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>

Documentation/config/diff.txt

@@ -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.statNameWidth::
+	Limit the width of the filename part in --stat output. If set, applies
+	to all commands generating --stat output except format-patch.
+
 diff.statGraphWidth::
 	Limit the width of the graph part in --stat output. If set, applies
 	to all commands generating --stat output except format-patch.

Documentation/diff-options.txt

@@ -204,14 +204,15 @@ have to use `--diff-algorithm=default` option.
 	part. Maximum width defaults to terminal width, or 80 columns
 	if not connected to a terminal, and can be overridden 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.
+	giving another width `<name-width>` after a comma or by setting
+	`diff.statNameWidth=<width>`. The width of the graph part can be
+	limited by using `--stat-graph-width=<width>` or by setting
+	`diff.statGraphWidth=<width>`. Using `--stat` or
+	`--stat-graph-width` affects all commands generating a stat graph,
+	while setting `diff.statNameWidth` or `diff.statGraphWidth`
+	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.
 +
 These parameters can also be set individually with `--stat-width=<width>`,
 `--stat-name-width=<name-width>` and `--stat-count=<count>`.

builtin/diff.c

@@ -475,6 +475,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 
 	/* Set up defaults that will apply to both no-index and regular diffs. */
 	rev.diffopt.stat_width = -1;
+	rev.diffopt.stat_name_width = -1;
 	rev.diffopt.stat_graph_width = -1;
 	rev.diffopt.flags.allow_external = 1;
 	rev.diffopt.flags.allow_textconv = 1;

builtin/log.c

@@ -178,6 +178,7 @@ static void cmd_log_init_defaults(struct rev_info *rev)
 	rev->verbose_header = 1;
 	rev->diffopt.flags.recursive = 1;
 	rev->diffopt.stat_width = -1; /* use full terminal width */
+	rev->diffopt.stat_name_width = -1; /* respect statNameWidth config */
 	rev->diffopt.stat_graph_width = -1; /* respect statGraphWidth config */
 	rev->abbrev_commit = default_abbrev_commit;
 	rev->show_root_diff = default_show_root;

builtin/merge.c

@@ -467,6 +467,7 @@ static void finish(struct commit *head_commit,
 		struct diff_options opts;
 		repo_diff_setup(the_repository, &opts);
 		opts.stat_width = -1; /* use full terminal width */
+		opts.stat_name_width = -1; /* respect statNameWidth config */
 		opts.stat_graph_width = -1; /* respect statGraphWidth config */
 		opts.output_format |=
 			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;

builtin/rebase.c

@@ -1804,6 +1804,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		/* We want color (if set), but no pager */
 		repo_diff_setup(the_repository, &opts);
 		opts.stat_width = -1; /* use full terminal width */
+		opts.stat_name_width = -1; /* respect statNameWidth config */
 		opts.stat_graph_width = -1; /* respect statGraphWidth config */
 		opts.output_format |=
 			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;

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;

graph.c

@@ -339,7 +339,6 @@ void graph_setup_line_prefix(struct diff_options *diffopt)
 		diffopt->output_prefix = diff_output_prefix_callback;
 }
 
-
 struct git_graph *graph_init(struct rev_info *opt)
 {
 	struct git_graph *graph = xmalloc(sizeof(struct git_graph));

t/t4052-stat-output.sh

@@ -49,12 +49,41 @@ log -1 --stat
 EOF
 
 cat >expect.60 <<-'EOF'
- ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
 EOF
 cat >expect.6030 <<-'EOF'
  ...aaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
 EOF
-cat >expect2.60 <<-'EOF'
+while read verb expect cmd args
+do
+	# No width limit applied when statNameWidth is ignored
+	case "$expect" in expect72|expect.6030)
+		test_expect_success "$cmd $verb statNameWidth config with long name" '
+			git -c diff.statNameWidth=30 $cmd $args >output &&
+			grep " | " output >actual &&
+			test_cmp $expect actual
+		';;
+	esac
+	# Maximum width limit still applied when statNameWidth is ignored
+	case "$expect" in expect.60|expect.6030)
+		test_expect_success "$cmd --stat=width $verb statNameWidth config with long name" '
+			git -c diff.statNameWidth=30 $cmd $args --stat=60 >output &&
+			grep " | " output >actual &&
+			test_cmp $expect actual
+		';;
+	esac
+done <<\EOF
+ignores expect72 format-patch -1 --stdout
+ignores expect.60 format-patch -1 --stdout
+respects expect.6030 diff HEAD^ HEAD --stat
+respects expect.6030 show --stat
+respects expect.6030 log -1 --stat
+EOF
+
+cat >expect.40 <<-'EOF'
+ ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
+EOF
+cat >expect2.40 <<-'EOF'
  ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
  ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaa | 1 +
 EOF
@@ -67,16 +96,16 @@ do
 	test_expect_success "$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.60 actual
+		test_cmp $expect.40 actual
 	'
 
 	test_expect_success "$cmd --stat-width=width with long name" '
 		git $cmd $args --stat-width=40 >output &&
 		grep " | " output >actual &&
-		test_cmp $expect.60 actual
+		test_cmp $expect.40 actual
 	'
 
-	test_expect_success "$cmd --stat=...,name-width with long name" '
+	test_expect_success "$cmd --stat=width,name-width with long name" '
 		git $cmd $args --stat=60,30 >output &&
 		grep " | " output >actual &&
 		test_cmp $expect.6030 actual
@@ -94,7 +123,6 @@ expect show --stat
 expect log -1 --stat
 EOF
 
-
 test_expect_success 'preparation for big change tests' '
 	>abcd &&
 	git add abcd &&
@@ -207,7 +235,6 @@ respects expect40 show --stat
 respects expect40 log -1 --stat
 EOF
 
-
 cat >expect <<'EOF'
  abcd | 1000 ++++++++++++++++++++++++++
 EOF