RFC patchinit-db: introduce new -c/--config option

Documentation/git-init.txt, builtin/init-db.c, t/t0001-init.sh

diff --git a/Documentation/git-init.txt b/Documentation/git-init.txt
index 8174d27..3ecbf2a 100644
--- a/Documentation/git-init.txt
+++ b/Documentation/git-init.txt
@@ -10,7 +10,7 @@ SYNOPSIS
 --------
 [verse]
 'git init' [-q | --quiet] [--bare] [--template=<template_directory>]
-	  [--separate-git-dir <git dir>]
+	  [--separate-git-dir <git dir>] [--config <key>=<value>]
 	  [--shared[=<permissions>]] [directory]
 
 
@@ -111,6 +111,15 @@ into it.
 If you provide a 'directory', the command is run inside it. If this directory
 does not exist, it will be created.
 
+--config <key>=<value>::
+-c <key>=<value>::
+Set a new configuration option in the new repository. The <key> expected in
+the same format as linkgit:git-config[1] (e.g., `core.eol=true`). If
+This option can be used multiply times. If multiply options are given with
+the same keys, each value will be written to the config. If given key is
+the same that used in the default configuration file, previous value
+will be overwritten.
+
 --
 
 TEMPLATE DIRECTORY
diff --git a/builtin/init-db.c b/builtin/init-db.c
index 280454a..184de40 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -471,6 +471,26 @@ static const char *const init_db_usage[] = {
 	NULL
 };
 
+static int write_one_config(const char *key, const char *value, void *data) {
+	char *v = NULL;
+	git_config_get_string(key, &v);
+	if (v) {
+		git_config_set(key, value);
+		return 1
+	} else
+		return git_config_set_multivar(key, value ? value : "true", "^$", 0);
+}
+
+static void write_config(struct string_list *config){
+	int i;
+
+	for (i = 0; i < config->nr; i++) {
+		if (git_config_parse_parameter(config->items[i].string,
+					       write_one_config, NULL) < 0)
+			die("unable to write parameters to config file");
+	}
+}
+
 /*
  * If you want to, you can share the DB area with any number of branches.
  * That has advantages: you can save space by sharing all the SHA1 objects.
@@ -479,11 +499,13 @@ static const char *const init_db_usage[] = {
  */
 int cmd_init_db(int argc, const char **argv, const char *prefix)
 {
+	int ret;
 	const char *git_dir;
 	const char *real_git_dir = NULL;
 	const char *work_tree;
 	const char *template_dir = NULL;
 	unsigned int flags = 0;
+	static struct string_list option_config;
 	const struct option init_db_options[] = {
 		OPT_STRING(0, "template", &template_dir, N_("template-directory"),
 				N_("directory from which templates will be used")),
@@ -496,6 +518,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 		OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
 		OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
 			   N_("separate git dir from working tree")),
+		OPT_STRING_LIST('c', "config", &option_config, N_("key=value"),
+			   N_("set config inside the new repository")),
 		OPT_END()
 	};
 
@@ -592,6 +616,11 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 	}
 
 	set_git_dir_init(git_dir, real_git_dir, 1);
-
-	return init_db(template_dir, flags);
+	ret = init_db(template_dir, flags);
+	/*
+	 * new repository already created, so we can update .git/config if
+	 * -c/--config passed
+	 */
+	write_config(&option_config);
+	return ret;
 }
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 7de8d85..8ce3537 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -339,4 +339,20 @@ test_expect_success SYMLINKS 're-init to move gitdir symlink' '
 	test_path_is_dir realgitdir/refs
 '
 
+test_expect_success 'git init -c key=value' '
+	rm -rf newdir realgitdir &&
+	git init -c core.foo=bar newdir &&
+	echo bar >expect &&
+	git --git-dir=newdir/.git config core.foo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git init -c key=value override default value' '
+	rm -rf newdir &&
+	git init -c core.filemode=false newdir &&
+	echo false >expect &&
+	git --git-dir=newdir/.git config core.filemode >actual &&
+	test_cmp expect actual
+'
+
 test_done