suffix-based colorization for numeric value diffs

beets/ui/__init__.py

@@ -414,6 +414,29 @@ def colordiff(a, b, highlight='red'):
     else:
         return unicode(a), unicode(b)
 
+def color_diff_suffix(a, b, highlight='red'):
+    """Colorize the differing suffix between two strings."""
+    a, b = unicode(a), unicode(b)
+    if not config['color']:
+        return a, b
+
+    # Fast path.
+    if a == b:
+        return a, b
+
+    # Find the longest common prefix.
+    first_diff = None
+    for i in range(min(len(a), len(b))):
+        if a[i] != b[i]:
+            first_diff = i
+            break
+    else:
+        first_diff = min(len(a), len(b))
+
+    # Colorize from the first difference on.
+    return a[:first_diff] + colorize(highlight, a[first_diff:]), \
+           b[:first_diff] + colorize(highlight, b[first_diff:])
+
 def get_path_formats():
     """Get the configuration's path formats as a list of query/template
     pairs.

beets/ui/commands.py

@@ -201,9 +201,11 @@ def show_change(cur_artist, cur_album, match):
         # Track number change.
         if item.track not in (track_info.index, track_info.medium_index):
             cur_track, new_track = unicode(item.track), format_index(track_info)
-            lhs_track, rhs_track = ui.colordiff(cur_track, new_track)
-            lhs += u' (#%s)' % lhs_track
-            rhs += u' (#%s)' % rhs_track
+            lhs_track, rhs_track = ui.color_diff_suffix(cur_track, new_track)
+            templ = ui.colorize('red', u' (#') + u'{0}' + \
+                    ui.colorize('red', u')')
+            lhs += templ.format(lhs_track)
+            rhs += templ.format(rhs_track)
             lhs_width += len(cur_track) + 4
 
         # Length change.
@@ -212,9 +214,12 @@ def show_change(cur_artist, cur_album, match):
                 config['ui']['length_diff_thresh'].as_number():
             cur_length = ui.human_seconds_short(item.length)
             new_length = ui.human_seconds_short(track_info.length)
-            lhs_length, rhs_length = ui.colordiff(cur_length, new_length)
-            lhs += u' (%s)' % lhs_length
-            rhs += u' (%s)' % rhs_length
+            lhs_length, rhs_length = ui.color_diff_suffix(cur_length,
+                                                          new_length)
+            templ = ui.colorize('red', u' (') + u'{0}' + \
+                    ui.colorize('red', u')')
+            lhs += templ.format(lhs_length)
+            rhs += templ.format(rhs_length)
             lhs_width += len(cur_length) + 3
 
         if lhs != rhs:

docs/changelog.rst

@@ -30,10 +30,14 @@ Other new stuff:
     bad: "low" or "none" recommendations or when choosing a candidate
     other than the first.
 
-* Album listings in the importer UI now show the release medium (CD, LP,
+* Album listings in the importer UI now show the release medium (CD, Vinyl,
   etc.). Thanks to Peter Schnebel.
 * :doc:`/plugins/mpdupdate`: Sends an update message whenever *anything* in the
   database changes---not just when importing. Thanks to Dang Mai Hai.
+* When the importer UI shows a difference in track numbers or durations, they
+  are now colorized based on the *suffixes* that differ. For example, when
+  showing the difference between 2:01 and 2:09, only the last digit will be
+  highlighted.
 * The importer UI no longer shows a change when the track length difference is
   less than 10 seconds. (This threshold was previously 2 seconds.)
 * Fix an error when migrating the ``.beetsstate`` file on Windows.