Merge branch 'zj/diff-stat-smaller-num-columns'

Spend only minimum number of columns necessary to show the number of lines
in the output from "diff --stat", instead of always allocating 4 columns
even when showing changes that are much smaller than 1000 lines.

By Zbigniew Jędrzejewski-Szmek
* zj/diff-stat-smaller-num-columns:
  diff --stat: use less columns for change counts

diff.c

@@ -1443,8 +1443,8 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 {
 	int i, len, add, del, adds = 0, dels = 0;
 	uintmax_t max_change = 0, max_len = 0;
-	int total_files = data->nr;
-	int width, name_width, graph_width, number_width = 4, count;
+	int total_files = data->nr, count;
+	int width, name_width, graph_width, number_width = 0, bin_width = 0;
 	const char *reset, *add_c, *del_c;
 	const char *line_prefix = "";
 	int extra_shown = 0;
@@ -1480,8 +1480,21 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		if (max_len < len)
 			max_len = len;
 
-		if (file->is_binary || file->is_unmerged)
+		if (file->is_unmerged) {
+			/* "Unmerged" is 8 characters */
+			bin_width = bin_width < 8 ? 8 : bin_width;
 			continue;
+		}
+		if (file->is_binary) {
+			/* "Bin XXX -> YYY bytes" */
+			int w = 14 + decimal_width(file->added)
+				+ decimal_width(file->deleted);
+			bin_width = bin_width < w ? w : bin_width;
+			/* Display change counts aligned with "Bin" */
+			number_width = 3;
+			continue;
+		}
+
 		if (max_change < change)
 			max_change = change;
 	}
@@ -1506,12 +1519,22 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	 * stat_name_width fixes the maximum width of the filename,
 	 * and is also used to divide available columns if there
 	 * aren't enough.
+	 *
+	 * Binary files are displayed with "Bin XXX -> YYY bytes"
+	 * instead of the change count and graph. This part is treated
+	 * similarly to the graph part, except that it is not
+	 * "scaled". If total width is too small to accomodate the
+	 * guaranteed minimum width of the filename part and the
+	 * separators and this message, this message will "overflow"
+	 * making the line longer than the maximum width.
 	 */
 
 	if (options->stat_width == -1)
 		width = term_columns() - options->output_prefix_length;
 	else
 		width = options->stat_width ? options->stat_width : 80;
+	number_width = decimal_width(max_change) > number_width ?
+		decimal_width(max_change) : number_width;
 
 	if (options->stat_graph_width == -1)
 		options->stat_graph_width = diff_stat_graph_width;
@@ -1525,10 +1548,14 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 
 	/*
 	 * First assign sizes that are wanted, ignoring available width.
+	 * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
+	 * starting from "XXX" should fit in graph_width.
 	 */
-	graph_width = (options->stat_graph_width &&
-		       options->stat_graph_width < max_change) ?
-		options->stat_graph_width : max_change;
+	graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
+	if (options->stat_graph_width &&
+	    options->stat_graph_width < graph_width)
+		graph_width = options->stat_graph_width;
+
 	name_width = (options->stat_name_width > 0 &&
 		      options->stat_name_width < max_len) ?
 		options->stat_name_width : max_len;
@@ -1587,7 +1614,7 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		if (data->files[i]->is_binary) {
 			fprintf(options->file, "%s", line_prefix);
 			show_name(options->file, prefix, name, len);
-			fprintf(options->file, "  Bin ");
+			fprintf(options->file, " %*s ", number_width, "Bin");
 			fprintf(options->file, "%s%"PRIuMAX"%s",
 				del_c, deleted, reset);
 			fprintf(options->file, " -> ");
@@ -1629,7 +1656,8 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		}
 		fprintf(options->file, "%s", line_prefix);
 		show_name(options->file, prefix, name, len);
-		fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
+		fprintf(options->file, " %*"PRIuMAX"%s",
+			number_width, added + deleted,
 			added + deleted ? " " : "");
 		show_graph(options->file, '+', add, add_c, reset);
 		show_graph(options->file, '-', del, del_c, reset);

t/t4012-diff-binary.sh

@@ -107,4 +107,23 @@ test_expect_success 'diff --no-index with binary creation' '
 	test_cmp expected actual
 '
 
+cat >expect <<EOF
+ binfile  |   Bin 0 -> 1026 bytes
+ textfile | 10000 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+EOF
+
+test_expect_success 'diff --stat with binary files and big change count' '
+	echo X | dd of=binfile bs=1k seek=1 &&
+	git add binfile &&
+	i=0 &&
+	while test $i -lt 10000; do
+		echo $i &&
+		i=$(($i + 1))
+	done >textfile &&
+	git add textfile &&
+	git diff --cached --stat binfile textfile >output &&
+	grep " | " output >actual &&
+	test_cmp expect actual
+'
+
 test_done

t/t4052-stat-output.sh

@@ -22,7 +22,7 @@ test_expect_success 'preparation' '
 while read cmd args
 do
 	cat >expect <<-'EOF'
-	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
+	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
 	EOF
 	test_expect_success "$cmd: small change with long name gives more space to the name" '
 		git $cmd $args >output &&
@@ -31,7 +31,7 @@ do
 	'
 
 	cat >expect <<-'EOF'
-	 ...aaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
+	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
 	EOF
 	test_expect_success "$cmd --stat=width: a long name is given more room when the bar is short" '
 		git $cmd $args --stat=40 >output &&