[PATCH 00/16] nd/setup part two

@@ -535,8 +535,14 @@ char *enter_repo(char *path, int strict)
 
 	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
 	    validate_headref("HEAD") == 0) {
-		set_git_dir(".");
+		inside_work_tree = 0;
+		inside_git_dir = 1;
 		check_repository_format();
+		set_git_dir(".");
+		if (startup_info) {
+			startup_info->prefix = NULL;
+			startup_info->have_repository = 1;
+		}
 		return path;
 	}
 

@@ -350,14 +350,17 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 				/* config may override worktree */
 				if (check_repository_format_gently(nongit_ok))
 					return NULL;
+				set_git_dir(gitdirenv);
 				return retval;
 			}
 			if (check_repository_format_gently(nongit_ok))
 				return NULL;
 			retval = get_relative_cwd(buffer, sizeof(buffer) - 1,
 					get_git_work_tree());
-			if (!retval || !*retval)
+			if (!retval || !*retval) {
+				set_git_dir(gitdirenv);
 				return NULL;
+			}
 			set_git_dir(make_absolute_path(gitdirenv));
 			if (chdir(work_tree_env) < 0)
 				die_errno ("Could not chdir to '%s'", work_tree_env);

@@ -392,8 +395,10 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 	offset = len = strlen(cwd);
 	for (;;) {
 		gitfile_dir = read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT);
-		if (gitfile_dir || is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT)) {
-			if (gitfile_dir && set_git_dir(gitfile_dir))
+		if (!gitfile_dir && is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
+			gitfile_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
+		if (gitfile_dir) {
+			if (set_git_dir(gitfile_dir))
 				die("Repository setup failed");
 			inside_git_dir = 0;
 			if (!work_tree_env)

@@ -646,6 +646,14 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				static char cwd[PATH_MAX];
 				int len;
 				if (gitdir) {
+					if (prefix && !is_absolute_path(gitdir)) {
+						int len;
+						if (!getcwd(cwd, PATH_MAX))
+							die_errno("unable to get current working directory");
+						len = strlen(cwd);
+						printf("%s%s%s\n", cwd, len && cwd[len-1] != '/' ? "/" : "", gitdir);
+						continue;
+					}
 					puts(gitdir);
 					continue;
 				}

@@ -933,6 +933,7 @@ typedef int (*config_fn_t)(const char *, const char *, void *);
 extern int git_default_config(const char *, const char *, void *);
 extern int git_config_from_file(config_fn_t fn, const char *, void *);
 extern int git_config(config_fn_t fn, void *);
+extern int git_config_early(config_fn_t fn, void *, const char *repo_config);
 extern int git_parse_ulong(const char *, unsigned long *);
 extern int git_config_int(const char *, const char *);
 extern unsigned long git_config_ulong(const char *, const char *);

@@ -699,10 +699,9 @@ int git_config_global(void)
 	return !git_env_bool("GIT_CONFIG_NOGLOBAL", 0);
 }
 
-int git_config(config_fn_t fn, void *data)
+int git_config_early(config_fn_t fn, void *data, const char *repo_config)
 {
 	int ret = 0, found = 0;
-	char *repo_config = NULL;
 	const char *home = NULL;
 
 	/* Setting $GIT_CONFIG makes git read _only_ the given config file. */

@@ -724,17 +723,27 @@ int git_config(config_fn_t fn, void *data)
 		free(user_config);
 	}
 
-	repo_config = git_pathdup("config");
-	if (!access(repo_config, R_OK)) {
+	if (repo_config && !access(repo_config, R_OK)) {
 		ret += git_config_from_file(fn, repo_config, data);
 		found += 1;
 	}
-	free(repo_config);
 	if (found == 0)
 		return -1;
 	return ret;
 }
 
+int git_config(config_fn_t fn, void *data)
+{
+	char *repo_config = NULL;
+	int ret;
+
+	repo_config = git_pathdup("config");
+	ret = git_config_early(fn, data, repo_config);
+	if (repo_config)
+		free(repo_config);
+	return ret;
+}
+
 /*
  * Find all the stuff for git_config_set() below.
  */

@@ -241,9 +241,21 @@ void setup_work_tree(void)
 	initialized = 1;
 }
 
-static int check_repository_format_gently(int *nongit_ok)
+static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 {
-	git_config(check_repository_format_version, NULL);
+	char repo_config[PATH_MAX+1];
+
+	/*
+	 * git_config() can't be used here because it calls git_pathdup()
+	 * to get $GIT_CONFIG/config. That call will make setup_git_env()
+	 * set git_dir to ".git".
+	 *
+	 * We are in gitdir setup, no git dir has been found useable yet.
+	 * Use a gentler version of git_config() to check if this repo
+	 * is a good one.
+	 */
+	snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
+	git_config_early(check_repository_format_version, NULL, repo_config);
 	if (GIT_REPO_VERSION < repository_format_version) {
 		if (!nongit_ok)
 			die ("Expected git repo version <= %d, found %d",

@@ -348,12 +360,12 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 			if (!work_tree_env) {
 				retval = set_work_tree(gitdirenv);
 				/* config may override worktree */
-				if (check_repository_format_gently(nongit_ok))
+				if (check_repository_format_gently(gitdirenv, nongit_ok))
 					return NULL;
 				set_git_dir(gitdirenv);
 				return retval;
 			}
-			if (check_repository_format_gently(nongit_ok))
+			if (check_repository_format_gently(gitdirenv, nongit_ok))
 				return NULL;
 			retval = get_relative_cwd(buffer, sizeof(buffer) - 1,
 					get_git_work_tree());

@@ -403,6 +415,8 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 			inside_git_dir = 0;
 			if (!work_tree_env)
 				inside_work_tree = 1;
+			if (check_repository_format_gently(gitfile_dir, nongit_ok))
+				return NULL;
 			root_len = offset_1st_component(cwd);
 			git_work_tree_cfg = xstrndup(cwd, offset > root_len ? offset : root_len);
 			break;

@@ -411,6 +425,8 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 			inside_git_dir = 1;
 			if (!work_tree_env)
 				inside_work_tree = 0;
+			if (check_repository_format_gently(gitfile_dir, nongit_ok))
+				return NULL;
 			if (offset != len) {
 				root_len = offset_1st_component(cwd);
 				cwd[offset > root_len ? offset : root_len] = '\0';

@@ -433,8 +449,6 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 			die_errno("Cannot change to '%s/..'", cwd);
 	}
 
-	if (check_repository_format_gently(nongit_ok))
-		return NULL;
 	if (offset == len)
 		return NULL;
 

@@ -542,7 +556,7 @@ char *enter_repo(char *path, int strict)
 	    validate_headref("HEAD") == 0) {
 		inside_work_tree = 0;
 		inside_git_dir = 1;
-		check_repository_format();
+		check_repository_format_gently(".", NULL);
 		set_git_dir(".");
 		if (startup_info) {
 			startup_info->prefix = NULL;

@@ -627,7 +641,7 @@ int check_repository_format_version(const char *var, const char *value, void *cb
 
 int check_repository_format(void)
 {
-	return check_repository_format_gently(NULL);
+	return check_repository_format_gently(get_git_dir(), NULL);
 }
 
 const char *setup_git_directory(void)

@@ -332,97 +332,6 @@ return_null:
 	return NULL;
 }
 
-/*
- * First, one directory to try is determined by the following algorithm.
- *
- * (0) If "strict" is given, the path is used as given and no DWIM is
- *     done. Otherwise:
- * (1) "~/path" to mean path under the running user's home directory;
- * (2) "~user/path" to mean path under named user's home directory;
- * (3) "relative/path" to mean cwd relative directory; or
- * (4) "/absolute/path" to mean absolute directory.
- *
- * Unless "strict" is given, we try access() for existence of "%s.git/.git",
- * "%s/.git", "%s.git", "%s" in this order.  The first one that exists is
- * what we try.
- *
- * Second, we try chdir() to that.  Upon failure, we return NULL.
- *
- * Then, we try if the current directory is a valid git repository.
- * Upon failure, we return NULL.
- *
- * If all goes well, we return the directory we used to chdir() (but
- * before ~user is expanded), avoiding getcwd() resolving symbolic
- * links.  User relative paths are also returned as they are given,
- * except DWIM suffixing.
- */
-char *enter_repo(char *path, int strict)
-{
-	static char used_path[PATH_MAX];
-	static char validated_path[PATH_MAX];
-
-	if (!path)
-		return NULL;
-
-	if (!strict) {
-		static const char *suffix[] = {
-			".git/.git", "/.git", ".git", "", NULL,
-		};
-		int len = strlen(path);
-		int i;
-		while ((1 < len) && (path[len-1] == '/')) {
-			path[len-1] = 0;
-			len--;
-		}
-		if (PATH_MAX <= len)
-			return NULL;
-		if (path[0] == '~') {
-			char *newpath = expand_user_path(path);
-			if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
-				free(newpath);
-				return NULL;
-			}
-			/*
-			 * Copy back into the static buffer. A pity
-			 * since newpath was not bounded, but other
-			 * branches of the if are limited by PATH_MAX
-			 * anyway.
-			 */
-			strcpy(used_path, newpath); free(newpath);
-			strcpy(validated_path, path);
-			path = used_path;
-		}
-		else if (PATH_MAX - 10 < len)
-			return NULL;
-		else {
-			path = strcpy(used_path, path);
-			strcpy(validated_path, path);
-		}
-		len = strlen(path);
-		for (i = 0; suffix[i]; i++) {
-			strcpy(path + len, suffix[i]);
-			if (!access(path, F_OK)) {
-				strcat(validated_path, suffix[i]);
-				break;
-			}
-		}
-		if (!suffix[i] || chdir(path))
-			return NULL;
-		path = validated_path;
-	}
-	else if (chdir(path))
-		return NULL;
-
-	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
-	    validate_headref("HEAD") == 0) {
-		set_git_dir(".");
-		check_repository_format();
-		return path;
-	}
-
-	return NULL;
-}
-
 int set_shared_perm(const char *path, int mode)
 {
 	struct stat st;

@@ -452,6 +452,97 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	return prefix;
 }
 
+/*
+ * First, one directory to try is determined by the following algorithm.
+ *
+ * (0) If "strict" is given, the path is used as given and no DWIM is
+ *     done. Otherwise:
+ * (1) "~/path" to mean path under the running user's home directory;
+ * (2) "~user/path" to mean path under named user's home directory;
+ * (3) "relative/path" to mean cwd relative directory; or
+ * (4) "/absolute/path" to mean absolute directory.
+ *
+ * Unless "strict" is given, we try access() for existence of "%s.git/.git",
+ * "%s/.git", "%s.git", "%s" in this order.  The first one that exists is
+ * what we try.
+ *
+ * Second, we try chdir() to that.  Upon failure, we return NULL.
+ *
+ * Then, we try if the current directory is a valid git repository.
+ * Upon failure, we return NULL.
+ *
+ * If all goes well, we return the directory we used to chdir() (but
+ * before ~user is expanded), avoiding getcwd() resolving symbolic
+ * links.  User relative paths are also returned as they are given,
+ * except DWIM suffixing.
+ */
+char *enter_repo(char *path, int strict)
+{
+	static char used_path[PATH_MAX];
+	static char validated_path[PATH_MAX];
+
+	if (!path)
+		return NULL;
+
+	if (!strict) {
+		static const char *suffix[] = {
+			".git/.git", "/.git", ".git", "", NULL,
+		};
+		int len = strlen(path);
+		int i;
+		while ((1 < len) && (path[len-1] == '/')) {
+			path[len-1] = 0;
+			len--;
+		}
+		if (PATH_MAX <= len)
+			return NULL;
+		if (path[0] == '~') {
+			char *newpath = expand_user_path(path);
+			if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
+				free(newpath);
+				return NULL;
+			}
+			/*
+			 * Copy back into the static buffer. A pity
+			 * since newpath was not bounded, but other
+			 * branches of the if are limited by PATH_MAX
+			 * anyway.
+			 */
+			strcpy(used_path, newpath); free(newpath);
+			strcpy(validated_path, path);
+			path = used_path;
+		}
+		else if (PATH_MAX - 10 < len)
+			return NULL;
+		else {
+			path = strcpy(used_path, path);
+			strcpy(validated_path, path);
+		}
+		len = strlen(path);
+		for (i = 0; suffix[i]; i++) {
+			strcpy(path + len, suffix[i]);
+			if (!access(path, F_OK)) {
+				strcat(validated_path, suffix[i]);
+				break;
+			}
+		}
+		if (!suffix[i] || chdir(path))
+			return NULL;
+		path = validated_path;
+	}
+	else if (chdir(path))
+		return NULL;
+
+	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
+	    validate_headref("HEAD") == 0) {
+		set_git_dir(".");
+		check_repository_format();
+		return path;
+	}
+
+	return NULL;
+}
+
 int git_config_perm(const char *var, const char *value)
 {
 	int i;

@@ -418,6 +418,7 @@ extern const char **get_pathspec(const char *prefix, const char **pathspec);
 extern void setup_work_tree(void);
 extern const char *setup_git_directory_gently(int *);
 extern const char *setup_git_directory(void);
+extern void unset_git_directory(const char *prefix);
 extern const char *prefix_path(const char *prefix, int len, const char *path);
 extern const char *prefix_filename(const char *prefix, int len, const char *path);
 extern int check_filename(const char *prefix, const char *name);

@@ -323,6 +323,26 @@ const char *read_gitfile_gently(const char *path)
 	return path;
 }
 
+void unset_git_directory(const char *prefix)
+{
+	if (prefix && chdir(prefix))
+		die("Cannot change to '%s'", prefix);
+
+	if (startup_info) {
+		startup_info->prefix = NULL;
+		startup_info->have_repository = 0;
+	}
+
+	/* Initialized in setup_git_directory_gently_1() */
+	inside_work_tree = -1;
+	inside_git_dir = -1;
+
+	/* Initialized in check_repository_format_version() */
+	repository_format_version = 0xFF;
+	shared_repository = PERM_UMASK;
+	is_bare_repository_cfg = -1;
+	git_work_tree_cfg = NULL;
+}
 /*
  * We cannot decide in this function whether we are in the work tree or
  * not, since the config can only be read _after_ this function was called.

@@ -403,6 +423,13 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 	 * - ../ (bare)
 	 * - ../../.git/
 	 *   etc.
+	 *
+	 * When a repository is found:
+	 * - inside_git_dir/inside_work_tree are set
+	 * - check_repository_format_gently() is called
+	 *   if repo version is not supported, restore cwd
+	 * - set_git_dir
+	 * - calculate and return prefix
 	 */
 	offset = len = strlen(cwd);
 	for (;;) {

@@ -410,13 +437,15 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 		if (!gitfile_dir && is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 			gitfile_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
 		if (gitfile_dir) {
-			if (set_git_dir(gitfile_dir))
-				die("Repository setup failed");
 			inside_git_dir = 0;
 			if (!work_tree_env)
 				inside_work_tree = 1;
-			if (check_repository_format_gently(gitfile_dir, nongit_ok))
+			if (check_repository_format_gently(gitfile_dir, nongit_ok)) {
+				unset_git_directory(offset != len ? cwd + offset + 1: NULL);
 				return NULL;
+			}
+			if (set_git_dir(gitfile_dir))
+				die("Repository setup failed");
 			root_len = offset_1st_component(cwd);
 			git_work_tree_cfg = xstrndup(cwd, offset > root_len ? offset : root_len);
 			break;

@@ -425,8 +454,10 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
 			inside_git_dir = 1;
 			if (!work_tree_env)
 				inside_work_tree = 0;
-			if (check_repository_format_gently(gitfile_dir, nongit_ok))
+			if (check_repository_format_gently(gitfile_dir, nongit_ok)) {
+				unset_git_directory(offset != len ? cwd + offset + 1: NULL);
 				return NULL;
+			}
 			if (offset != len) {
 				root_len = offset_1st_component(cwd);
 				cwd[offset > root_len ? offset : root_len] = '\0';

@@ -737,7 +737,8 @@ int git_config(config_fn_t fn, void *data)
 	char *repo_config = NULL;
 	int ret;
 
-	repo_config = git_pathdup("config");
+	if (!startup_info || startup_info->have_repository)
+		repo_config = git_pathdup("config");
 	ret = git_config_early(fn, data, repo_config);
 	if (repo_config)
 		free(repo_config);

@@ -824,4 +824,17 @@ test_expect_success 'check split_cmdline return' "
 	test_must_fail git merge master
 	"
 
+test_expect_success 'skip .git/config if there is no repository' '
+	(
+		mkdir -p a/b/.git &&
+		cd a &&
+		GIT_CEILING_DIRECTORIES="`pwd`" &&
+		export GIT_CEILING_DIRECTORIES &&
+		cd b &&
+		echo "[core]" > .git/config &&
+		echo "wrong = true" >> .git/config &&
+		test -z "$(git var -l | grep core.wrong)"
+	)
+'
+
 test_done

@@ -460,9 +460,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 
 	if (safe_create_leading_directories_const(git_dir) < 0)
 		die("could not create leading directories of '%s'", git_dir);
-	set_git_dir(make_absolute_path(git_dir));
 
-	init_db(option_template, option_quiet ? INIT_DB_QUIET : 0);
+	init_db(git_dir, option_template, option_quiet ? INIT_DB_QUIET : 0);
 
 	/*
 	 * At this point, the config exists, so we do not need the

@@ -294,12 +294,15 @@ static int create_default_files(const char *template_path)
 	return reinit;
 }
 
-int init_db(const char *template_dir, unsigned int flags)
+int init_db(const char *git_dir, const char *template_dir, unsigned int flags)
 {
 	const char *sha1_dir;
 	char *path;
 	int len, reinit;
 
+	set_git_dir(make_absolute_path(git_dir));
+	startup_info->have_repository = 1;
+
 	safe_create_dir(get_git_dir(), 0);
 
 	init_is_bare_repository = is_bare_repository();

@@ -509,7 +512,5 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 				   get_git_work_tree());
 	}
 
-	set_git_dir(make_absolute_path(git_dir));
-
-	return init_db(template_dir, flags);
+	return init_db(git_dir, template_dir, flags);
 }

@@ -427,7 +427,7 @@ extern void verify_non_filename(const char *prefix, const char *name);
 
 #define INIT_DB_QUIET 0x0001
 
-extern int init_db(const char *template_dir, unsigned int flags);
+extern int init_db(const char *git_dir, const char *template_dir, unsigned int flags);
 
 #define alloc_nr(x) (((x)+16)*3/2)
 

@@ -1024,9 +1024,11 @@ void setup_standard_excludes(struct dir_struct *dir)
 	const char *path;
 
 	dir->exclude_per_dir = ".gitignore";
-	path = git_path("info/exclude");
-	if (!access(path, R_OK))
-		add_excludes_from_file(dir, path);
+	if (!startup_info || startup_info->have_repository) {
+		path = git_path("info/exclude");
+		if (!access(path, R_OK))
+			add_excludes_from_file(dir, path);
+	}
 	if (excludes_file && !access(excludes_file, R_OK))
 		add_excludes_from_file(dir, excludes_file);
 }

@@ -527,4 +527,28 @@ test_expect_success 'grep -e -- -- path' '
 	test_cmp expected actual
 '
 
+test_expect_success 'Setup fake .git' '
+	cd t &&
+	GIT_CEILING_DIRECTORIES="`pwd`" &&
+	export GIT_CEILING_DIRECTORIES &&
+	cd a &&
+	mkdir -p .git/info &&
+	cd ../..
+
+'
+
+test_expect_success 'Ignore fake .git/info/exclude' '
+	(
+		cd t/a &&
+		echo v > .git/info/exclude &&
+		git grep --no-index vvv . &&
+		rm .git/info/exclude
+	)
+'
+
+test_expect_success 'Unsetup fake .git' '
+	rm -rf t/a &&
+	unset GIT_CEILING_DIRECTORIES
+'
+
 test_done

@@ -480,7 +480,10 @@ static void bootstrap_attr_stack(void)
 			debug_push(elem);
 		}
 
-		elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
+		if (!startup_info || startup_info->have_repository)
+			elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
+		else
+			elem = NULL;
 		if (!elem)
 			elem = xcalloc(1, sizeof(*elem));
 		elem->origin = NULL;

@@ -2441,7 +2441,7 @@ static int apply_binary(struct image *img, struct patch *patch)
 		return 0; /* deletion patch */
 	}
 
-	if (has_sha1_file(sha1)) {
+	if (startup_info->have_repository && has_sha1_file(sha1)) {
 		/* We already have the postimage */
 		enum object_type type;
 		unsigned long size;

@@ -159,7 +159,8 @@ static int get_value(const char *key_, const char *regex_)
 	local = config_exclusive_filename;
 	if (!local) {
 		const char *home = getenv("HOME");
-		local = repo_config = git_pathdup("config");
+		if (startup_info->have_repository)
+			local = repo_config = git_pathdup("config");
 		if (git_config_global() && home)
 			global = xstrdup(mkpath("%s/.gitconfig", home));
 		if (git_config_system())

@@ -197,7 +198,8 @@ static int get_value(const char *key_, const char *regex_)
 		git_config_from_file(show_config, system_wide, NULL);
 	if (do_all && global)
 		git_config_from_file(show_config, global, NULL);
-	git_config_from_file(show_config, local, NULL);
+	if (local)
+		git_config_from_file(show_config, local, NULL);
 	if (!do_all && !seen && global)
 		git_config_from_file(show_config, global, NULL);
 	if (!do_all && !seen && system_wide)

@@ -215,7 +217,8 @@ static int get_value(const char *key_, const char *regex_)
 		ret = (seen == 1) ? 0 : seen > 1 ? 2 : 1;
 
 free_strings:
-	free(repo_config);
+	if (repo_config)
+		free(repo_config);
 	free(global);
 	return ret;
 }

@@ -833,7 +833,8 @@ test_expect_success 'skip .git/config if there is no repository' '
 		cd b &&
 		echo "[core]" > .git/config &&
 		echo "wrong = true" >> .git/config &&
-		test -z "$(git var -l | grep core.wrong)"
+		test -z "$(git var -l | grep core.wrong)" &&
+		test -z "$(git config --bool core.wrong)"
 	)
 '
 

@@ -29,7 +29,7 @@ test_expect_success 'gitdir selection on normal repos' '
 # Make sure it would stop at test2, not trash
 test_expect_success 'gitdir selection on unsupported repo' '
 	(cd test2 &&
-	test "$(git config core.repositoryformatversion)" = 99)'
+	test "$(git config --file=.git/config core.repositoryformatversion)" = 99)'
 
 test_expect_success 'gitdir not required mode' '
 	(git apply --stat test.patch &&

@@ -419,6 +419,7 @@ extern void setup_work_tree(void);
 extern const char *setup_git_directory_gently(int *);
 extern const char *setup_git_directory(void);
 extern void unset_git_directory(const char *prefix);
+extern void unset_git_env();
 extern const char *prefix_path(const char *prefix, int len, const char *path);
 extern const char *prefix_filename(const char *prefix, int len, const char *path);
 extern int check_filename(const char *prefix, const char *name);

@@ -62,6 +62,7 @@ char *git_work_tree_cfg;
 static char *work_tree;
 
 static const char *git_dir;
+static const char *original_git_dir;
 static char *git_object_dir, *git_index_file, *git_refs_dir, *git_graft_file;
 
 /*

@@ -81,6 +82,20 @@ const char * const local_repo_env[LOCAL_REPO_ENV_SIZE + 1] = {
 	NULL
 };
 
+void unset_git_env(void)
+{
+	git_dir = NULL;
+	if (original_git_dir)
+		setenv(GIT_DIR_ENVIRONMENT, original_git_dir, 1);
+	else
+		unsetenv(GIT_DIR_ENVIRONMENT);
+	git_object_dir = NULL;
+	git_refs_dir = NULL;
+	git_index_file = NULL;
+	git_graft_file = NULL;
+	read_replace_refs = 1;
+}
+
 static void setup_git_env(void)
 {
 	git_dir = getenv(GIT_DIR_ENVIRONMENT);

@@ -184,6 +199,11 @@ char *get_graft_file(void)
 
 int set_git_dir(const char *path)
 {
+	static int original_git_dir_set = 0;
+	if (!original_git_dir_set) {
+		original_git_dir = getenv(GIT_DIR_ENVIRONMENT);
+		original_git_dir_set = 1;
+	}
 	if (setenv(GIT_DIR_ENVIRONMENT, path, 1))
 		return error("Could not set GIT_DIR to '%s'", path);
 	setup_git_env();

@@ -146,14 +146,13 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 static int handle_alias(int *argcp, const char ***argv)
 {
 	int envchanged = 0, ret = 0, saved_errno = errno;
-	const char *subdir;
 	int count, option_count;
 	const char **new_argv;
 	const char *alias_command;
 	char *alias_string;
 	int unused_nongit;
 
-	subdir = setup_git_directory_gently(&unused_nongit);
+	setup_git_directory_gently(&unused_nongit);
 
 	alias_command = (*argv)[0];
 	alias_string = alias_lookup(alias_command);

@@ -210,8 +209,7 @@ static int handle_alias(int *argcp, const char ***argv)
 		ret = 1;
 	}
 
-	if (subdir && chdir(subdir))
-		die_errno("Cannot change to '%s'", subdir);
+	unset_git_directory(startup_info->prefix);
 
 	errno = saved_errno;
 

@@ -240,8 +238,6 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 	int status, help;
 	struct stat st;
 
-	memset(&git_startup_info, 0, sizeof(git_startup_info));
-	startup_info = &git_startup_info;
 	help = argc == 2 && !strcmp(argv[1], "-h");
 	if (!help) {
 		if (p->option & RUN_SETUP)

@@ -486,6 +482,9 @@ int main(int argc, const char **argv)
 {
 	const char *cmd;
 
+	memset(&git_startup_info, 0, sizeof(git_startup_info));
+	startup_info = &git_startup_info;
+
 	cmd = git_extract_argv0_path(argv[0]);
 	if (!cmd)
 		cmd = "git-help";

@@ -329,6 +329,8 @@ void unset_git_directory(const char *prefix)
 		die("Cannot change to '%s'", prefix);
 
 	if (startup_info) {
+		if (startup_info->have_repository)
+			unset_git_env();
 		startup_info->prefix = NULL;
 		startup_info->have_repository = 0;
 	}

@@ -152,7 +152,8 @@ static int handle_alias(int *argcp, const char ***argv)
 	char *alias_string;
 	int unused_nongit;
 
-	setup_git_directory_gently(&unused_nongit);
+	if (!startup_info->have_repository)
+		setup_git_directory_gently(&unused_nongit);
 
 	alias_command = (*argv)[0];
 	alias_string = alias_lookup(alias_command);

@@ -209,8 +210,6 @@ static int handle_alias(int *argcp, const char ***argv)
 		ret = 1;
 	}
 
-	unset_git_directory(startup_info->prefix);
-
 	errno = saved_errno;
 
 	return ret;

@@ -240,12 +239,18 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 
 	help = argc == 2 && !strcmp(argv[1], "-h");
 	if (!help) {
-		if (p->option & RUN_SETUP)
+		if ((p->option & RUN_SETUP) && !startup_info->have_repository)
 			setup_git_directory();
-		if (p->option & RUN_SETUP_GENTLY) {
+		else if ((p->option & RUN_SETUP_GENTLY) && !startup_info->have_repository) {
 			int nongit_ok;
 			setup_git_directory_gently(&nongit_ok);
 		}
+		else if (startup_info->have_repository) {
+			if (p->option & (RUN_SETUP_GENTLY | RUN_SETUP))
+				; /* done already */
+			else
+				unset_git_directory(startup_info->prefix);
+		}
 
 		if (use_pager == -1 && p->option & RUN_SETUP)
 			use_pager = check_pager_config(p->cmd);

@@ -302,6 +302,7 @@ int init_db(const char *git_dir, const char *template_dir, unsigned int flags)
 
 	set_git_dir(make_absolute_path(git_dir));
 	startup_info->have_repository = 1;
+	startup_info->have_run_setup_gitdir = 1;
 
 	safe_create_dir(get_git_dir(), 0);
 

@@ -1060,6 +1060,7 @@ int split_cmdline(char *cmdline, const char ***argv);
 /* git.c */
 struct startup_info {
 	const char *prefix;
+	int have_run_setup_gitdir;
 	int have_repository;
 };
 extern struct startup_info *startup_info;