Enhancement: add a tweak to provide the sort value for undefined numbers.

resources/default_tweaks.py

@@ -594,3 +594,16 @@ skip_network_check = False
 # Sets the width of the tab stop in the template editor in "average characters".
 # For example, a value of 1 results in a space with the width of one average character.
 template_editor_tab_stop_width = 4
+
+#: Value for undefined numbers when sorting
+# Sets the value to use for undefined numbers when sorting.
+# For example, the value -10 sorts undefined numbers as if they were set to -10.
+# Use 'maximum' for the largest possible number. Use 'minimum' for the smallest
+# possible number. Quotes are optional if entering a number.
+# Examples:
+#   value_for_undefined_numbers_when_sorting = -100
+#   value_for_undefined_numbers_when_sorting = '2'
+#   value_for_undefined_numbers_when_sorting = -0.01
+#   value_for_undefined_numbers_when_sorting = 'minimum'
+#   value_for_undefined_numbers_when_sorting = 'maximum'
+value_for_undefined_numbers_when_sorting = 0

src/calibre/db/fields.py

@@ -25,8 +25,26 @@ def bool_sort_key(bools_are_tristate):
     return (lambda x:{True: 1, False: 2, None: 3}.get(x, 3)) if bools_are_tristate else lambda x:{True: 1, False: 2, None: 2}.get(x, 2)
 
 
+def _get_sort_value_for_undefined_numbers():
+    t = tweaks['value_for_undefined_numbers_when_sorting']
+    try:
+        if t == 'minimum':
+            return float('-inf')
+        if t == 'maximum':
+            return float('inf')
+        return float(t)
+    except:
+        print('***** Bad value in undefined sort number tweak', t)
+        return 0
+
+
+sort_value_for_undefined_numbers = _get_sort_value_for_undefined_numbers()
+
+
 def numeric_sort_key(x):
-    return x or 0
+    # It isn't clear whether this function can ever be called with a non-numeric
+    # argument, but we check just in case
+    return x if type(x) in (int, float) else sort_value_for_undefined_numbers
 
 
 IDENTITY = lambda x: x
@@ -59,7 +77,7 @@ class Field:
         self._default_sort_key = b''
 
         if dt in {'int', 'float', 'rating'}:
-            self._default_sort_key = 0
+            self._default_sort_key = sort_value_for_undefined_numbers
             self._sort_key = numeric_sort_key
         elif dt == 'bool':
             self._default_sort_key = None
@@ -262,7 +280,7 @@ class CompositeField(OneToOneField):
                 val = val[:(-2 if p > 1 else -1)].strip()
             val = atof(val) * p
         except (TypeError, AttributeError, ValueError, KeyError):
-            val = 0.0
+            val = sort_value_for_undefined_numbers
         return val
 
     def date_sort_key(self, val):

src/calibre/gui2/preferences/tweaks.py

@@ -374,6 +374,9 @@ class TweaksView(QListView):
         self.setAlternatingRowColors(True)
         self.setSpacing(5)
         self.setVerticalScrollMode(QAbstractItemView.ScrollMode.ScrollPerPixel)
+        # On windows (at least) the automatic scroll bar appearing hides part
+        # of the last line in the list view. Force it always on.
+        self.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOn)
         self.setMinimumWidth(300)
 
     def currentChanged(self, cur, prev):