[PATCH] format-patch: set diffstat width to 70 instead of default 80

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Patches or cover letters generated by format-patch are meant to be
exchanged as emails, most of the time. And since it's generally agreed
that text in mails should be wrapped around 70 columns or so, make sure
these diffstat follow the convention.

I noticed this when I quoted a diffstat line [1]. Should we do something
like this? diffstat is rarely quoted though so perhaps the stat width
should be something like 75.

t4052 fails but I don't think it's worth fixing until it's clear if it's
worth doing this.

[1] https://public-inbox.org/git/20180122121426.GD5980@ash/T/#u

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/log.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/builtin/log.c b/builtin/log.c
index 14fdf39165..6be79656c5 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1061,6 +1061,7 @@ static void make_cover_letter(struct rev_info *rev, int use_stdout,
 
 	memcpy(&opts, &rev->diffopt, sizeof(opts));
 	opts.output_format = DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
+	opts.diffopt.stat_width = 70;
 
 	diff_setup_done(&opts);
 
@@ -1611,9 +1612,12 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		die(_("--check does not make sense"));
 
 	if (!use_patch_format &&
-		(!rev.diffopt.output_format ||
-		 rev.diffopt.output_format == DIFF_FORMAT_PATCH))
+	    (!rev.diffopt.output_format ||
+	     rev.diffopt.output_format == DIFF_FORMAT_PATCH)) {
 		rev.diffopt.output_format = DIFF_FORMAT_DIFFSTAT | DIFF_FORMAT_SUMMARY;
+		if (!rev.diffopt.stat_width)
+			rev.diffopt.stat_width = 70;
+	}
 
 	/* Always generate a patch */
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
-- 
2.16.0.47.g3d9b0fac3a