diff: leave NEEDWORK notes in show_stats() function

The previous step made an attempt to correctly compute display
columns allocated and padded different parts of diffstat output.
There are at least two known codepaths in the function that still
mixes up display widths and byte length that need to be fixed.

Signed-off-by: Junio C Hamano <[email protected]>

Author: gitster

diff.c

@@ -2675,6 +2675,11 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	 * making the line longer than the maximum width.
 	 */
 
+	/*
+	 * NEEDSWORK: line_prefix is often used for "log --graph" output
+	 * and contains ANSI-colored string.  utf8_strnwidth() should be
+	 * used to correctly count the display width instead of strlen().
+	 */
 	if (options->stat_width == -1)
 		width = term_columns() - strlen(line_prefix);
 	else
@@ -2750,6 +2755,16 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 			char *slash;
 			prefix = "...";
 			len -= 3;
+			/*
+			 * NEEDSWORK: (name_len - len) counts the display
+			 * width, which would be shorter than the byte
+			 * length of the corresponding substring.
+			 * Advancing "name" by that number of bytes does
+			 * *NOT* skip over that many columns, so it is
+			 * very likely that chomping the pathname at the
+			 * slash we will find starting from "name" will
+			 * leave the resulting string still too long.
+			 */
 			name += name_len - len;
 			slash = strchr(name, '/');
 			if (slash)