diff.c: use utf8_strwidth() instead of strlen() for display width

From: Chandra Pratap <[email protected]>

---
diff.c: use utf8_strwidth() instead of strlen() for display width

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1668%2FChand-ra%2Fdiff-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1668/Chand-ra/diff-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1668

 diff.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

index ccfa1fca0d0..02d60af6749 100644
@@ -2712,13 +2712,8 @@ 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);
+		width = term_columns() - utf8_strwidth(line_prefix);
 	else
 		width = options->stat_width ? options->stat_width : 80;
 	number_width = decimal_width(max_change) > number_width ?

base-commit: 2996f11c1d11ab68823f0939b6469dedc2b9ab90

gitgitgadget

I suspect that it is because it is not just that single strlen() call. The code assumed that byte count and display width were interchangeable, and use of strlen() there was merely an example. Starting there, the value returned by strlen() is treated as if it were interchangeable with a display width, and then later used to count how many bytes to trim from either end of the string so that the trimmed string would eventually fit a given display width, which means that the code to compute how much to trim (which is not that strlen() the patch in question is touching) would have to compute the reverse, i.e. "if we need to recover N display columns, how many bytes do we need to trim from that string?"