diff --stat: add config option to limit filename width

Add new configuration option diff.statNameWidth=<width> that is equivalent
to the command-line option --stat-name-width=<width>, but it is ignored
by format-patch.  This follows the logic established by the already
existing configuration option diff.statGraphWidth=<width>.

Limiting the widths of names and graphs in the --stat output makes sense
for interactive work on wide terminals with many columns, hence the support
for these configuration options.  They don't affect format-patch because
it already adheres to the traditional 80-column standard.

Update the documentation and add more tests to cover new configuration
option diff.statNameWidth=<width>.  While there, perform a few minor code
and whitespace cleanups here and there, as spotted.

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/diff.c b/diff.c
index bccb018da4..353e3b2cc9 100644
--- a/diff.c
+++ b/diff.c
@@ -65,6 +65,7 @@ int diff_auto_refresh_index = 1;
 static int diff_mnemonic_prefix;
 static int diff_no_prefix;
 static int diff_relative;
+static int diff_stat_name_width;
 static int diff_stat_graph_width;
 static int diff_dirstat_permille_default = 30;
 static struct diff_options default_diff_options;
@@ -410,6 +411,10 @@ int git_diff_ui_config(const char *var, const char *value,
 		diff_relative = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "diff.statnamewidth")) {
+		diff_stat_name_width = git_config_int(var, value, ctx->kvi);
+		return 0;
+	}
 	if (!strcmp(var, "diff.statgraphwidth")) {
 		diff_stat_graph_width = git_config_int(var, value, ctx->kvi);
 		return 0;
@@ -2704,12 +2709,14 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	number_width = decimal_width(max_change) > number_width ?
 		decimal_width(max_change) : number_width;
 
+	if (options->stat_name_width == -1)
+		options->stat_name_width = diff_stat_name_width;
 	if (options->stat_graph_width == -1)
 		options->stat_graph_width = diff_stat_graph_width;
 
 	/*
-	 * Guarantee 3/8*16==6 for the graph part
-	 * and 5/8*16==10 for the filename part
+	 * Guarantee 3/8*16 == 6 for the graph part
+	 * and 5/8*16 == 10 for the filename part
 	 */
 	if (width < 16 + 6 + number_width)
 		width = 16 + 6 + number_width;