Remove prefix diff highlighting

This was well-intentioned but ended up being more confusing than it was worth.
It's always confused me when one digit gets un-highlighted in one of these
displays. The straw that broke the camel's back was when I got a "#1 -> #16"
change where the numeral "1" was un-highlighted. To fix this right would be
way more trouble than it's worth; I'm glad to be rid of this detail.

Conflicts:
	docs/changelog.rst

beets/ui/__init__.py

@@ -441,30 +441,6 @@ def colordiff(a, b, highlight='red'):
         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(subview=None):
     """Get the configuration's path formats as a list of query/template
     pairs.

beets/ui/commands.py

@@ -318,17 +318,9 @@ def show_change(cur_artist, cur_album, match):
                 color = 'lightgray'
             else:
                 color = 'red'
-            if (cur_track + new_track).count('-') == 1:
-                lhs_track, rhs_track = (ui.colorize(color, cur_track),
-                                        ui.colorize(color, new_track))
-            else:
-                color = 'red'
-                lhs_track, rhs_track = ui.color_diff_suffix(cur_track,
-                                                            new_track)
-            templ = (ui.colorize(color, u' (#') + u'{0}' +
-                     ui.colorize(color, u')'))
-            lhs += templ.format(lhs_track)
-            rhs += templ.format(rhs_track)
+            templ = ui.colorize(color, u' (#{0})')
+            lhs += templ.format(cur_track)
+            rhs += templ.format(new_track)
             lhs_width += len(cur_track) + 4
 
         # Length change.
@@ -337,12 +329,9 @@ 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.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)
+            templ = ui.colorize('red', u' ({0})')
+            lhs += templ.format(cur_length)
+            rhs += templ.format(new_length)
             lhs_width += len(cur_length) + 3
 
         # Penalties.

docs/changelog.rst

@@ -24,6 +24,9 @@ Fixes:
   an argument.
 * :doc:`/plugins/play`: Remove the temporary .m3u file after sending it to
   the player.
+* The importer no longer tries to highlight partial differences in numeric
+  quantities (track numbers and durations), which was often confusing.
+
 
 1.3.8 (September 17, 2014)
 --------------------------