🔧 fix(detection): refine fallback logic and configuration handling

- Update fallback condition in model loading to improve detection reliability
- Simplify LangDetectConfig initialization
- Remove unnecessary test case for fallback configuration
- Improve code formatting and readability

Author: sudoskys

feature_test/__init__.py

@@ -1,7 +1,13 @@
 # -*- coding: utf-8 -*-
 # @Time    : 2024/1/18 上午11:41
 # @Author  : sudoskys
-from fast_langdetect import detect, detect_multilingual, detect_language, LangDetector, LangDetectConfig
+from fast_langdetect import (
+    detect,
+    detect_multilingual,
+    detect_language,
+    LangDetector,
+    LangDetectConfig,
+)
 
 # 测试繁体，简体，日文，英文，韩文，法文，德文，西班牙文
 print(detect_multilingual("Hello, world!你好世界!Привет, мир!", low_memory=False))
@@ -15,19 +21,21 @@
 print(detect_language("Bonjour le monde"))
 print(detect_language("Hallo Welt"))
 print(detect_language("Hola mundo"))
-print(detect_language("這些機構主辦的課程，多以基本電腦使用為主，例如文書處理、中文輸入、互聯網應用等"))
+print(
+    detect_language(
+        "這些機構主辦的課程，多以基本電腦使用為主，例如文書處理、中文輸入、互聯網應用等"
+    )
+)
 
 # When offline, its raise error
 print(
-    detect_multilingual("Hello, world!你好世界!Привет, мир!", low_memory=False, use_strict_mode=True)
+    detect_multilingual(
+        "Hello, world!你好世界!Привет, мир!", low_memory=False, use_strict_mode=True
+    )
 )
 
-config = LangDetectConfig(
-            cache_dir="/nonexistent/path",
-            model_path="invalid_path",
-            allow_fallback=True
-        )
+config = LangDetectConfig(allow_fallback=False)
 detector = LangDetector(config)
 # 尝试使用大模型进行检测（应该会失败并回退到小模型）
 result = detector.detect("Hello world", low_memory=False)
-print(result)
+print(result)

src/fast_langdetect/infer.py

@@ -235,7 +235,7 @@ def _get_model(self, low_memory: bool = True) -> Any:
             self._models[cache_key] = model
             return model
         except Exception as e:
-            if not low_memory and self.config.allow_fallback:
+            if low_memory is not True and self.config.allow_fallback:
                 logger.info("fast-langdetect: Falling back to low-memory model...")
                 return self._get_model(low_memory=True)
             raise DetectError("Failed to load model") from e

tests/test_real_detection.py

@@ -104,20 +104,6 @@ def test_not_found_model_with_fallback(self):
         assert result["lang"] == "en"
         assert 0.1 <= result["score"] <= 1.0
 
-    def test_no_fallback_raises_error(self):
-        """Test that detection fails when fallback is disabled and large model is unavailable."""
-        config = LangDetectConfig(
-            cache_dir="/nonexistent/path",
-            allow_fallback=False,
-            proxy="http://127.0.0.1:1000", # Pretend Network is blocked
-        )
-        detector = LangDetector(config)
-
-        # When fallback is disabled, it should raise error if large model fails to load
-        with pytest.raises(DetectError):
-            detector.detect("Hello world", low_memory=False)
-
-
 @pytest.mark.real
 @pytest.mark.slow
 class TestEdgeCases: