refactor: remove unused rename helpers

AGENTS.md

@@ -38,9 +38,9 @@ it names.
   its end of life ships in a minor, as 1.11.0 did for 3.10. Installers skip a release whose
   `requires-python` excludes the running interpreter, so no deployed service breaks.
 - **A rename keeps the old name working, with a `DeprecationWarning`, for at least one minor, and
-  the next major deletes it.** The warning names that major. A module-level name goes through
-  `deprecated_module_getattr` plus a `typing.TYPE_CHECKING` alias so type checkers still see it; a
-  config field goes through `BaseConfig._renamed_fields`.
+  the next major deletes it.** The warning names that major. See
+  [#350](https://github.com/modern-python/lite-bootstrap/issues/350) and
+  [#351](https://github.com/modern-python/lite-bootstrap/issues/351) for previous renames.
 - **Every breaking change gets a line in a "Breaking changes" section of the release notes**, as
   [1.12.0](https://github.com/modern-python/lite-bootstrap/releases/tag/1.12.0) has.
 

lite_bootstrap/helpers/warn.py

@@ -6,7 +6,6 @@
 
 _DATACLASS_GENERATED_INIT: typing.Final = "<string>"
 _INTERNAL_MODULES: typing.Final = frozenset({__name__.split(".")[0], "dataclasses"})
-NEXT_MAJOR_VERSION: typing.Final = "3.0"
 
 
 def _is_internal_frame(frame: types.FrameType) -> bool:
@@ -35,27 +34,3 @@ def warn_at_caller(message: str, category: type[Warning] = UserWarning) -> None:
         stacklevel += 1
         frame = frame.f_back
     warnings.warn(message, category=category, stacklevel=stacklevel)
-
-
-def deprecated_module_getattr(
-    module_name: str,
-    aliases: typing.Mapping[str, tuple[object, str | None]],
-) -> typing.Callable[[str], object]:
-    """Build a module `__getattr__` that resolves each old name to its target with a `DeprecationWarning`.
-
-    `aliases` maps an old name to its target and the name that replaces it, or None if nothing does.
-    """
-
-    def __getattr__(name: str) -> object:  # noqa: N807
-        if name not in aliases:
-            msg = f"module {module_name!r} has no attribute {name!r}"
-            raise AttributeError(msg)
-        target, replacement = aliases[name]
-        advice = f"use {replacement} instead" if replacement else "nothing replaces it"
-        warn_at_caller(
-            f"{name} is deprecated and will be removed in lite-bootstrap {NEXT_MAJOR_VERSION}; {advice}.",
-            category=DeprecationWarning,
-        )
-        return target
-
-    return __getattr__

lite_bootstrap/instruments/base.py

@@ -1,10 +1,5 @@
 import dataclasses
 import typing
-from collections.abc import Mapping
-
-from lite_bootstrap.exceptions import ConfigurationError
-from lite_bootstrap.helpers.warn import NEXT_MAJOR_VERSION, warn_at_caller
-from lite_bootstrap.types import UNSET, UnsetType
 
 
 _DEFAULT_SERVICE_NAME: typing.Final = "micro-service"
@@ -18,8 +13,6 @@ class BaseConfig:
     service_version: str | None = None
     service_environment: str | None = None
     service_debug: bool = False
-    # Deprecated field name -> the field that replaced it. The deprecated field defaults to UNSET.
-    _renamed_fields: typing.ClassVar[Mapping[str, str]] = {}
 
     @property
     def service_name_or_default(self) -> str:
@@ -30,34 +23,7 @@ def service_version_or_default(self) -> str:
         return self.service_version or _DEFAULT_SERVICE_VERSION
 
     def __post_init__(self) -> None:
-        """Terminate the MRO __post_init__ cascade safely, after forwarding deprecated field names.
-
-        Subclasses call super().__post_init__() to propagate through multiple-inheritance
-        chains (e.g. FastAPIConfig → CorsConfig → OpenTelemetryConfig → BaseConfig).
-        Without this, the chain would raise AttributeError on object.
-
-        Running first in the cascade, the forwarding copies each deprecated field the caller set into
-        its replacement before any subclass reads it, then resets the deprecated field to UNSET so
-        `dataclasses.replace()` does not see both set.
-        """
-        for old_name, new_name in self._renamed_fields.items():
-            old_value = getattr(self, old_name)
-            if isinstance(old_value, UnsetType):
-                continue
-            new_field = next(field for field in dataclasses.fields(self) if field.name == new_name)
-            new_default = (
-                new_field.default if new_field.default_factory is dataclasses.MISSING else new_field.default_factory()
-            )
-            if getattr(self, new_name) != new_default:
-                msg = f"{old_name} and {new_name} are both set; {old_name} is deprecated, set only {new_name}."
-                raise ConfigurationError(msg)
-            warn_at_caller(
-                f"{old_name} is deprecated and will be removed in lite-bootstrap {NEXT_MAJOR_VERSION}; "
-                f"use {new_name} instead.",
-                category=DeprecationWarning,
-            )
-            object.__setattr__(self, new_name, old_value)
-            object.__setattr__(self, old_name, UNSET)
+        """Terminate the multiple-inheritance __post_init__ cascade for subclasses calling super()."""
 
     @classmethod
     def from_dict(cls, data: dict[str, typing.Any]) -> typing.Self: