Merge branch 'tb/config-default'

"git config --get" learned the "--default" option, to help the
calling script.  Building on top of the tb/config-type topic, the
"git config" learns "--type=color" type.  Taken together, you can
do things like "git config --get foo.color --default blue" and get
the ANSI color sequence for the color given to foo.color variable,
or "blue" if the variable does not exist.

* tb/config-default:
  builtin/config: introduce `color` type specifier
  config.c: introduce 'git_config_color' to parse ANSI colors
  builtin/config: introduce `--default`

1 files changed, 40 insertions, 0 deletions

diff --git a/builtin/config.c b/builtin/config.c
index 24d735e..69e7270 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -26,6 +26,7 @@ static char term = '\n';
 static int use_global_config, use_system_config, use_local_config;
 static struct git_config_source given_config_source;
 static int actions, type;
+static char *default_value;
 static int end_null;
 static int respect_includes_opt = -1;
 static struct config_options config_options;
@@ -60,6 +61,7 @@ static int show_origin;
 #define TYPE_BOOL_OR_INT	3
 #define TYPE_PATH		4
 #define TYPE_EXPIRY_DATE	5
+#define TYPE_COLOR		6
 
 #define OPT_CALLBACK_VALUE(s, l, v, h, i) \
 	{ OPTION_CALLBACK, (s), (l), (v), NULL, (h), PARSE_OPT_NOARG | \
@@ -93,6 +95,8 @@ static int option_parse_type(const struct option *opt, const char *arg,
 			new_type = TYPE_PATH;
 		else if (!strcmp(arg, "expiry-date"))
 			new_type = TYPE_EXPIRY_DATE;
+		else if (!strcmp(arg, "color"))
+			new_type = TYPE_COLOR;
 		else
 			die(_("unrecognized --type argument, %s"), arg);
 	}
@@ -149,6 +153,7 @@ static struct option builtin_config_options[] = {
 	OPT_BOOL(0, "name-only", &omit_values, N_("show variable names only")),
 	OPT_BOOL(0, "includes", &respect_includes_opt, N_("respect include directives on lookup")),
 	OPT_BOOL(0, "show-origin", &show_origin, N_("show origin of config (file, standard input, blob, command line)")),
+	OPT_STRING(0, "default", &default_value, N_("value"), N_("with --get, use default value when missing entry")),
 	OPT_END(),
 };
 
@@ -228,6 +233,11 @@ static int format_config(struct strbuf *buf, const char *key_, const char *value
 			if (git_config_expiry_date(&t, key_, value_) < 0)
 				return -1;
 			strbuf_addf(buf, "%"PRItime, t);
+		} else if (type == TYPE_COLOR) {
+			char v[COLOR_MAXLEN];
+			if (git_config_color(v, key_, value_) < 0)
+				return -1;
+			strbuf_addstr(buf, v);
 		} else if (value_) {
 			strbuf_addstr(buf, value_);
 		} else {
@@ -313,6 +323,16 @@ static int get_value(const char *key_, const char *regex_)
 	config_with_options(collect_config, &values,
 			    &given_config_source, &config_options);
 
+	if (!values.nr && default_value) {
+		struct strbuf *item;
+		ALLOC_GROW(values.items, values.nr + 1, values.alloc);
+		item = &values.items[values.nr++];
+		strbuf_init(item, 0);
+		if (format_config(item, key_, default_value) < 0)
+			die(_("failed to format default config value: %s"),
+				default_value);
+	}
+
 	ret = !values.nr;
 
 	for (i = 0; i < values.nr; i++) {
@@ -363,6 +383,20 @@ static char *normalize_value(const char *key, const char *value)
 		else
 			return xstrdup(v ? "true" : "false");
 	}
+	if (type == TYPE_COLOR) {
+		char v[COLOR_MAXLEN];
+		if (git_config_color(v, key, value))
+			die("cannot parse color '%s'", value);
+
+		/*
+		 * The contents of `v` now contain an ANSI escape
+		 * sequence, not suitable for including within a
+		 * configuration file. Treat the above as a
+		 * "sanity-check", and return the given value, which we
+		 * know is representable as valid color code.
+		 */
+		return xstrdup(value);
+	}
 
 	die("BUG: cannot normalize type %d", type);
 }
@@ -651,6 +685,12 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		usage_with_options(builtin_config_usage, builtin_config_options);
 	}
 
+	if (default_value && !(actions & ACTION_GET)) {
+		error("--default is only applicable to --get");
+		usage_with_options(builtin_config_usage,
+			builtin_config_options);
+	}
+
 	if (actions & PAGING_ACTIONS)
 		setup_auto_pager("config", 1);