Re: Incremental updates to What's cooking

@@ -0,0 +1,182 @@
+#!/bin/sh
+#
+# Copyright (c) 2012 Zbigniew Jędrzejewski-Szmek
+#
+
+test_description='test --stat output of various commands'
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-terminal.sh
+
+# 120 character name
+name=aaaaaaaaaa
+name=$name$name$name$name$name$name$name$name$name$name$name$name
+test_expect_success 'preparation' '
+	>"$name" &&
+	git add "$name" &&
+	git commit -m message &&
+	echo a >"$name" &&
+	git commit -m message "$name"
+'
+
+while read cmd args
+do
+	cat >expect <<-'EOF'
+	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
+	EOF
+	test_expect_success "$cmd: a short graph bar does not extend to the full width" '
+		git $cmd $args >output &&
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+
+	cat >expect <<-'EOF'
+	 ...aaaaaaaaaaaaaaaaaaaaaa |    1 +
+	EOF
+	test_expect_success "$cmd --stat=width: name is chopped to leave room to the right of a short bar" '
+		git $cmd $args --stat=40 >output &&
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "$cmd --stat-width=width with long name" '
+		git $cmd $args --stat-width=40 >output &&
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+
+	cat >expect <<-'EOF'
+	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
+	EOF
+	test_expect_success "$cmd --stat=...,name-width with long name" '
+		git $cmd $args --stat=60,30 >output &&
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "$cmd --stat-name-width with long name" '
+		git $cmd $args --stat-name-width=30 >output &&
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+done <<\EOF
+format-patch -1 --stdout
+diff HEAD^ HEAD --stat
+show --stat
+log -1 --stat
+EOF
+
+
+test_expect_success 'preparation for big change tests' '
+	>abcd &&
+	git add abcd &&
+	git commit -m message &&
+	i=0 &&
+	while test $i -lt 1000
+	do
+		echo $i && i=$(($i + 1))
+	done >abcd &&
+	git commit -m message abcd
+'
+
+cat >expect80 <<'EOF'
+ abcd | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+EOF
+
+while read verb expect cmd args
+do
+	test_expect_success "$cmd $verb COLUMNS (big change)" '
+		COLUMNS=200 git $cmd $args >output
+		grep " | " output >actual &&
+		test_cmp "$expect" actual
+	'
+done <<\EOF
+ignores expect80 format-patch -1 --stdout
+ignores expect80 diff HEAD^ HEAD --stat
+ignores expect80 show --stat
+ignores expect80 log -1 --stat
+EOF
+
+cat >expect <<'EOF'
+ abcd | 1000 ++++++++++++++++++++++++++
+EOF
+while read cmd args
+do
+	test_expect_success "$cmd --stat=width with big change" '
+		git $cmd $args --stat=40 >output
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "$cmd --stat-width=width with big change" '
+		git $cmd $args --stat-width=40 >output
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+done <<\EOF
+format-patch -1 --stdout
+diff HEAD^ HEAD --stat
+show --stat
+log -1 --stat
+EOF
+
+test_expect_success 'preparation for long filename tests' '
+	cp abcd aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa &&
+	git add aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa &&
+	git commit -m message
+'
+
+cat >expect <<'EOF'
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 +++++
+EOF
+while read cmd args
+do
+	test_expect_success "$cmd --stat=width with big change and long name favors name part" '
+		git $cmd $args --stat-width=60 >output &&
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
+done <<\EOF
+format-patch -1 --stdout
+diff HEAD^ HEAD --stat
+show --stat
+log -1 --stat
+EOF
+
+cat >expect80 <<'EOF'
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++
+EOF
+while read verb expect cmd args
+do
+	test_expect_success "$cmd $verb COLUMNS (long filename)" '
+		COLUMNS=200 git $cmd $args >output
+		grep " | " output >actual &&
+		test_cmp "$expect" actual
+	'
+done <<\EOF
+ignores expect80 format-patch -1 --stdout
+ignores expect80 diff HEAD^ HEAD --stat
+ignores expect80 show --stat
+ignores expect80 log -1 --stat
+EOF
+
+cat >expect <<'EOF'
+ abcd | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+EOF
+test_expect_success 'merge --stat ignores COLUMNS (big change)' '
+	git checkout -b branch HEAD^^ &&
+	COLUMNS=100 git merge --stat --no-ff master^ >output &&
+	grep " | " output >actual
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++
+EOF
+test_expect_success 'merge --stat ignores COLUMNS (long filename)' '
+	COLUMNS=100 git merge --stat --no-ff master >output &&
+	grep " | " output >actual
+	test_cmp expect actual
+'
+
+test_done

@@ -285,6 +285,9 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	/* Otherwise, we are doing the usual "git" diff */
 	rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 
+	/* Scale to real terminal size */
+	rev.diffopt.stat_width = -1;
+
 	/* Default to let external and textconv be used */
 	DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
 	DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);

@@ -1343,7 +1343,10 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		line_prefix = msg->buf;
 	}
 
-	width = options->stat_width ? options->stat_width : 80;
+	if (options->stat_width == -1)
+		width = term_columns();
+	else
+		width = options->stat_width ? options->stat_width : 80;
 	name_width = options->stat_name_width ? options->stat_name_width : 50;
 	count = options->stat_count ? options->stat_count : data->nr;
 

@@ -83,6 +83,10 @@ cat >expect80 <<'EOF'
  abcd | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 EOF
 
+cat >expect200 <<'EOF'
+ abcd | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+EOF
+
 while read verb expect cmd args
 do
 	test_expect_success "$cmd $verb COLUMNS (big change)" '

@@ -92,7 +96,7 @@ do
 	'
 done <<\EOF
 ignores expect80 format-patch -1 --stdout
-ignores expect80 diff HEAD^ HEAD --stat
+respects expect200 diff HEAD^ HEAD --stat
 ignores expect80 show --stat
 ignores expect80 log -1 --stat
 EOF

@@ -146,6 +150,9 @@ EOF
 cat >expect80 <<'EOF'
  ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++
 EOF
+cat >expect200 <<'EOF'
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+EOF
 while read verb expect cmd args
 do
 	test_expect_success "$cmd $verb COLUMNS (long filename)" '

@@ -155,7 +162,7 @@ do
 	'
 done <<\EOF
 ignores expect80 format-patch -1 --stdout
-ignores expect80 diff HEAD^ HEAD --stat
+respects expect200 diff HEAD^ HEAD --stat
 ignores expect80 show --stat
 ignores expect80 log -1 --stat
 EOF

@@ -447,6 +447,8 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	rev.diff = 1;
 	rev.always_show_header = 1;
 	rev.no_walk = 1;
+	rev.diffopt.stat_width = -1; 	/* Scale to real terminal size */
+
 	memset(&opt, 0, sizeof(opt));
 	opt.def = "HEAD";
 	opt.tweak = show_rev_tweak_rev;

@@ -97,7 +97,7 @@ do
 done <<\EOF
 ignores expect80 format-patch -1 --stdout
 respects expect200 diff HEAD^ HEAD --stat
-ignores expect80 show --stat
+respects expect200 show --stat
 ignores expect80 log -1 --stat
 EOF
 

@@ -163,7 +163,7 @@ do
 done <<\EOF
 ignores expect80 format-patch -1 --stdout
 respects expect200 diff HEAD^ HEAD --stat
-ignores expect80 show --stat
+respects expect200 show --stat
 ignores expect80 log -1 --stat
 EOF
 

@@ -77,6 +77,7 @@ static void cmd_log_init_defaults(struct rev_info *rev)
 		get_commit_format(fmt_pretty, rev);
 	rev->verbose_header = 1;
 	DIFF_OPT_SET(&rev->diffopt, RECURSIVE);
+	rev->diffopt.stat_width = -1; /* use full terminal width */
 	rev->abbrev_commit = default_abbrev_commit;
 	rev->show_root_diff = default_show_root;
 	rev->subject_prefix = fmt_patch_subject_prefix;

@@ -98,7 +98,7 @@ done <<\EOF
 ignores expect80 format-patch -1 --stdout
 respects expect200 diff HEAD^ HEAD --stat
 respects expect200 show --stat
-ignores expect80 log -1 --stat
+respects expect200 log -1 --stat
 EOF
 
 cat >expect <<'EOF'

@@ -164,7 +164,7 @@ done <<\EOF
 ignores expect80 format-patch -1 --stdout
 respects expect200 diff HEAD^ HEAD --stat
 respects expect200 show --stat
-ignores expect80 log -1 --stat
+respects expect200 log -1 --stat
 EOF
 
 cat >expect <<'EOF'

@@ -399,6 +399,7 @@ static void finish(struct commit *head_commit,
 	if (new_head && show_diffstat) {
 		struct diff_options opts;
 		diff_setup(&opts);
+		opts.stat_width = -1; /* use full terminal width */
 		opts.output_format |=
 			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 		opts.detect_rename = DIFF_DETECT_RENAME;

@@ -168,9 +168,9 @@ respects expect200 log -1 --stat
 EOF
 
 cat >expect <<'EOF'
- abcd | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ abcd | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 EOF
-test_expect_success 'merge --stat ignores COLUMNS (big change)' '
+test_expect_success 'merge --stat respects COLUMNS (big change)' '
 	git checkout -b branch HEAD^^ &&
 	COLUMNS=100 git merge --stat --no-ff master^ >output &&
 	grep " | " output >actual

@@ -178,9 +178,9 @@ test_expect_success 'merge --stat ignores COLUMNS (big change)' '
 '
 
 cat >expect <<'EOF'
- ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++++++++++++++++++++++
 EOF
-test_expect_success 'merge --stat ignores COLUMNS (long filename)' '
+test_expect_success 'merge --stat respects COLUMNS (long filename)' '
 	COLUMNS=100 git merge --stat --no-ff master >output &&
 	grep " | " output >actual
 	test_cmp expect actual

@@ -53,13 +53,15 @@ endif::git-format-patch[]
 	Generate a diff using the "patience diff" algorithm.
 
 --stat[=<width>[,<name-width>[,<count>]]]::
-	Generate a diffstat.  You can override the default
-	output width for 80-column terminal by `--stat=<width>`.
-	The width of the filename part can be controlled by
-	giving another width to it separated by a comma.
+	Generate a diffstat. By default, as much space as necessary
+	will be used for the filename part, and the rest for
+	the graph part. Maximum width defaults to terminal width,
+	or 80 columns if not connected to a terminal, and can be
+	overriden by `<width>`. The width of the filename part can be
+	limited by giving another width `<name-width>` after a comma.
 	By giving a third parameter `<count>`, you can limit the
-	output to the first `<count>` lines, followed by
-	`...` if there are more.
+	output to the first `<count>` lines, followed by `...` if
+	there are more.
 +
 These parameters can also be set individually with `--stat-width=<width>`,
 `--stat-name-width=<name-width>` and `--stat-count=<count>`.

@@ -1329,7 +1329,7 @@ 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, count;
+	int width, name_width, graph_width, number_width = 4, count;
 	const char *reset, *add_c, *del_c;
 	const char *line_prefix = "";
 	int extra_shown = 0;

@@ -1343,28 +1343,15 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		line_prefix = msg->buf;
 	}
 
-	if (options->stat_width == -1)
-		width = term_columns();
-	else
-		width = options->stat_width ? options->stat_width : 80;
-	name_width = options->stat_name_width ? options->stat_name_width : 50;
 	count = options->stat_count ? options->stat_count : data->nr;
 
-	/* Sanity: give at least 5 columns to the graph,
-	 * but leave at least 10 columns for the name.
-	 */
-	if (width < 25)
-		width = 25;
-	if (name_width < 10)
-		name_width = 10;
-	else if (width < name_width + 15)
-		name_width = width - 15;
-
-	/* Find the longest filename and max number of changes */
 	reset = diff_get_color_opt(options, DIFF_RESET);
 	add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 	del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 
+	/*
+	 * Find the longest filename and max number of changes
+	 */
 	for (i = 0; (i < count) && (i < data->nr); i++) {
 		struct diffstat_file *file = data->files[i];
 		uintmax_t change = file->added + file->deleted;

@@ -1385,19 +1372,62 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	}
 	count = i; /* min(count, data->nr) */
 
-	/* Compute the width of the graph part;
-	 * 10 is for one blank at the beginning of the line plus
-	 * " | count " between the name and the graph.
+	/*
+	 * We have width = stat_width or term_columns() columns total.
+	 * We want a maximum of min(max_len, stat_name_width) for the name part.
+	 * We also need 1 for " " and 4 + decimal_width(max_change)
+	 * for " | NNNN " and one the empty column at the end, altogether
+	 * 6 + decimal_width(max_change).
+	 *
+	 * If there's not enough space, we will use the smaller of
+	 * stat_name_width (if set) and 5/8*width for the filename,
+	 * and the rest for constant elements + graph part.
+	 * (5/8 gives 50 for filename and 30 for the constant parts + graph
+	 * for the standard terminal size).
 	 *
-	 * From here on, name_width is the width of the name area,
-	 * and width is the width of the graph area.
+	 * In other words: stat_width limits the maximum width, and
+	 * stat_name_width fixes the maximum width of the filename,
+	 * and is also used to divide available columns if there
+	 * aren't enough.
 	 */
-	name_width = (name_width < max_len) ? name_width : max_len;
-	if (width < (name_width + 10) + max_change)
-		width = width - (name_width + 10);
+
+	if (options->stat_width == -1)
+		width = term_columns();
 	else
-		width = max_change;
+		width = options->stat_width ? options->stat_width : 80;
 
+	/*
+	 * 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;
+
+	/*
+	 * First assign sizes that are wanted, ignoring available width.
+	 */
+	graph_width = max_change;
+	name_width = (options->stat_name_width > 0 &&
+		      options->stat_name_width < max_len) ?
+		options->stat_name_width : max_len;
+
+	/*
+	 * Adjust adjustable widths not to exceed maximum width
+	 */
+	if (name_width + number_width + 6 + graph_width > width) {
+		if (graph_width > width * 3/8 - number_width - 6)
+			graph_width = width * 3/8 - number_width - 6;
+		if (name_width > width - number_width - 6 - graph_width)
+			name_width = width - number_width - 6 - graph_width;
+		else
+			graph_width = width - number_width - 6 - name_width;
+	}
+
+	/*
+	 * From here name_width is the width of the name area,
+	 * and graph_width is the width of the graph area.
+	 * max_change is used to scale graph properly.
+	 */
 	for (i = 0; i < count; i++) {
 		const char *prefix = "";
 		char *name = data->files[i]->print_name;

@@ -1453,18 +1483,18 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 		adds += add;
 		dels += del;
 
-		if (width <= max_change) {
+		if (graph_width <= max_change) {
 			int total = add + del;
 
-			total = scale_linear(add + del, width, max_change);
+			total = scale_linear(add + del, graph_width, max_change);
 			if (total < 2 && add && del)
 				/* width >= 2 due to the sanity check */
 				total = 2;
 			if (add < del) {
-				add = scale_linear(add, width, max_change);
+				add = scale_linear(add, graph_width, max_change);
 				del = total - add;
 			} else {
-				del = scale_linear(del, width, max_change);
+				del = scale_linear(del, graph_width, max_change);
 				add = total - del;
 			}
 		}

@@ -22,18 +22,18 @@ test_expect_success 'preparation' '
 while read cmd args
 do
 	cat >expect <<-'EOF'
-	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
+	 ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
 	EOF
-	test_expect_success "$cmd: a short graph bar does not extend to the full width" '
+	test_expect_success "$cmd: small change with long name gives more space to the name" '
 		git $cmd $args >output &&
 		grep " | " output >actual &&
 		test_cmp expect actual
 	'
 
 	cat >expect <<-'EOF'
-	 ...aaaaaaaaaaaaaaaaaaaaaa |    1 +
+	 ...aaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
 	EOF
-	test_expect_success "$cmd --stat=width: name is chopped to leave room to the right of a short bar" '
+	test_expect_success "$cmd --stat=width: a long name is given more room when the bar is short" '
 		git $cmd $args --stat=40 >output &&
 		grep " | " output >actual &&
 		test_cmp expect actual

@@ -131,11 +131,11 @@ test_expect_success 'preparation for long filename tests' '
 '
 
 cat >expect <<'EOF'
- ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 +++++
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++
 EOF
 while read cmd args
 do
-	test_expect_success "$cmd --stat=width with big change and long name favors name part" '
+	test_expect_success "$cmd --stat=width with big change is more balanced" '
 		git $cmd $args --stat-width=60 >output &&
 		grep " | " output >actual &&
 		test_cmp expect actual

@@ -151,7 +151,7 @@ cat >expect80 <<'EOF'
  ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++
 EOF
 cat >expect200 <<'EOF'
- ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 EOF
 while read verb expect cmd args
 do

@@ -178,7 +178,7 @@ test_expect_success 'merge --stat respects COLUMNS (big change)' '
 '
 
 cat >expect <<'EOF'
- ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 ++++++++++++++++++++++++++++++++++++++++
+ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1000 +++++++++++++++++++++++++++++++++++++++
 EOF
 test_expect_success 'merge --stat respects COLUMNS (long filename)' '
 	COLUMNS=100 git merge --stat --no-ff master >output &&

@@ -101,6 +101,25 @@ respects expect200 show --stat
 respects expect200 log -1 --stat
 EOF
 
+cat >expect40 <<'EOF'
+ abcd | 1000 ++++++++++++++++++++++++++
+EOF
+
+while read verb expect cmd args
+do
+	test_expect_success "$cmd $verb not enough COLUMNS (big change)" '
+		COLUMNS=40 git $cmd $args >output
+		grep " | " output >actual &&
+		test_cmp "$expect" actual
+	'
+done <<\EOF
+ignores expect80 format-patch -1 --stdout
+respects expect40 diff HEAD^ HEAD --stat
+respects expect40 show --stat
+respects expect40 log -1 --stat
+EOF
+
+
 cat >expect <<'EOF'
  abcd | 1000 ++++++++++++++++++++++++++
 EOF

@@ -59,6 +59,8 @@ endif::git-format-patch[]
 	or 80 columns if not connected to a terminal, and can be
 	overriden by `<width>`. The width of the filename part can be
 	limited by giving another width `<name-width>` after a comma.
+	The width of the graph part can be limited by using
+	`--stat-graph-width=<width>`.
 	By giving a third parameter `<count>`, you can limit the
 	output to the first `<count>` lines, followed by `...` if
 	there are more.

@@ -1375,13 +1375,15 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	/*
 	 * We have width = stat_width or term_columns() columns total.
 	 * We want a maximum of min(max_len, stat_name_width) for the name part.
+	 * We want a maximum of min(max_change, stat_graph_width) for the +- part.
 	 * We also need 1 for " " and 4 + decimal_width(max_change)
 	 * for " | NNNN " and one the empty column at the end, altogether
 	 * 6 + decimal_width(max_change).
 	 *
 	 * If there's not enough space, we will use the smaller of
 	 * stat_name_width (if set) and 5/8*width for the filename,
-	 * and the rest for constant elements + graph part.
+	 * and the rest for constant elements + graph part, but no more
+	 * than stat_graph_width for the graph part.
 	 * (5/8 gives 50 for filename and 30 for the constant parts + graph
 	 * for the standard terminal size).
 	 *

@@ -1406,7 +1408,9 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	/*
 	 * First assign sizes that are wanted, ignoring available width.
 	 */
-	graph_width = max_change;
+	graph_width = (options->stat_graph_width &&
+		       options->stat_graph_width < max_change) ?
+		options->stat_graph_width : max_change;
 	name_width = (options->stat_name_width > 0 &&
 		      options->stat_name_width < max_len) ?
 		options->stat_name_width : max_len;

@@ -1417,6 +1421,9 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	if (name_width + number_width + 6 + graph_width > width) {
 		if (graph_width > width * 3/8 - number_width - 6)
 			graph_width = width * 3/8 - number_width - 6;
+		if (options->stat_graph_width &&
+		    graph_width > options->stat_graph_width)
+			graph_width = options->stat_graph_width;
 		if (name_width > width - number_width - 6 - graph_width)
 			name_width = width - number_width - 6 - graph_width;
 		else

@@ -3289,6 +3296,7 @@ static int stat_opt(struct diff_options *options, const char **av)
 	char *end;
 	int width = options->stat_width;
 	int name_width = options->stat_name_width;
+	int graph_width = options->stat_graph_width;
 	int count = options->stat_count;
 	int argcount = 1;
 

@@ -3317,6 +3325,16 @@ static int stat_opt(struct diff_options *options, const char **av)
 				name_width = strtoul(av[1], &end, 10);
 				argcount = 2;
 			}
+		} else if (!prefixcmp(arg, "-graph-width")) {
+			arg += strlen("-graph-width");
+			if (*arg == '=')
+				graph_width = strtoul(arg + 1, &end, 10);
+			else if (!*arg && !av[1])
+				die("Option '--stat-graph-width' requires a value");
+			else if (!*arg) {
+				graph_width = strtoul(av[1], &end, 10);
+				argcount = 2;
+			}
 		} else if (!prefixcmp(arg, "-count")) {
 			arg += strlen("-count");
 			if (*arg == '=')

@@ -3342,6 +3360,7 @@ static int stat_opt(struct diff_options *options, const char **av)
 		return 0;
 	options->output_format |= DIFF_FORMAT_DIFFSTAT;
 	options->stat_name_width = name_width;
+	options->stat_graph_width = graph_width;
 	options->stat_width = width;
 	options->stat_count = count;
 	return argcount;

@@ -129,6 +129,7 @@ struct diff_options {
 
 	int stat_width;
 	int stat_name_width;
+	int stat_graph_width;
 	int stat_count;
 	const char *word_regex;
 	enum diff_words_type word_diff;

@@ -136,6 +136,12 @@ do
 		grep " | " output >actual &&
 		test_cmp expect actual
 	'
+
+	test_expect_success "$cmd --stat-graph--width with big change" '
+		git $cmd $args --stat-graph-width=26 >output
+		grep " | " output >actual &&
+		test_cmp expect actual
+	'
 done <<\EOF
 format-patch -1 --stdout
 diff HEAD^ HEAD --stat

@@ -52,6 +52,10 @@ directories with less than 10% of the total amount of changed files,
 and accumulating child directory counts in the parent directories:
 `files,10,cumulative`.
 
+diff.statGraphWidth::
+	Limit the width of the graph part in --stat output. If set, applies
+	to all commands generating --stat outuput except format-patch.
+
 diff.external::
 	If this config variable is set, diff generation is not
 	performed using the internal diff machinery, but using the

@@ -54,13 +54,15 @@ endif::git-format-patch[]
 
 --stat[=<width>[,<name-width>[,<count>]]]::
 	Generate a diffstat. By default, as much space as necessary
-	will be used for the filename part, and the rest for
-	the graph part. Maximum width defaults to terminal width,
-	or 80 columns if not connected to a terminal, and can be
-	overriden by `<width>`. The width of the filename part can be
-	limited by giving another width `<name-width>` after a comma.
-	The width of the graph part can be limited by using
-	`--stat-graph-width=<width>`.
+	will be used for the filename part, and the rest for the graph
+	part. Maximum width defaults to terminal width, or 80 columns
+	if not connected to a terminal, and can be overriden by
+	`<width>`. The width of the filename part can be limited by
+	giving another width `<name-width>` after a comma. The width
+	of the graph part can be limited by using
+	`--stat-graph-width=<width>` (affects all commands generating
+	a stat graph) or by setting `diff.statGraphWidth=<width>`
+	(does not affect `git format-patch`).
 	By giving a third parameter `<count>`, you can limit the
 	output to the first `<count>` lines, followed by `...` if
 	there are more.

@@ -285,8 +285,9 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	/* Otherwise, we are doing the usual "git" diff */
 	rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 
-	/* Scale to real terminal size */
+	/* Scale to real terminal size and respect statGraphWidth config */
 	rev.diffopt.stat_width = -1;
+	rev.diffopt.stat_graph_width = -1;
 
 	/* Default to let external and textconv be used */
 	DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);

@@ -78,6 +78,7 @@ static void cmd_log_init_defaults(struct rev_info *rev)
 	rev->verbose_header = 1;
 	DIFF_OPT_SET(&rev->diffopt, RECURSIVE);
 	rev->diffopt.stat_width = -1; /* use full terminal width */
+	rev->diffopt.stat_graph_width = -1; /* respect statGraphWidth config */
 	rev->abbrev_commit = default_abbrev_commit;
 	rev->show_root_diff = default_show_root;
 	rev->subject_prefix = fmt_patch_subject_prefix;

@@ -400,6 +400,7 @@ static void finish(struct commit *head_commit,
 		struct diff_options opts;
 		diff_setup(&opts);
 		opts.stat_width = -1; /* use full terminal width */
+		opts.stat_graph_width = -1; /* respect statGraphWidth config */
 		opts.output_format |=
 			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 		opts.detect_rename = DIFF_DETECT_RENAME;

@@ -2118,6 +2118,7 @@ _git_config ()
 		core.whitespace
 		core.worktree
 		diff.autorefreshindex
+		diff.statGraphWidth
 		diff.external
 		diff.ignoreSubmodules
 		diff.mnemonicprefix

@@ -31,6 +31,7 @@ static const char *external_diff_cmd_cfg;
 int diff_auto_refresh_index = 1;
 static int diff_mnemonic_prefix;
 static int diff_no_prefix;
+static int diff_stat_graph_width;
 static int diff_dirstat_permille_default = 30;
 static struct diff_options default_diff_options;
 

@@ -156,6 +157,10 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		diff_no_prefix = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "diff.statgraphwidth")) {
+		diff_stat_graph_width = git_config_int(var, value);
+		return 0;
+	}
 	if (!strcmp(var, "diff.external"))
 		return git_config_string(&external_diff_cmd_cfg, var, value);
 	if (!strcmp(var, "diff.wordregex"))

@@ -1398,6 +1403,9 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options)
 	else
 		width = options->stat_width ? options->stat_width : 80;
 
+	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

@@ -112,6 +112,12 @@ do
 		grep " | " output >actual &&
 		test_cmp "$expect" actual
 	'
+
+	test_expect_success "$cmd $verb statGraphWidth config" '
+		git -c diff.statGraphWidth=26 $cmd $args >output
+		grep " | " output >actual &&
+		test_cmp "$expect" actual
+	'
 done <<\EOF
 ignores expect80 format-patch -1 --stdout
 respects expect40 diff HEAD^ HEAD --stat

@@ -1 +1 @@
- ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa |    1 +

@@ -17,6 +17,7 @@ test_expect_success 'preparation' '
 	git commit -m message &&
 	echo a >"$name" &&
 	git commit -m message "$name"
+	sane_unset COLUMNS
 '
 
 while read cmd args

@@ -46,7 +46,7 @@ EDITOR=:
 # /usr/xpg4/bin/sh and /bin/ksh to bail out.  So keep the unsets
 # deriving from the command substitution clustered with the other
 # ones.
-unset VISUAL EMAIL LANGUAGE $(perl -e '
+unset VISUAL EMAIL LANGUAGE COLUMNS $(perl -e '
 	my @env = keys %ENV;
 	my $ok = join("|", qw(
 		TRACE