Add DEP005 to detect dependencies that are in the standard library

docs/rules-violations.md

@@ -8,6 +8,7 @@ _deptry_ checks your project against the following rules related to dependencies
 | DEP002 | Project should not contain unused dependencies               | [link](#unused-dependencies-dep002)                 |
 | DEP003 | Project should not use transitive dependencies            | [link](#transitive-dependencies-dep003)             |
 | DEP004 | Project should not use development dependencies in non-development code | [link](#misplaced-development-dependencies-dep004)  |
+| DEP005 | Project should not contain dependencies that are in the standard library    | [link](#standard-library-dependencies-dep005)       |
 
 Any of the checks can be disabled with the [`ignore`](usage.md#ignore) flag. Specific dependencies or modules can be
 ignored with the [`per-rule-ignores`](usage.md#per-rule-ignores) flag.
@@ -170,3 +171,36 @@ dependencies = [
 [tool.pdm.dev-dependencies]
 test = ["pytest==7.2.0"]
 ```
+
+## Standard library dependencies (DEP005)
+
+Dependencies that are part of the Python standard library should not be defined as dependencies in your project.
+
+### Example
+
+On a project with the following dependencies:
+
+```toml
+[project]
+dependencies = [
+    "asyncio",
+]
+```
+
+and the following `main.py` in the project:
+
+```python
+import asyncio
+
+def async_example():
+    return asyncio.run(some_coroutine())
+```
+
+_deptry_ will report `asyncio` as a standard library dependency because it is part of the standard library, yet it is defined as a dependency in the project.
+
+To fix the issue, `asyncio` should be removed from `[project.dependencies]`:
+
+```toml
+[project]
+dependencies = []
+```

python/deptry/core.py

@@ -59,29 +59,28 @@
 
         python_files = self._find_python_files()
         local_modules = self._get_local_modules()
-        stdlib_modules = self._get_stdlib_modules()
+        standard_library_modules = self._get_standard_library_modules()
 
         imported_modules_with_locations = [
             ModuleLocations(
                 ModuleBuilder(
                     module,
                     local_modules,
-                    stdlib_modules,
+                    standard_library_modules,
                     dependencies_extract.dependencies,
                     dependencies_extract.dev_dependencies,
                 ).build(),
                 locations,
             )
             for module, locations in get_imported_modules_from_list_of_files(python_files).items()
         ]
-        imported_modules_with_locations = [
-            module_with_locations
-            for module_with_locations in imported_modules_with_locations
-            if not module_with_locations.module.standard_library
-        ]
 
         violations = find_violations(
-            imported_modules_with_locations, dependencies_extract.dependencies, self.ignore, self.per_rule_ignores
+            imported_modules_with_locations,
+            dependencies_extract.dependencies,
+            self.ignore,
+            self.per_rule_ignores,
+            standard_library_modules,
         )
         TextReporter(violations, use_ansi=not self.no_ansi).report()
 
@@ -126,7 +125,7 @@
         )
 
     @staticmethod
-    def _get_stdlib_modules() -> frozenset[str]:
+    def _get_standard_library_modules() -> frozenset[str]:
         if sys.version_info[:2] >= (3, 10):
             return sys.stdlib_module_names
 

python/deptry/module.py

@@ -64,7 +64,7 @@ def __init__(
         self,
         name: str,
         local_modules: set[str],
-        stdlib_modules: frozenset[str],
+        standard_library_modules: frozenset[str],
         dependencies: list[Dependency] | None = None,
         dev_dependencies: list[Dependency] | None = None,
     ) -> None:
@@ -74,13 +74,13 @@ def __init__(
         Args:
             name: The name of the imported module
             local_modules: The list of local modules
-            stdlib_modules: The list of Python stdlib modules
+            standard_library_modules: The list of Python stdlib modules
             dependencies: A list of the project's dependencies
             dev_dependencies: A list of the project's development dependencies
         """
         self.name = name
         self.local_modules = local_modules
-        self.stdlib_modules = stdlib_modules
+        self.standard_library_modules = standard_library_modules
         self.dependencies = dependencies or []
         self.dev_dependencies = dev_dependencies or []
 
@@ -137,7 +137,7 @@ def _get_corresponding_top_levels_from(self, dependencies: list[Dependency]) ->
         ]
 
     def _in_standard_library(self) -> bool:
-        return self.name in self.stdlib_modules
+        return self.name in self.standard_library_modules
 
     def _is_local_module(self) -> bool:
         """

python/deptry/violations/__init__.py

@@ -9,16 +9,20 @@
 from deptry.violations.dep003_transitive.violation import DEP003TransitiveDependencyViolation
 from deptry.violations.dep004_misplaced_dev.finder import DEP004MisplacedDevDependenciesFinder
 from deptry.violations.dep004_misplaced_dev.violation import DEP004MisplacedDevDependencyViolation
+from deptry.violations.dep005_standard_library.finder import DEP005StandardLibraryDependencyFinder
+from deptry.violations.dep005_standard_library.violation import DEP005StandardLibraryDependencyViolation
 
 __all__ = (
     "DEP001MissingDependencyViolation",
     "DEP002UnusedDependencyViolation",
     "DEP003TransitiveDependencyViolation",
     "DEP004MisplacedDevDependencyViolation",
+    "DEP005StandardLibraryDependencyViolation",
     "DEP001MissingDependenciesFinder",
     "DEP002UnusedDependenciesFinder",
     "DEP003TransitiveDependenciesFinder",
     "DEP004MisplacedDevDependenciesFinder",
+    "DEP005StandardLibraryDependencyFinder",
     "Violation",
     "ViolationsFinder",
 )

python/deptry/violations/base.py

@@ -10,7 +10,6 @@
     from deptry.module import Module, ModuleLocations
 
 
-@dataclass
 class ViolationsFinder(ABC):
     """Base class for all issues finders.
 
@@ -23,13 +22,19 @@ class ViolationsFinder(ABC):
         dependencies: A list of Dependency objects representing the project's dependencies.
         ignored_modules: A tuple of module names to ignore when scanning for issues. Defaults to an
             empty tuple.
-
     """
 
     violation: ClassVar[type[Violation]]
-    imported_modules_with_locations: list[ModuleLocations]
-    dependencies: list[Dependency]
-    ignored_modules: tuple[str, ...] = ()
+
+    def __init__(
+        self,
+        imported_modules_with_locations: list[ModuleLocations],
+        dependencies: list[Dependency],
+        ignored_modules: tuple[str, ...] = (),
+    ):
+        self.imported_modules_with_locations = imported_modules_with_locations
+        self.dependencies = dependencies
+        self.ignored_modules = ignored_modules
 
     @abstractmethod
     def find(self) -> list[Violation]:

python/deptry/violations/dep001_missing/finder.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
 from deptry.violations.base import ViolationsFinder
@@ -12,7 +11,6 @@
     from deptry.violations.base import Violation
 
 
-@dataclass
 class DEP001MissingDependenciesFinder(ViolationsFinder):
     """
     Given a list of imported modules and a list of project dependencies, determine which ones are missing.
@@ -27,6 +25,9 @@ def find(self) -> list[Violation]:
         for module_with_locations in self.imported_modules_with_locations:
             module = module_with_locations.module
 
+            if module.standard_library:
+                continue
+
             logging.debug("Scanning module %s...", module.name)
 
             if self._is_missing(module):

python/deptry/violations/dep002_unused/finder.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
 from deptry.imports.location import Location
@@ -13,7 +12,6 @@
     from deptry.violations import Violation
 
 
-@dataclass
 class DEP002UnusedDependenciesFinder(ViolationsFinder):
     """
     Finds unused dependencies by comparing a list of imported modules to a list of project dependencies.

python/deptry/violations/dep003_transitive/finder.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
 from deptry.violations.base import ViolationsFinder
@@ -12,7 +11,6 @@
     from deptry.violations import Violation
 
 
-@dataclass
 class DEP003TransitiveDependenciesFinder(ViolationsFinder):
     """
     Given a list of imported modules and a list of project dependencies, determine which ones are transitive.
@@ -34,6 +32,9 @@ def find(self) -> list[Violation]:
         for module_with_locations in self.imported_modules_with_locations:
             module = module_with_locations.module
 
+            if module.standard_library:
+                continue
+
             logging.debug("Scanning module %s...", module.name)
 
             if self._is_transitive(module):

python/deptry/violations/dep004_misplaced_dev/finder.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
 from deptry.violations.base import ViolationsFinder
@@ -12,7 +11,6 @@
     from deptry.violations import Violation
 
 
-@dataclass
 class DEP004MisplacedDevDependenciesFinder(ViolationsFinder):
     """
     Given a list of imported modules and a list of project dependencies, determine which development dependencies
@@ -35,6 +33,9 @@
         for module_with_locations in self.imported_modules_with_locations:
             module = module_with_locations.module
 
+            if module.standard_library:
+                continue
+
             logging.debug("Scanning module %s...", module.name)
             corresponding_package_name = self._get_package_name(module)
 

python/deptry/violations/dep005_standard_library/finder.py

@@ -0,0 +1,53 @@
+from __future__ import annotations
+
+import logging
+from typing import TYPE_CHECKING
+
+from deptry.imports.location import Location
+from deptry.violations.base import ViolationsFinder
+from deptry.violations.dep005_standard_library.violation import DEP005StandardLibraryDependencyViolation
+
+if TYPE_CHECKING:
+    from deptry.dependency import Dependency
+    from deptry.module import ModuleLocations
+    from deptry.violations import Violation
+
+
+class DEP005StandardLibraryDependencyFinder(ViolationsFinder):
+    """
+    Finds dependencies that are part of the standard library but are defined as dependencies.
+    """
+
+    violation = DEP005StandardLibraryDependencyViolation
+
+    def __init__(
+        self,
+        imported_modules_with_locations: list[ModuleLocations],
+        dependencies: list[Dependency],
+        standard_library_modules: frozenset[str],
+        ignored_modules: tuple[str, ...] = (),
+    ):
+        super().__init__(imported_modules_with_locations, dependencies, ignored_modules)
+        self.standard_library_modules = standard_library_modules
+
+    def find(self) -> list[Violation]:
+        logging.debug("\nScanning for dependencies that are part of the standard library...")
+        stdlib_violations: list[Violation] = []
+
+        for dependency in self.dependencies:
+            logging.debug("Scanning module %s...", dependency.name)
+
+            if dependency.name in self.standard_library_modules:
+                if dependency.name in self.ignored_modules:
+                    logging.debug(
+                        "Dependency '%s' found to be a dependency that is part of the standard library, but ignoring.",
+                        dependency.name,
+                    )
+                    continue
+
+                logging.debug(
+                    "Dependency '%s' marked as a dependency that is part of the standard library.", dependency.name
+                )
+                stdlib_violations.append(self.violation(dependency, Location(dependency.definition_file)))
+
+        return stdlib_violations

python/deptry/violations/dep005_standard_library/violation.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import TYPE_CHECKING, ClassVar
+
+from deptry.violations.base import Violation
+
+if TYPE_CHECKING:
+    from deptry.dependency import Dependency
+
+
+@dataclass
+class DEP005StandardLibraryDependencyViolation(Violation):
+    error_code: ClassVar[str] = "DEP005"
+    error_template: ClassVar[str] = (
+        "'{name}' is defined as a dependency but it is included in the Python standard library."
+    )
+    issue: Dependency
+
+    def get_error_message(self) -> str:
+        return self.error_template.format(name=self.issue.name)

python/deptry/violations/finder.py

@@ -8,6 +8,7 @@
     DEP002UnusedDependenciesFinder,
     DEP003TransitiveDependenciesFinder,
     DEP004MisplacedDevDependenciesFinder,
+    DEP005StandardLibraryDependencyFinder,
 )
 
 if TYPE_CHECKING:
@@ -31,19 +32,32 @@
     dependencies: list[Dependency],
     ignore: tuple[str, ...],
     per_rule_ignores: Mapping[str, tuple[str, ...]],
+    standard_library_modules: frozenset[str],
 ) -> list[Violation]:
     violations = []
 
     for violation_finder in _VIOLATIONS_FINDERS:
         if violation_finder.violation.error_code not in ignore:
             violations.extend(
                 violation_finder(
-                    imported_modules_with_locations,
-                    dependencies,
-                    per_rule_ignores.get(violation_finder.violation.error_code, ()),
+                    imported_modules_with_locations=imported_modules_with_locations,
+                    dependencies=dependencies,
+                    ignored_modules=per_rule_ignores.get(violation_finder.violation.error_code, ()),
                 ).find()
             )
 
+    # Since DEP005StandardLibraryDependencyFinder has a different constructor than the other 4 classes,
+    # we handle it separately.
+    if DEP005StandardLibraryDependencyFinder.violation.error_code not in ignore:
+        violations.extend(
+            DEP005StandardLibraryDependencyFinder(
+                imported_modules_with_locations=imported_modules_with_locations,
+                dependencies=dependencies,
+                ignored_modules=per_rule_ignores.get(violation_finder.violation.error_code, ()),
+                standard_library_modules=standard_library_modules,
+            ).find()
+        )
+
     return _get_sorted_violations(violations)