fix: tighten types and move textcase to module scope in custom delimiter loading

src/codeweaver/engine/chunker/delimiter.py

@@ -11,13 +11,24 @@
 
 from __future__ import annotations
 
+import logging
 import re
 
 from datetime import UTC, datetime
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, NamedTuple, cast
 
-from codeweaver.core import CodeChunk, Metadata, Span, get_blake_hash, uuid7
+import textcase
+
+from codeweaver.core import (
+    CodeChunk,
+    ConfigLanguage,
+    Metadata,
+    SemanticSearchLanguage,
+    Span,
+    get_blake_hash,
+    uuid7,
+)
 from codeweaver.engine.chunker.base import AdaptiveChunkBehavior, BaseChunker, ChunkGovernor
 from codeweaver.engine.chunker.delimiter_model import Boundary, Delimiter, DelimiterMatch
 from codeweaver.engine.chunker.exceptions import (
@@ -32,6 +43,8 @@
     from codeweaver.core import DiscoveredFile
 
 
+logger = logging.getLogger(__name__)
+
 PERFORMANCE_THRESHOLD_MS = 1000.0  # 1 second
 
 # Token estimation: ~4 chars per token for code (conservative)
@@ -1256,7 +1269,7 @@ def _load_custom_delimiters(
         self,
         normalized_language: str,
         language: str,
-    ) -> list[object]:
+    ) -> list[Delimiter]:
         """Load custom delimiter patterns from settings that match the given language.
 
         Custom delimiters are returned first so they override built-in family
@@ -1269,28 +1282,19 @@ def _load_custom_delimiters(
         Returns:
             List of ``Delimiter`` objects converted from matching custom patterns.
         """
-        import logging
-
-        import textcase
-
-        from codeweaver.core import ConfigLanguage, SemanticSearchLanguage
-        from codeweaver.engine.chunker.delimiter_model import Delimiter
-
         if (
             self._governor.settings is None
             or not hasattr(self._governor.settings, "custom_delimiters")
             or not self._governor.settings.custom_delimiters
         ):
             return []
 
-        logger = logging.getLogger(__name__)
-
         def _normalize(lang: object) -> str:
             if isinstance(lang, SemanticSearchLanguage | ConfigLanguage):
                 return textcase.snake(lang.variable)
             return textcase.snake(str(lang))
 
-        delimiters: list[object] = []
+        delimiters: list[Delimiter] = []
         for custom_delim in self._governor.settings.custom_delimiters:
             lang_match = (
                 custom_delim.language is not None
@@ -1327,9 +1331,7 @@ def _load_delimiters_for_language(self, language: str) -> list[Delimiter]:
             List of Delimiter objects for the language, with custom delimiters
             prepended so they take priority over built-in family patterns.
         """
-        import textcase
-
-        from codeweaver.engine.chunker.delimiter_model import Delimiter, DelimiterKind
+        from codeweaver.engine.chunker.delimiter_model import DelimiterKind
         from codeweaver.engine.chunker.delimiters.families import (
             LanguageFamily,
             get_family_patterns,
@@ -1339,7 +1341,7 @@ def _load_delimiters_for_language(self, language: str) -> list[Delimiter]:
 
         # Custom entries are prepended so they override the built-in family
         # patterns for known languages and are the sole source for new languages.
-        delimiters: list[Delimiter] = self._load_custom_delimiters(  # type: ignore[assignment]
+        delimiters: list[Delimiter] = self._load_custom_delimiters(
             normalized_language, language
         )
 

src/codeweaver/engine/chunker/selector.py

@@ -21,6 +21,8 @@
 
 from typing import TYPE_CHECKING, Any
 
+import textcase
+
 from codeweaver.core import ConfigLanguage, SemanticSearchLanguage
 from codeweaver.engine.chunker.base import BaseChunker
 from codeweaver.engine.chunker.delimiter import DelimiterChunker
@@ -216,29 +218,25 @@ def _detect_language_from_custom_ext(
         if self.governor.settings is None:
             return None
 
-        import textcase
-
         custom_delimiters = getattr(self.governor.settings, "custom_delimiters", None)
         if not custom_delimiters:
             return None
 
         for custom_delim in custom_delimiters:
-            if lang := self._match_custom_ext_pair(custom_delim, file_ext, textcase):
+            if lang := self._match_custom_ext_pair(custom_delim, file_ext):
                 return lang
         return None
 
     @staticmethod
     def _match_custom_ext_pair(
         custom_delim: object,
         file_ext: str,
-        textcase: object,
     ) -> SemanticSearchLanguage | ConfigLanguage | str | None:
         """Return the language for a matching extension pair in *custom_delim*.
 
         Args:
             custom_delim: A ``CustomDelimiter`` instance from settings.
             file_ext: File extension including the leading dot.
-            textcase: The textcase module (passed in to avoid repeated imports).
 
         Returns:
             Matching language, or ``None``.
@@ -256,12 +254,14 @@ def _match_custom_ext_pair(
                 continue
             delim_lang = getattr(custom_delim, "language", None)
             if delim_lang is not None:
-                return textcase.snake(str(delim_lang))  # type: ignore[attr-defined]
+                if isinstance(delim_lang, SemanticSearchLanguage | ConfigLanguage):
+                    return delim_lang
+                return textcase.snake(str(delim_lang))
             pair_lang = getattr(pair, "language", None)
             if pair_lang is not None:
                 if isinstance(pair_lang, SemanticSearchLanguage | ConfigLanguage):
                     return pair_lang
-                return textcase.snake(str(pair_lang))  # type: ignore[attr-defined]
+                return textcase.snake(str(pair_lang))
         return None
 
     def _detect_language(