Only use numeric collation for sorting since it breaks searching

src/calibre/utils/icu.c

@@ -59,7 +59,6 @@ icu_Collator_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
         PyErr_SetString(PyExc_Exception, "Failed to create collator.");
         return NULL;
     }
-    ucol_setAttribute(collator, UCOL_NUMERIC_COLLATION, UCOL_ON, &status);
 
     self = (icu_Collator *)type->tp_alloc(type, 0);
     if (self != NULL) {

src/calibre/utils/icu.py

@@ -12,7 +12,7 @@ from functools import partial
 from calibre.constants import plugins
 from calibre.utils.config_base import tweaks
 
-_icu = _collator = _primary_collator = _secondary_collator = None
+_icu = _collator = _primary_collator = _sort_collator = None
 _locale = None
 
 _none = u''
@@ -41,28 +41,34 @@ def load_icu():
     return _icu
 
 def load_collator():
+    'The default collator for most locales takes both case and accented letters into account'
     global _collator
     if _collator is None:
         icu = load_icu()
         if icu is not None:
             _collator = icu.Collator(get_locale())
-            if not tweaks['numeric_collation']:
-                _collator.numeric = False
     return _collator
 
 def primary_collator():
+    'Ignores case differences and accented characters'
     global _primary_collator
     if _primary_collator is None:
         _primary_collator = _collator.clone()
         _primary_collator.strength = _icu.UCOL_PRIMARY
     return _primary_collator
 
-def secondary_collator():
-    global _secondary_collator
-    if _secondary_collator is None:
-        _secondary_collator = _collator.clone()
-        _secondary_collator.strength = _icu.UCOL_SECONDARY
-    return _secondary_collator
+def sort_collator():
+    'Ignores case differences and recognizes numbers in strings'
+    global _sort_collator
+    if _sort_collator is None:
+        _sort_collator = _collator.clone()
+        _sort_collator.strength = _icu.UCOL_SECONDARY
+        if tweaks['numeric_collation']:
+            try:
+                _sort_collator.numeric = True
+            except AttributeError:
+                pass
+    return _sort_collator
 
 def py_sort_key(obj):
     if not obj:
@@ -74,15 +80,15 @@ def icu_sort_key(collator, obj):
         return _none2
     try:
         try:
-            return _secondary_collator.sort_key(obj)
+            return _sort_collator.sort_key(obj)
         except AttributeError:
-            return secondary_collator().sort_key(obj)
+            return sort_collator().sort_key(obj)
     except TypeError:
         if isinstance(obj, unicode):
             obj = obj.replace(u'\0', u'')
         else:
             obj = obj.replace(b'\0', b'')
-        return _secondary_collator.sort_key(obj)
+        return _sort_collator.sort_key(obj)
 
 def icu_change_case(upper, locale, obj):
     func = _icu.upper if upper else _icu.lower
@@ -235,9 +241,9 @@ def collation_order(a):
     if _icu_not_ok:
         return (ord(a[0]), 1) if a else (0, 0)
     try:
-        return icu_collation_order(_secondary_collator, a)
+        return icu_collation_order(_sort_collator, a)
     except AttributeError:
-        return icu_collation_order(secondary_collator(), a)
+        return icu_collation_order(sort_collator(), a)
 
 ################################################################################