usethis-python · nathanjmcdougall · Mar 21, 2026 · Mar 20, 2026 · Mar 20, 2026 · Mar 20, 2026
diff --git a/pyproject.toml b/pyproject.toml
@@ -144,7 +144,6 @@ lint.select = [
 lint.ignore = [ "PLR2004", "S101", "SIM108" ]
 lint.per-file-ignores."!tests/**/*.py" = [ "ARG002", "PT" ]
 lint.per-file-ignores."src/usethis/_ui/interface/**/*.py" = [ "PLR0913" ]
-
 lint.per-file-ignores."tests/**" = [ "D", "INP", "S603", "TC" ]
 lint.flake8-bugbear.extend-immutable-calls = [ "typer.Argument", "typer.Option" ]
 lint.flake8-builtins.strict-checking = true
@@ -155,6 +154,7 @@ lint.flake8-type-checking.quote-annotations = true
 lint.flake8-type-checking.runtime-evaluated-base-classes = [ "pydantic.BaseModel" ]
 lint.flake8-type-checking.strict = true
 lint.pydocstyle.convention = "google"
+lint.future-annotations = true
 
 [tool.codespell]
 skip = [ "site" ]

diff --git a/src/usethis/_backend/uv/deps.py b/src/usethis/_backend/uv/deps.py
@@ -2,6 +2,8 @@
 
 from typing import TYPE_CHECKING
 
+from pydantic import TypeAdapter, ValidationError
+
 from usethis._backend.uv.call import call_uv_subprocess
 from usethis._backend.uv.errors import (
     UVDepGroupError,
@@ -37,12 +39,14 @@ def get_default_groups_via_uv() -> list[str]:
     """Get the default dependency groups from the uv configuration."""
     try:
         if UVTOMLManager().path.exists():
-            default_groups = UVTOMLManager()[["default-groups"]]
+            default_groups = TypeAdapter(list[str]).validate_python(
+                UVTOMLManager()[["default-groups"]]
+            )
         else:
-            default_groups = PyprojectTOMLManager()[["tool", "uv", "default-groups"]]
-        if not isinstance(default_groups, list):
-            default_groups = []
-    except KeyError:
+            default_groups = TypeAdapter(list[str]).validate_python(
+                PyprojectTOMLManager()[["tool", "uv", "default-groups"]]
+            )
+    except (KeyError, ValidationError):
         default_groups = []
 
     return default_groups
diff --git a/src/usethis/_core/status.py b/src/usethis/_core/status.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from pydantic import TypeAdapter, ValidationError
+
 from usethis._console import tick_print
 from usethis._file.pyproject_toml.io_ import PyprojectTOMLManager
 from usethis._init import ensure_pyproject_toml
@@ -19,8 +21,10 @@ def use_development_status(
 
     mgr = PyprojectTOMLManager()
     try:
-        existing_classifiers = mgr[["project", "classifiers"]]
-    except KeyError:
+        existing_classifiers = TypeAdapter(list[str]).validate_python(
+            mgr[["project", "classifiers"]]
+        )
+    except (KeyError, ValidationError):
         existing_classifiers = []
     existing_status_classifiers = {
         classifier

diff --git a/src/usethis/_file/ini/io_.py b/src/usethis/_file/ini/io_.py
@@ -113,7 +113,7 @@ def __contains__(self, keys: Sequence[Key]) -> bool:
                     return True
         return False
 
-    def __getitem__(self, item: Sequence[Key]) -> Any:
+    def __getitem__(self, item: Sequence[Key]) -> object:
         keys = item
 
         root = self.get()

diff --git a/src/usethis/_file/toml/io_.py b/src/usethis/_file/toml/io_.py
@@ -114,7 +114,7 @@ def __contains__(self, keys: Sequence[Key]) -> bool:
 
         return True
 
-    def __getitem__(self, item: Sequence[Key]) -> Any:
+    def __getitem__(self, item: Sequence[Key]) -> object:
         keys = item
         keys = _validate_keys(keys)
 

diff --git a/src/usethis/_file/yaml/io_.py b/src/usethis/_file/yaml/io_.py
@@ -125,7 +125,7 @@ def __contains__(self, keys: Sequence[Key]) -> bool:
 
         return True
 
-    def __getitem__(self, item: Sequence[Key]) -> Any:
+    def __getitem__(self, item: Sequence[Key]) -> object:
         keys = item
         keys = _validate_keys(keys)
 

diff --git a/src/usethis/_integrations/sonarqube/config.py b/src/usethis/_integrations/sonarqube/config.py
@@ -2,7 +2,7 @@
 
 import re
 
-from pydantic import TypeAdapter
+from pydantic import TypeAdapter, ValidationError
 
 from usethis._config import usethis_config
 from usethis._file.pyproject_toml.io_ import PyprojectTOMLManager
@@ -71,38 +71,40 @@ def get_sonar_project_properties() -> str:
 
 def _get_sonarqube_project_key() -> str:
     try:
-        project_key = PyprojectTOMLManager()[
-            ["tool", "usethis", "sonarqube", "project-key"]
-        ]
+        project_key = TypeAdapter(str).validate_python(
+            PyprojectTOMLManager()[["tool", "usethis", "sonarqube", "project-key"]]
+        )
     except KeyError:
         msg = "Could not find SonarQube project key at 'tool.usethis.sonarqube.project-key' in 'pyproject.toml'."
         raise MissingProjectKeyError(msg) from None
     except FileNotFoundError:
         msg = "Could not find 'pyproject.toml' for SonarQube project key at 'tool.usethis.sonarqube.project-key'."
         raise MissingProjectKeyError(msg) from None
+    except ValidationError:
+        msg = "SonarQube project key at 'tool.usethis.sonarqube.project-key' in 'pyproject.toml' must be a string."
+        raise InvalidSonarQubeProjectKeyError(msg) from None
     _validate_project_key(project_key)
     return project_key
 
 
 def _is_sonarqube_verbose() -> bool:
     try:
-        verbose = PyprojectTOMLManager()[["tool", "usethis", "sonarqube", "verbose"]]
-    except (FileNotFoundError, KeyError):
+        verbose = TypeAdapter(bool).validate_python(
+            PyprojectTOMLManager()[["tool", "usethis", "sonarqube", "verbose"]]
+        )
+    except (FileNotFoundError, KeyError, ValidationError):
         verbose = False
-    verbose = TypeAdapter(bool).validate_python(verbose)
 
     return verbose
 
 
 def _get_sonarqube_exclusions() -> list[str]:
     try:
-        exclusions = PyprojectTOMLManager()[
-            ["tool", "usethis", "sonarqube", "exclusions"]
-        ]
-    except (FileNotFoundError, KeyError):
+        exclusions = TypeAdapter(list).validate_python(
+            PyprojectTOMLManager()[["tool", "usethis", "sonarqube", "exclusions"]]
+        )
+    except (FileNotFoundError, KeyError, ValidationError):
         exclusions = []
-    # TypeAdapter(list).validate_python() ensures we have a list and returns a new list
-    exclusions = TypeAdapter(list).validate_python(exclusions)
     for exclusion in exclusions:
         TypeAdapter(str).validate_python(exclusion)
 

diff --git a/src/usethis/_io.py b/src/usethis/_io.py
@@ -189,7 +189,7 @@ def __contains__(self, keys: Sequence[Key]) -> bool:
         raise NotImplementedError
 
     @abstractmethod
-    def __getitem__(self, keys: Sequence[Key]) -> Any:
+    def __getitem__(self, keys: Sequence[Key]) -> object:
         raise NotImplementedError
 
     def __setitem__(self, keys: Sequence[Key], value: Any) -> None:

diff --git a/src/usethis/_tool/impl/base/deptry.py b/src/usethis/_tool/impl/base/deptry.py
@@ -2,14 +2,16 @@
 
 from typing import TYPE_CHECKING, final
 
+from pydantic import TypeAdapter, ValidationError
+
 from usethis._console import info_print
 from usethis._file.pyproject_toml.io_ import PyprojectTOMLManager
 from usethis._tool.base import Tool
 from usethis._tool.impl.spec.deptry import DeptryToolSpec
+from usethis._tool.rule import Rule
 
 if TYPE_CHECKING:
     from usethis._io import KeyValueFileManager
-    from usethis._tool.rule import Rule
 
 
 class DeptryTool(DeptryToolSpec, Tool):
@@ -39,8 +41,8 @@ def ignored_rules(self) -> list[Rule]:
         (file_manager,) = self.get_active_config_file_managers()
         keys = self._get_ignore_keys(file_manager)
         try:
-            rules: list[Rule] = file_manager[keys]
-        except (KeyError, FileNotFoundError):
+            rules = TypeAdapter(list[Rule]).validate_python(file_manager[keys])
+        except (KeyError, FileNotFoundError, ValidationError):
             rules = []
 
         return rules

diff --git a/src/usethis/_tool/impl/base/ruff.py b/src/usethis/_tool/impl/base/ruff.py
@@ -3,6 +3,7 @@
 from pathlib import Path
 from typing import TYPE_CHECKING, Literal, final
 
+from pydantic import TypeAdapter, ValidationError
 from typing_extensions import assert_never
 
 from usethis._backend.dispatch import get_backend
@@ -30,7 +31,7 @@
 
 if TYPE_CHECKING:
     from usethis._io import KeyValueFileManager
-    from usethis._tool.rule import Rule, RuleConfig
+    from usethis._tool.rule import RuleConfig
 
 _RUFF_VERSION = "v0.15.4"  # Manually bump this version when necessary
 
@@ -204,8 +205,8 @@ def selected_rules(self) -> list[Rule]:
 
         keys = self._get_select_keys(file_manager)
         try:
-            rules: list[Rule] = file_manager[keys]
-        except (KeyError, FileNotFoundError):
+            rules = TypeAdapter(list[Rule]).validate_python(file_manager[keys])
+        except (KeyError, FileNotFoundError, ValidationError):
             rules = []
 
         return rules
@@ -216,8 +217,8 @@ def ignored_rules(self) -> list[Rule]:
         (file_manager,) = self.get_active_config_file_managers()
         keys = self._get_ignore_keys(file_manager)
         try:
-            rules: list[Rule] = file_manager[keys]
-        except (KeyError, FileNotFoundError):
+            rules = TypeAdapter(list[Rule]).validate_python(file_manager[keys])
+        except (KeyError, FileNotFoundError, ValidationError):
             rules = []
 
         return rules
@@ -247,8 +248,8 @@ def get_ignored_rules_in_glob(self, glob: str) -> list[Rule]:
         (file_manager,) = self.get_active_config_file_managers()
         keys = self._get_per_file_ignore_keys(file_manager, glob=glob)
         try:
-            rules: list[Rule] = file_manager[keys]
-        except (KeyError, FileNotFoundError):
+            rules = TypeAdapter(list[Rule]).validate_python(file_manager[keys])
+        except (KeyError, FileNotFoundError, ValidationError):
             rules = []
 
         return rules
@@ -309,8 +310,8 @@ def get_docstyle(self) -> Literal["numpy", "google", "pep257"] | None:
         (file_manager,) = self.get_active_config_file_managers()
         keys = self._get_docstyle_keys(file_manager)
         try:
-            docstyle = file_manager[keys]
-        except (KeyError, FileNotFoundError):
+            docstyle = TypeAdapter(str).validate_python(file_manager[keys])
+        except (KeyError, FileNotFoundError, ValidationError):
             docstyle = None
 
         if docstyle not in ("numpy", "google", "pep257"):

diff --git a/tests/usethis/_core/test_core_ci.py b/tests/usethis/_core/test_core_ci.py
@@ -484,7 +484,7 @@ def test_mentioned_in_file(
                 (uv_init_dir / "tests" / "conftest.py").touch()
 
                 with change_cwd(uv_init_dir), files_manager():
-                    PyprojectTOMLManager()[["project"]]["requires-python"] = (
+                    PyprojectTOMLManager()[["project", "requires-python"]] = (
                         ">=3.12,<3.14"
                     )
 
@@ -596,7 +596,7 @@ def test_matrix_enabled_by_default(self, uv_init_dir: Path):
             (uv_init_dir / "tests" / "conftest.py").touch()
 
             with change_cwd(uv_init_dir), files_manager():
-                PyprojectTOMLManager()[["project"]]["requires-python"] = ">=3.12,<3.14"
+                PyprojectTOMLManager()[["project", "requires-python"]] = ">=3.12,<3.14"
 
                 # Act
                 use_ci_bitbucket()
@@ -623,7 +623,7 @@ def test_matrix_disabled_creates_single_step(
                 change_cwd(uv_init_dir),
                 files_manager(),
             ):
-                PyprojectTOMLManager()[["project"]]["requires-python"] = ">=3.12,<3.14"
+                PyprojectTOMLManager()[["project", "requires-python"]] = ">=3.12,<3.14"
 
                 # Act
                 use_ci_bitbucket(matrix_python=False)

diff --git a/tests/usethis/_core/test_core_tool.py b/tests/usethis/_core/test_core_tool.py
@@ -5,6 +5,7 @@
 from unittest.mock import MagicMock
 
 import pytest
+from pydantic import TypeAdapter
 
 import usethis._backend.dispatch
 import usethis._python.version
@@ -1558,9 +1559,11 @@ def test_no_duplicate_inp_rules(self, tmp_path: Path):
                     len(
                         [
                             rule
-                            for rule in RuffTOMLManager()[
-                                ["lint", "per-file-ignores", "tests/**"]
-                            ]
+                            for rule in TypeAdapter(list[str]).validate_python(
+                                RuffTOMLManager()[
+                                    ["lint", "per-file-ignores", "tests/**"]
+                                ]
+                            )
                             if rule == "INP"
                         ]
                     )
@@ -2753,9 +2756,9 @@ def test_registers_test_group(self, tmp_path: Path):
                 use_pytest()
 
                 # Assert
-                default_groups = PyprojectTOMLManager()[
-                    ["tool", "uv", "default-groups"]
-                ]
+                default_groups = TypeAdapter(list[str]).validate_python(
+                    PyprojectTOMLManager()[["tool", "uv", "default-groups"]]
+                )
                 assert "test" in default_groups
 
         @pytest.mark.usefixtures("_vary_network_conn")
@@ -2768,7 +2771,9 @@ def test_registers_test_group_uv_toml(self, tmp_path: Path):
                 use_pytest()
 
                 # Assert
-                default_groups = UVTOMLManager()[["default-groups"]]
+                default_groups = TypeAdapter(list[str]).validate_python(
+                    UVTOMLManager()[["default-groups"]]
+                )
                 assert "test" in default_groups
 
         @pytest.mark.usefixtures("_vary_network_conn")