Merge branch 'nd/log-graph-configurable-colors'

Some people feel the default set of colors used by "git log --graph"
rather limiting.  A mechanism to customize the set of colors has
been introduced.

* nd/log-graph-configurable-colors:
  document behavior of empty color name
  color_parse_mem: allow empty color spec
  log --graph: customize the graph lines with config log.graphColors
  color.c: trim leading spaces in color_parse_mem()
  color.c: fix color_parse_mem() with value_len == 0

Documentation/config.txt

@@ -170,6 +170,9 @@ The position of any attributes with respect to the colors
 be turned off by prefixing them with `no` or `no-` (e.g., `noreverse`,
 `no-ul`, etc).
 +
+An empty color string produces no color effect at all. This can be used
+to avoid coloring specific elements without disabling color entirely.
++
 For git's pre-defined color slots, the attributes are meant to be reset
 at the beginning of each item in the colored output. So setting
 `color.decorate.branch` to `black` will paint that branch name in a
@@ -2036,6 +2039,10 @@ log.follow::
 	i.e. it cannot be used to follow multiple files and does not work well
 	on non-linear history.
 
+log.graphColors::
+	A list of colors, separated by commas, that can be used to draw
+	history lines in `git log --graph`.
+
 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.

color.c

@@ -207,7 +207,17 @@ int color_parse_mem(const char *value, int value_len, char *dst)
 	struct color fg = { COLOR_UNSPECIFIED };
 	struct color bg = { COLOR_UNSPECIFIED };
 
-	if (!strncasecmp(value, "reset", len)) {
+	while (len > 0 && isspace(*ptr)) {
+		ptr++;
+		len--;
+	}
+
+	if (!len) {
+		dst[0] = '\0';
+		return 0;
+	}
+
+	if (!strncasecmp(ptr, "reset", len)) {
 		xsnprintf(dst, end - dst, GIT_COLOR_RESET);
 		return 0;
 	}

graph.c

@@ -3,6 +3,7 @@
 #include "color.h"
 #include "graph.h"
 #include "revision.h"
+#include "argv-array.h"
 
 /* Internal API */
 
@@ -79,6 +80,26 @@ static void graph_show_line_prefix(const struct diff_options *diffopt)
 static const char **column_colors;
 static unsigned short column_colors_max;
 
+static void parse_graph_colors_config(struct argv_array *colors, const char *string)
+{
+	const char *end, *start;
+
+	start = string;
+	end = string + strlen(string);
+	while (start < end) {
+		const char *comma = strchrnul(start, ',');
+		char color[COLOR_MAXLEN];
+
+		if (!color_parse_mem(start, comma - start, color))
+			argv_array_push(colors, color);
+		else
+			warning(_("ignore invalid color '%.*s' in log.graphColors"),
+				(int)(comma - start), start);
+		start = comma + 1;
+	}
+	argv_array_push(colors, GIT_COLOR_RESET);
+}
+
 void graph_set_column_colors(const char **colors, unsigned short colors_max)
 {
 	column_colors = colors;
@@ -238,9 +259,22 @@ struct git_graph *graph_init(struct rev_info *opt)
 {
 	struct git_graph *graph = xmalloc(sizeof(struct git_graph));
 
-	if (!column_colors)
+	if (!column_colors) {
+		char *string;
+		if (git_config_get_string("log.graphcolors", &string)) {
+			/* not configured -- use default */
 			graph_set_column_colors(column_colors_ansi,
 						column_colors_ansi_max);
+		} else {
+			static struct argv_array custom_colors = ARGV_ARRAY_INIT;
+			argv_array_clear(&custom_colors);
+			parse_graph_colors_config(&custom_colors, string);
+			free(string);
+			/* graph_set_column_colors takes a max-index, not a count */
+			graph_set_column_colors(custom_colors.argv,
+						custom_colors.argc - 1);
+		}
+	}
 
 	graph->commit = NULL;
 	graph->revs = opt;

t/t3701-add-interactive.sh

@@ -380,4 +380,18 @@ test_expect_success 'patch mode ignores unmerged entries' '
 	test_cmp expected diff
 '
 
+test_expect_success 'diffs can be colorized' '
+	git reset --hard &&
+
+	# force color even though the test script has no terminal
+	test_config color.ui always &&
+
+	echo content >test &&
+	printf y | git add -p >output 2>&1 &&
+
+	# We do not want to depend on the exact coloring scheme
+	# git uses for diffs, so just check that we saw some kind of color.
+	grep "$(printf "\\033")" output
+'
+
 test_done

t/t4026-color.sh

@@ -6,10 +6,11 @@
 test_description='Test diff/status color escape codes'
 . ./test-lib.sh
 
+ESC=$(printf '\033')
 color()
 {
 	actual=$(git config --get-color no.such.slot "$1") &&
-	test "$actual" = "$2"
+	test "$actual" = "${2:+$ESC}$2"
 }
 
 invalid_color()
@@ -21,6 +22,10 @@ test_expect_success 'reset' '
 	color "reset" "[m"
 '
 
+test_expect_success 'empty color is empty' '
+	color "" ""
+'
+
 test_expect_success 'attribute before color name' '
 	color "bold red" "[1;31m"
 '

t/t4202-log.sh

@@ -359,6 +359,28 @@ test_expect_success 'log --graph --line-prefix="| | | " with merge' '
 	test_cmp expect actual
 '
 
+cat > expect.colors <<\EOF
+*   Merge branch 'side'
+<BLUE>|<RESET><CYAN>\<RESET>
+<BLUE>|<RESET> * side-2
+<BLUE>|<RESET> * side-1
+* <CYAN>|<RESET> Second
+* <CYAN>|<RESET> sixth
+* <CYAN>|<RESET> fifth
+* <CYAN>|<RESET> fourth
+<CYAN>|<RESET><CYAN>/<RESET>
+* third
+* second
+* initial
+EOF
+
+test_expect_success 'log --graph with merge with log.graphColors' '
+	test_config log.graphColors " blue,invalid-color, cyan, red  , " &&
+	git log --color=always --graph --date-order --pretty=tformat:%s |
+		test_decode_color | sed "s/ *\$//" >actual &&
+	test_cmp expect.colors actual
+'
+
 test_expect_success 'log --raw --graph -m with merge' '
 	git log --raw --graph --oneline -m master | head -n 500 >actual &&
 	grep "initial" actual