

here's a small example

X = str

def s():  # type: () -> X
    return 'hi'

Crash caused by certain # type: ignore statements

It appears that dead can't handle code that uses MyPy error codes in type: ignore directives.

To reproduce:

def foo() -> int:
    return None  # type: ignore[no-any-return]

Run dead with no arguments:

dargueta@tux ~/blah (master)$ dead           
Traceback (most recent call last):
  File "/Users/dargueta/.pyenv/versions/3.8.6/bin/dead", line 8, in <module>
    sys.exit(main())
  File "/Users/dargueta/.pyenv/versions/3.8.6/lib/python3.8/site-packages/dead.py", line 314, in main
    visitor.visit_comment(lineno, s)
  File "/Users/dargueta/.pyenv/versions/3.8.6/lib/python3.8/site-packages/dead.py", line 195, in visit_comment
    ast_obj = ast.parse(part, f'<{self.filename}:{lineno}: comment>')
  File "/Users/dargueta/.pyenv/versions/3.8.6/lib/python3.8/ast.py", line 47, in parse
    return compile(source, filename, mode, flags,
  File "<blah.py:2: comment>", line 1
    ignore[no-any-return]
                  ^
SyntaxError: invalid syntax

The problem is in the TYPE_IGNORE_RE regex. The visit_comment() function ignores these type: ignore comments, but the regex doesn't match type: ignore[xyz], only type: ignore. I recommend changing the regex to:

TYPE_COMMENT_RE.pattern + r'ignore\s*(\[[\w-]+\]\s*)?(#|$)'
#                                    ^^^^^^^^^^^^^^^^
#                                    insert this

Environment:

Python: 3.7.6, 3.8.6
Operating System: MacOS 11.1 (Big Sur)
dead version: 1.3.0

Add support for `getattr` calls

For example running dead on itself yields

visit_ImportFrom is never read, defined in {'dead.py'}
visit_ClassDef is never read, defined in {'dead.py'}
visit_AsyncFunctionDef is never read, defined in {'dead.py'}
visit_Assign is never read, defined in {'dead.py'}
visit_Name is never read, defined in {'dead.py'}
visit_Attribute is never read, defined in {'dead.py'}
visit_Str is never read, defined in {'dead.py'}

Even though they are all read by NodeVisitor.visit
https://github.com/python/cpython/blob/master/Lib/ast.py#L250-253

Unused parameters from framework

Hi,
I use a framework that uses callbacks with some parameters I do not need in some cases. dead always shows them as unused (and they are). Would it be possible to have a solution like pylint has to avoid dead reporting them?

From pylint docs:

# fix for positional arguments: prepend _
def example1(_foo):
    return 1

# fix for keyword args: catch into _
def example2(used_kw_arg=1, **_):
    return used_kw_arg + 1

# fix for a single keyword arg: delete it
def example2(used_kw_arg=1, another_kw_arg=2):
    del another_kw_arg
    return used_kw_arg + 1

I tried the first and last solution with dead and it still reports the parameters.

Best regards

Traceback (most recent call last):
  File "/home/canalejas/.cache/pre-commit/repo05xoyxeg/py_env-python3/bin/dead", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/home/canalejas/.cache/pre-commit/repo05xoyxeg/py_env-python3/lib/python3.11/site-packages/dead.py", line 319, in main
    tree = _ast(filename)
           ^^^^^^^^^^^^^^
  File "/home/canalejas/.cache/pre-commit/repo05xoyxeg/py_env-python3/lib/python3.11/site-packages/dead.py", line 236, in _ast
    return ast.parse(f.read(), filename=filename)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/ast.py", line 50, in parse
    return compile(source, filename, mode, flags,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "apps/actions/management/helpers/input.py", line 56
    def _input_competition[T: Trophy | Flag](_model: type[T], name: str) -> tuple[T | None, int | None]:
                          ^
SyntaxError: expected '('