Re: [PATCH v2 1/1] diff.c: When appropriate, use utf8_strwidth()

Torsten Bögershausen [off-list ref] writes:

This is caused by the logic in diff.c:
  /*
   * Find the longest filename and max number of changes
   */
   for (i = 0; (i < count) && (i < data->nr); i++) {
       struct diffstat_file *file = data->files[i];
       [snip]
       len = utf8_strwidth(file->print_name);
       if (max_width < len)
          max_width = len;
// and later
    /*
     * From here name_width is the width of the name area,
     * and graph_width is the width of the graph area.
     * max_change is used to scale graph properly.
     */
    for (i = 0; i < count; i++) {
    /*
     * "scale" the filename
     */
     // TB: Which means either shortening it with ...
     // Or padding it, if needed, and here we need
     // another
     name_len = utf8_strwidth(name);

quoted

Besides, since the simple change from `strlen()` to `utf8_strwidth()` is
so different from changing `strbuf_addf(...)`, I would prefer to see them
split into two patches.

Hm, that is a possiblity. Seems to ease the burden for reviewers.

Another thing I remembered (this is a comment primarily on the
original I wrote based on 'all world is ASCII' mindset that led to
the use of strlen() as a display-width indicator) in the code is
that we "abbreviate" an overly long pathname and transform renames
that originally is in the a/b/c -> a/B/c form into a/{b->B}/c form,
and IIRC they are all byte based.  The latter may be OK because the
transformation is limited to '/' boundary, but the former may chomp
a single multi-byte letter in the middle, which would need to be
corrected as a part of this change.