graph: add --[no-]graph-indent and log.graphIndent

Some users may prefer to not have graph indentation.

Add "log.graphIndent" config variable to graph_read_config() to read the
default preference. By default is graph indentation is true.

Add --graph-indent and --no-graph-indent options to overwrite the
default preference.

Signed-off-by: Pablo Sabater <pabloosabaterr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config/log.adoc

@@ -59,6 +59,10 @@ This is the same as the `--decorate` option of the `git log`.
 	A list of colors, separated by commas, that can be used to draw
 	history lines in `git log --graph`.
 
+`log.graphIndent`::
+	If `true`, indent visual roots when rendering the graphs with `--graph`.
+	Set true by default. It can be overriden with `--[no-]graph-indent`.
+
 `log.showRoot`::
 	If true, the initial commit will be shown as a big creation event.
 	This is equivalent to a diff against an empty tree.

Documentation/rev-list-options.adoc

@@ -1269,6 +1269,14 @@ This implies the `--topo-order` option by default, but the
 	By default it is set to 0 (no limit), zero and negative values
 	are ignored and treated as no limit.
 
+`--no-graph-indent`::
+`--graph-indent`::
+	When used with `--graph`, indent visual roots (commits with no parents
+	or whose parents are not shown) to differentiate them from commits that
+	are vertically adjacent but unrelated. Enabled by default. Use
+	`--no-graph-indent` to disable or set `log.graphIndent` to set a
+	default preference.
+
 ifdef::git-rev-list[]
 `--count`::
 	Print a number stating how many commits would have been

graph.c

@@ -419,6 +419,8 @@ void graph_setup_line_prefix(struct diff_options *diffopt)
 
 static void graph_read_config(struct rev_info *revs)
 {
+	int val;
+
 	if (!column_colors) {
 		char *string;
 		if (repo_config_get_string(revs->repo, "log.graphcolors", &string)) {
@@ -435,6 +437,9 @@ static void graph_read_config(struct rev_info *revs)
 						custom_colors.nr - 1);
 		}
 	}
+
+	if (!repo_config_get_bool(revs->repo, "log.graphIndent", &val))
+		revs->no_graph_indent = !val;
 }
 
 struct git_graph *graph_init(struct rev_info *opt)
@@ -999,7 +1004,8 @@ static void graph_peek_next_visible(struct git_graph *graph,
 static int graph_needs_pre_root_line(struct git_graph *graph)
 {
 	return graph->commit_in_columns && graph->is_visual_root &&
-	       graph->num_columns > 0 && !graph->visual_root_cascade;
+	       graph->num_columns > 0 && !graph->visual_root_cascade &&
+	       !graph->revs->no_graph_indent;
 }
 
 void graph_update(struct git_graph *graph, struct commit *commit)
@@ -1344,7 +1350,7 @@ static void graph_output_commit_line(struct git_graph *graph, struct graph_line
 
 		if (col_commit == graph->commit) {
 			seen_this = 1;
-			if (graph->is_visual_root) {
+			if (graph->is_visual_root && !graph->revs->no_graph_indent) {
 				int depth = graph->visual_root_depth;
 				/*
 				 * Each visual column is 2 characters wide.

revision.c

@@ -2627,6 +2627,12 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->graph = NULL;
 	} else if (skip_prefix(arg, "--graph-lane-limit=", &optarg)) {
 		revs->graph_max_lanes = parse_count(optarg);
+	} else if (!strcmp(arg, "--graph-indent")) {
+		revs->no_graph_indent = 0;
+		revs->graph_indent_set = 1;
+	} else if (!strcmp(arg, "--no-graph-indent")) {
+		revs->no_graph_indent = 1;
+		revs->graph_indent_set = 1;
 	} else if (!strcmp(arg, "--encode-email-headers")) {
 		revs->encode_email_headers = 1;
 	} else if (!strcmp(arg, "--no-encode-email-headers")) {
@@ -3201,6 +3207,9 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	if (revs->graph_max_lanes > 0 && !revs->graph)
 		die(_("the option '%s' requires '%s'"), "--graph-lane-limit", "--graph");
 
+	if (revs->graph_indent_set && !revs->graph)
+		die(_("the option '%s' requires '%s'"), "--[no-]graph-indent", "--graph");
+
 	if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
 		die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
 

revision.h

@@ -314,6 +314,8 @@ struct rev_info {
 	/* Display history graph */
 	struct git_graph *graph;
 	int graph_max_lanes;
+	unsigned int no_graph_indent:1;
+	unsigned int graph_indent_set:1;
 
 	/* special limits */
 	int skip_count;

t/t4218-log-graph-indentation.sh

@@ -540,4 +540,57 @@ test_expect_success 'visual root cascading gets wrapped after 4 columns' '
 	EOF
 '
 
+test_expect_success '--no-graph-indent disables indentation' '
+	lib_test_check_graph --no-graph-indent _58 _59 _60 _61 _62 _63 _64 _65 _66 _67 <<-\EOF
+	* 67_A
+	* 66_A
+	* 65_A
+	* 64_A
+	* 63_A
+	* 62_A
+	* 61_A
+	* 60_A
+	* 59_A
+	* 58_B
+	* 58_A
+	EOF
+'
+
+test_expect_success 'log.graphIndent config disables indentation' '
+	test_config log.graphIndent false &&
+	lib_test_check_graph _58 _59 _60 _61 _62 _63 _64 _65 _66 _67 <<-\EOF
+	* 67_A
+	* 66_A
+	* 65_A
+	* 64_A
+	* 63_A
+	* 62_A
+	* 61_A
+	* 60_A
+	* 59_A
+	* 58_B
+	* 58_A
+	EOF
+'
+
+test_expect_success '--graph-indent forces indentation when graph.indent is unset' '
+	test_config log.graphIndent false &&
+	lib_test_check_graph --graph-indent _58 _59 _60 _61 _62 _63 _64 _65 _66 _67 <<-\EOF
+	* 67_A
+	  * 66_A
+	    * 65_A
+	      * 64_A
+	* 63_A
+	  * 62_A
+	    * 61_A
+	      * 60_A
+	  * 59_A
+	* 58_B
+	* 58_A
+	EOF
+'
+
+# log.graphIndent unset and no --option (which activates graph indentation) is
+# the default state.
+
 test_done