Merge branch 'ei/worktree+filter'

* ei/worktree+filter:
  filter-branch: always export GIT_DIR if it is set
  setup_git_directory: fix segfault if repository is found in cwd
  test GIT_WORK_TREE
  extend rev-parse test for --is-inside-work-tree
  Use new semantics of is_bare/inside_git_dir/inside_work_tree
  introduce GIT_WORK_TREE to specify the work tree
  test git rev-parse
  rev-parse: introduce --is-bare-repository
  rev-parse: document --is-inside-git-dir

15 files changed, 406 insertions, 82 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index a2057d9d24..3dc17a6d78 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -172,6 +172,13 @@ repository that ends in "/.git" is assumed to be not bare (bare =
 false), while all other repositories are assumed to be bare (bare
 = true).
 
+core.worktree::
+	Set the path to the working tree.  The value will not be
+	used in combination with repositories found automatically in
+	a .git directory (i.e. $GIT_DIR is not set).
+	This can be overriden by the GIT_WORK_TREE environment
+	variable and the '--work-tree' command line option.
+
 core.logAllRefUpdates::
 	Updates to a ref <ref> is logged to the file
 	"$GIT_DIR/logs/<ref>", by appending the new and old
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 87771b832b..eea9c9cfe9 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -90,8 +90,15 @@ OPTIONS
 	Show `$GIT_DIR` if defined else show the path to the .git directory.
 
 --is-inside-git-dir::
-	Return "true" if we are in the git directory, otherwise "false".
-	Some commands require to be run in a working directory.
+	When the current working directory is below the repository
+	directory print "true", otherwise "false".
+
+--is-inside-work-tree::
+	When the current working directory is inside the work tree of the
+	repository print "true", otherwise "false".
+
+--is-bare-repository::
+	When the repository is bare print "true", otherwise "false".
 
 --short, --short=number::
 	Instead of outputting the full SHA1 values of object names try to
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 826914837b..2cc0b214d2 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -10,7 +10,8 @@ SYNOPSIS
 --------
 [verse]
 'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [-p|--paginate]
-    [--bare] [--git-dir=GIT_DIR] [--help] COMMAND [ARGS]
+    [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
+    [--help] COMMAND [ARGS]
 
 DESCRIPTION
 -----------
@@ -103,6 +104,14 @@ OPTIONS
 	Set the path to the repository. This can also be controlled by
 	setting the GIT_DIR environment variable.
 
+--work-tree=<path>::
+	Set the path to the working tree.  The value will not be
+	used in combination with repositories found automatically in
+	a .git directory (i.e. $GIT_DIR is not set).
+	This can also be controlled by setting the GIT_WORK_TREE
+	environment variable and the core.worktree configuration
+	variable.
+
 --bare::
 	Same as --git-dir=`pwd`.
 
@@ -347,6 +356,13 @@ git so take care if using Cogito etc.
 	specifies a path to use instead of the default `.git`
 	for the base of the repository.
 
+'GIT_WORK_TREE'::
+	Set the path to the working tree.  The value will not be
+	used in combination with repositories found automatically in
+	a .git directory (i.e. $GIT_DIR is not set).
+	This can also be controlled by the '--work-tree' command line
+	option and the core.worktree configuration variable.
+
 git Commits
 ~~~~~~~~~~~
 'GIT_AUTHOR_NAME'::
diff --git a/builtin-ls-files.c b/builtin-ls-files.c
index 5398a41415..61577ea13f 100644
--- a/builtin-ls-files.c
+++ b/builtin-ls-files.c
@@ -470,7 +470,7 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 	}
 
 	if (require_work_tree &&
-			(is_bare_repository() || is_inside_git_dir()))
+			(!is_inside_work_tree() || is_inside_git_dir()))
 		die("This operation must be run in a work tree");
 
 	pathspec = get_pathspec(prefix, argv + i);
diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
index 37addb25fa..497903a85a 100644
--- a/builtin-rev-parse.c
+++ b/builtin-rev-parse.c
@@ -352,6 +352,16 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 						: "false");
 				continue;
 			}
+			if (!strcmp(arg, "--is-inside-work-tree")) {
+				printf("%s\n", is_inside_work_tree() ? "true"
+						: "false");
+				continue;
+			}
+			if (!strcmp(arg, "--is-bare-repository")) {
+				printf("%s\n", is_bare_repository() ? "true"
+						: "false");
+				continue;
+			}
 			if (!prefixcmp(arg, "--since=")) {
 				show_datestring("--max-age=", arg+8);
 				continue;
diff --git a/cache.h b/cache.h
index 0525c4ee55..dcadfef929 100644
--- a/cache.h
+++ b/cache.h
@@ -192,6 +192,7 @@ enum object_type {
 };
 
 #define GIT_DIR_ENVIRONMENT "GIT_DIR"
+#define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"
 #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
@@ -207,6 +208,7 @@ enum object_type {
 extern int is_bare_repository_cfg;
 extern int is_bare_repository(void);
 extern int is_inside_git_dir(void);
+extern int is_inside_work_tree(void);
 extern const char *get_git_dir(void);
 extern char *get_object_directory(void);
 extern char *get_refs_directory(void);
diff --git a/connect.c b/connect.c
index a5afd2a536..65e79edc77 100644
--- a/connect.c
+++ b/connect.c
@@ -587,6 +587,7 @@ pid_t git_connect(int fd[2], char *url, const char *prog, int flags)
 			unsetenv(ALTERNATE_DB_ENVIRONMENT);
 			unsetenv(DB_ENVIRONMENT);
 			unsetenv(GIT_DIR_ENVIRONMENT);
+			unsetenv(GIT_WORK_TREE_ENVIRONMENT);
 			unsetenv(GRAFT_ENVIRONMENT);
 			unsetenv(INDEX_ENVIRONMENT);
 			execlp("sh", "sh", "-c", command, NULL);
diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 8fa5ce6467..a2fcebc1c6 100644
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -312,9 +312,10 @@ case "$GIT_DIR" in
 /*)
 	;;
 *)
-	export GIT_DIR="$(pwd)/../../$GIT_DIR"
+	GIT_DIR="$(pwd)/../../$GIT_DIR"
 	;;
 esac
+export GIT_DIR GIT_WORK_TREE=.
 
 export GIT_INDEX_FILE="$(pwd)/../index"
 git-read-tree # seed the index file
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index f24c7f2d23..0de49e8459 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -29,11 +29,7 @@ set_reflog_action() {
 }
 
 is_bare_repository () {
-	git-config --bool --get core.bare ||
-	case "$GIT_DIR" in
-	.git | */.git) echo false ;;
-	*) echo true ;;
-	esac
+	git-rev-parse --is-bare-repository
 }
 
 cd_to_toplevel () {
@@ -48,7 +44,7 @@ cd_to_toplevel () {
 }
 
 require_work_tree () {
-	test $(is_bare_repository) = false &&
+	test $(git-rev-parse --is-inside-work-tree) = true &&
 	test $(git-rev-parse --is-inside-git-dir) = false ||
 	die "fatal: $0 cannot be used without a working tree."
 }
diff --git a/git-svn.perl b/git-svn.perl
index 98687f54d7..03d5e2d979 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -596,8 +596,7 @@ sub post_fetch_checkout {
 	my $index = $ENV{GIT_INDEX_FILE} || "$ENV{GIT_DIR}/index";
 	return if -f $index;
 
-	chomp(my $bare = `git config --bool --get core.bare`);
-	return if $bare eq 'true';
+	return if command_oneline(qw/rev-parse --is-inside-work-tree/) eq 'false';
 	return if command_oneline(qw/rev-parse --is-inside-git-dir/) eq 'true';
 	command_noisy(qw/read-tree -m -u -v HEAD HEAD/);
 	print STDERR "Checked out HEAD:\n  ",
diff --git a/git.c b/git.c
index cfec5d70ee..b6bf5ad5ec 100644
--- a/git.c
+++ b/git.c
@@ -4,7 +4,7 @@
 #include "quote.h"
 
 const char git_usage_string[] =
-	"git [--version] [--exec-path[=GIT_EXEC_PATH]] [-p|--paginate] [--bare] [--git-dir=GIT_DIR] [--help] COMMAND [ARGS]";
+	"git [--version] [--exec-path[=GIT_EXEC_PATH]] [-p|--paginate] [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE] [--help] COMMAND [ARGS]";
 
 static void prepend_to_path(const char *dir, int len)
 {
@@ -69,6 +69,16 @@ static int handle_options(const char*** argv, int* argc)
 			handled++;
 		} else if (!prefixcmp(cmd, "--git-dir=")) {
 			setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1);
+		} else if (!strcmp(cmd, "--work-tree")) {
+			if (*argc < 2) {
+				fprintf(stderr, "No directory given for --work-tree.\n" );
+				usage(git_usage_string);
+			}
+			setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
+			(*argv)++;
+			(*argc)--;
+		} else if (!prefixcmp(cmd, "--work-tree=")) {
+			setenv(GIT_WORK_TREE_ENVIRONMENT, cmd + 12, 1);
 		} else if (!strcmp(cmd, "--bare")) {
 			static char git_dir[PATH_MAX+1];
 			setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 1);
@@ -214,7 +224,7 @@ const char git_version_string[] = GIT_VERSION;
  * require working tree to be present -- anything uses this needs
  * RUN_SETUP for reading from the configuration file.
  */
-#define NOT_BARE 	(1<<2)
+#define NEED_WORK_TREE	(1<<2)
 
 struct cmd_struct {
 	const char *cmd;
@@ -233,10 +243,9 @@ static int run_command(struct cmd_struct *p, int argc, const char **argv)
 		prefix = setup_git_directory();
 	if (p->option & USE_PAGER)
 		setup_pager();
-	if (p->option & NOT_BARE) {
-		if (is_bare_repository() || is_inside_git_dir())
-			die("%s must be run in a work tree", p->cmd);
-	}
+	if ((p->option & NEED_WORK_TREE) &&
+	    (!is_inside_work_tree() || is_inside_git_dir()))
+		die("%s must be run in a work tree", p->cmd);
 	trace_argv_printf(argv, argc, "trace: built-in: git");
 
 	status = p->fn(argc, argv, prefix);
@@ -264,7 +273,7 @@ static void handle_internal_command(int argc, const char **argv)
 {
 	const char *cmd = argv[0];
 	static struct cmd_struct commands[] = {
-		{ "add", cmd_add, RUN_SETUP | NOT_BARE },
+		{ "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 		{ "annotate", cmd_annotate, RUN_SETUP | USE_PAGER },
 		{ "apply", cmd_apply },
 		{ "archive", cmd_archive },
@@ -274,9 +283,9 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "cat-file", cmd_cat_file, RUN_SETUP },
 		{ "checkout-index", cmd_checkout_index, RUN_SETUP },
 		{ "check-ref-format", cmd_check_ref_format },
-		{ "check-attr", cmd_check_attr, RUN_SETUP | NOT_BARE },
+		{ "check-attr", cmd_check_attr, RUN_SETUP | NEED_WORK_TREE },
 		{ "cherry", cmd_cherry, RUN_SETUP },
-		{ "cherry-pick", cmd_cherry_pick, RUN_SETUP | NOT_BARE },
+		{ "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 		{ "commit-tree", cmd_commit_tree, RUN_SETUP },
 		{ "config", cmd_config },
 		{ "count-objects", cmd_count_objects, RUN_SETUP },
@@ -304,7 +313,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "mailsplit", cmd_mailsplit },
 		{ "merge-base", cmd_merge_base, RUN_SETUP },
 		{ "merge-file", cmd_merge_file },
-		{ "mv", cmd_mv, RUN_SETUP | NOT_BARE },
+		{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 		{ "name-rev", cmd_name_rev, RUN_SETUP },
 		{ "pack-objects", cmd_pack_objects, RUN_SETUP },
 		{ "pickaxe", cmd_blame, RUN_SETUP | USE_PAGER },
@@ -317,9 +326,9 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "rerere", cmd_rerere, RUN_SETUP },
 		{ "rev-list", cmd_rev_list, RUN_SETUP },
 		{ "rev-parse", cmd_rev_parse, RUN_SETUP },
-		{ "revert", cmd_revert, RUN_SETUP | NOT_BARE },
-		{ "rm", cmd_rm, RUN_SETUP | NOT_BARE },
-		{ "runstatus", cmd_runstatus, RUN_SETUP | NOT_BARE },
+		{ "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
+		{ "rm", cmd_rm, RUN_SETUP | NEED_WORK_TREE },
+		{ "runstatus", cmd_runstatus, RUN_SETUP | NEED_WORK_TREE },
 		{ "shortlog", cmd_shortlog, RUN_SETUP | USE_PAGER },
 		{ "show-branch", cmd_show_branch, RUN_SETUP },
 		{ "show", cmd_show, RUN_SETUP | USE_PAGER },
diff --git a/setup.c b/setup.c
index 14f62c42e3..01f74d4644 100644
--- a/setup.c
+++ b/setup.c
@@ -95,7 +95,7 @@ void verify_non_filename(const char *prefix, const char *arg)
 	const char *name;
 	struct stat st;
 
-	if (is_inside_git_dir())
+	if (!is_inside_work_tree() || is_inside_git_dir())
 		return;
 	if (*arg == '-')
 		return; /* flag */
@@ -174,41 +174,96 @@ static int inside_git_dir = -1;
 
 int is_inside_git_dir(void)
 {
-	if (inside_git_dir < 0) {
-		char buffer[1024];
-
-		if (is_bare_repository())
-			return (inside_git_dir = 1);
-		if (getcwd(buffer, sizeof(buffer))) {
-			const char *git_dir = get_git_dir(), *cwd = buffer;
-			while (*git_dir && *git_dir == *cwd) {
-				git_dir++;
-				cwd++;
-			}
-			inside_git_dir = !*git_dir;
-		} else
-			inside_git_dir = 0;
+	if (inside_git_dir >= 0)
+		return inside_git_dir;
+	die("BUG: is_inside_git_dir called before setup_git_directory");
+}
+
+static int inside_work_tree = -1;
+
+int is_inside_work_tree(void)
+{
+	if (inside_git_dir >= 0)
+		return inside_work_tree;
+	die("BUG: is_inside_work_tree called before setup_git_directory");
+}
+
+static char *gitworktree_config;
+
+static int git_setup_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "core.worktree")) {
+		if (gitworktree_config)
+			strlcpy(gitworktree_config, value, PATH_MAX);
+		return 0;
 	}
-	return inside_git_dir;
+	return git_default_config(var, value);
 }
 
 const char *setup_git_directory_gently(int *nongit_ok)
 {
 	static char cwd[PATH_MAX+1];
-	const char *gitdirenv;
-	int len, offset;
+	char worktree[PATH_MAX+1], gitdir[PATH_MAX+1];
+	const char *gitdirenv, *gitworktree;
+	int wt_rel_gitdir = 0;
 
-	/*
-	 * If GIT_DIR is set explicitly, we're not going
-	 * to do any discovery, but we still do repository
-	 * validation.
-	 */
 	gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
-	if (gitdirenv) {
-		if (PATH_MAX - 40 < strlen(gitdirenv))
-			die("'$%s' too big", GIT_DIR_ENVIRONMENT);
-		if (is_git_directory(gitdirenv))
+	if (!gitdirenv) {
+		int len, offset;
+
+		if (!getcwd(cwd, sizeof(cwd)-1) || cwd[0] != '/')
+			die("Unable to read current working directory");
+
+		offset = len = strlen(cwd);
+		for (;;) {
+			if (is_git_directory(".git"))
+				break;
+			if (offset == 0) {
+				offset = -1;
+				break;
+			}
+			chdir("..");
+			while (cwd[--offset] != '/')
+				; /* do nothing */
+		}
+
+		if (offset >= 0) {
+			inside_work_tree = 1;
+			git_config(git_default_config);
+			if (offset == len) {
+				inside_git_dir = 0;
+				return NULL;
+			}
+
+			cwd[len++] = '/';
+			cwd[len] = '\0';
+			inside_git_dir = !prefixcmp(cwd + offset + 1, ".git/");
+			return cwd + offset + 1;
+		}
+
+		if (chdir(cwd))
+			die("Cannot come back to cwd");
+		if (!is_git_directory(".")) {
+			if (nongit_ok) {
+				*nongit_ok = 1;
+				return NULL;
+			}
+			die("Not a git repository");
+		}
+		setenv(GIT_DIR_ENVIRONMENT, cwd, 1);
+		gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
+		if (!gitdirenv)
+			die("getenv after setenv failed");
+	}
+
+	if (PATH_MAX - 40 < strlen(gitdirenv)) {
+		if (nongit_ok) {
+			*nongit_ok = 1;
 			return NULL;
+		}
+		die("$%s too big", GIT_DIR_ENVIRONMENT);
+	}
+	if (!is_git_directory(gitdirenv)) {
 		if (nongit_ok) {
 			*nongit_ok = 1;
 			return NULL;
@@ -218,41 +273,92 @@ const char *setup_git_directory_gently(int *nongit_ok)
 
 	if (!getcwd(cwd, sizeof(cwd)-1) || cwd[0] != '/')
 		die("Unable to read current working directory");
+	if (chdir(gitdirenv)) {
+		if (nongit_ok) {
+			*nongit_ok = 1;
+			return NULL;
+		}
+		die("Cannot change directory to $%s '%s'",
+			GIT_DIR_ENVIRONMENT, gitdirenv);
+	}
+	if (!getcwd(gitdir, sizeof(gitdir)-1) || gitdir[0] != '/')
+		die("Unable to read current working directory");
+	if (chdir(cwd))
+		die("Cannot come back to cwd");
 
-	offset = len = strlen(cwd);
-	for (;;) {
-		if (is_git_directory(".git"))
-			break;
-		chdir("..");
-		do {
-			if (!offset) {
-				if (is_git_directory(cwd)) {
-					if (chdir(cwd))
-						die("Cannot come back to cwd");
-					setenv(GIT_DIR_ENVIRONMENT, cwd, 1);
-					inside_git_dir = 1;
-					return NULL;
-				}
-				if (nongit_ok) {
-					if (chdir(cwd))
-						die("Cannot come back to cwd");
-					*nongit_ok = 1;
-					return NULL;
-				}
-				die("Not a git repository");
+	/*
+	 * In case there is a work tree we may change the directory,
+	 * therefore make GIT_DIR an absolute path.
+	 */
+	if (gitdirenv[0] != '/') {
+		setenv(GIT_DIR_ENVIRONMENT, gitdir, 1);
+		gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
+		if (!gitdirenv)
+			die("getenv after setenv failed");
+		if (PATH_MAX - 40 < strlen(gitdirenv)) {
+			if (nongit_ok) {
+				*nongit_ok = 1;
+				return NULL;
 			}
-		} while (cwd[--offset] != '/');
+			die("$%s too big after expansion to absolute path",
+				GIT_DIR_ENVIRONMENT);
+		}
+	}
+
+	strcat(cwd, "/");
+	strcat(gitdir, "/");
+	inside_git_dir = !prefixcmp(cwd, gitdir);
+
+	gitworktree = getenv(GIT_WORK_TREE_ENVIRONMENT);
+	if (!gitworktree) {
+		gitworktree_config = worktree;
+		worktree[0] = '\0';
+	}
+	git_config(git_setup_config);
+	if (!gitworktree) {
+		gitworktree_config = NULL;
+		if (worktree[0])
+			gitworktree = worktree;
+		if (gitworktree && gitworktree[0] != '/')
+			wt_rel_gitdir = 1;
+	}
+
+	if (wt_rel_gitdir && chdir(gitdirenv))
+		die("Cannot change directory to $%s '%s'",
+			GIT_DIR_ENVIRONMENT, gitdirenv);
+	if (gitworktree && chdir(gitworktree)) {
+		if (nongit_ok) {
+			if (wt_rel_gitdir && chdir(cwd))
+				die("Cannot come back to cwd");
+			*nongit_ok = 1;
+			return NULL;
+		}
+		if (wt_rel_gitdir)
+			die("Cannot change directory to working tree '%s'"
+				" from $%s", gitworktree, GIT_DIR_ENVIRONMENT);
+		else
+			die("Cannot change directory to working tree '%s'",
+				gitworktree);
 	}
+	if (!getcwd(worktree, sizeof(worktree)-1) || worktree[0] != '/')
+		die("Unable to read current working directory");
+	strcat(worktree, "/");
+	inside_work_tree = !prefixcmp(cwd, worktree);
 
-	if (offset == len)
+	if (gitworktree && inside_work_tree && !prefixcmp(worktree, gitdir) &&
+	    strcmp(worktree, gitdir)) {
+		inside_git_dir = 0;
+	}
+
+	if (!inside_work_tree) {
+		if (chdir(cwd))
+			die("Cannot come back to cwd");
 		return NULL;
+	}
 
-	/* Make "offset" point to past the '/', and add a '/' at the end */
-	offset++;
-	cwd[len++] = '/';
-	cwd[len] = 0;
-	inside_git_dir = !prefixcmp(cwd + offset, ".git/");
-	return cwd + offset;
+	if (!strcmp(cwd, worktree))
+		return NULL;
+	return cwd+strlen(worktree);
 }
 
 int git_config_perm(const char *var, const char *value)
diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh
new file mode 100755
index 0000000000..ec4996637d
--- /dev/null
+++ b/t/t1500-rev-parse.sh
@@ -0,0 +1,77 @@
+#!/bin/sh
+
+test_description='test git rev-parse'
+. ./test-lib.sh
+
+test_rev_parse() {
+	name=$1
+	shift
+
+	test_expect_success "$name: is-bare-repository" \
+	"test '$1' = \"\$(git rev-parse --is-bare-repository)\""
+	shift
+	[ $# -eq 0 ] && return
+
+	test_expect_success "$name: is-inside-git-dir" \
+	"test '$1' = \"\$(git rev-parse --is-inside-git-dir)\""
+	shift
+	[ $# -eq 0 ] && return
+
+	test_expect_success "$name: is-inside-work-tree" \
+	"test '$1' = \"\$(git rev-parse --is-inside-work-tree)\""
+	shift
+	[ $# -eq 0 ] && return
+
+	test_expect_success "$name: prefix" \
+	"test '$1' = \"\$(git rev-parse --show-prefix)\""
+	shift
+	[ $# -eq 0 ] && return
+}
+
+test_rev_parse toplevel false false true ''
+
+cd .git || exit 1
+test_rev_parse .git/ false true true .git/
+cd objects || exit 1
+test_rev_parse .git/objects/ false true true .git/objects/
+cd ../.. || exit 1
+
+mkdir -p sub/dir || exit 1
+cd sub/dir || exit 1
+test_rev_parse subdirectory false false true sub/dir/
+cd ../.. || exit 1
+
+git config core.bare true
+test_rev_parse 'core.bare = true' true false true
+
+git config --unset core.bare
+test_rev_parse 'core.bare undefined' false false true
+
+mkdir work || exit 1
+cd work || exit 1
+export GIT_DIR=../.git
+export GIT_CONFIG="$GIT_DIR"/config
+
+git config core.bare false
+test_rev_parse 'GIT_DIR=../.git, core.bare = false' false false true ''
+
+git config core.bare true
+test_rev_parse 'GIT_DIR=../.git, core.bare = true' true false true ''
+
+git config --unset core.bare
+test_rev_parse 'GIT_DIR=../.git, core.bare undefined' false false true ''
+
+mv ../.git ../repo.git || exit 1
+export GIT_DIR=../repo.git
+export GIT_CONFIG="$GIT_DIR"/config
+
+git config core.bare false
+test_rev_parse 'GIT_DIR=../repo.git, core.bare = false' false false true ''
+
+git config core.bare true
+test_rev_parse 'GIT_DIR=../repo.git, core.bare = true' true false true ''
+
+git config --unset core.bare
+test_rev_parse 'GIT_DIR=../repo.git, core.bare undefined' true false true ''
+
+test_done
diff --git a/t/t1501-worktree.sh b/t/t1501-worktree.sh
new file mode 100755
index 0000000000..aadeeab9ab
--- /dev/null
+++ b/t/t1501-worktree.sh
@@ -0,0 +1,92 @@
+#!/bin/sh
+
+test_description='test separate work tree'
+. ./test-lib.sh
+
+test_rev_parse() {
+	name=$1
+	shift
+
+	test_expect_success "$name: is-bare-repository" \
+	"test '$1' = \"\$(git rev-parse --is-bare-repository)\""
+	shift
+	[ $# -eq 0 ] && return
+
+	test_expect_success "$name: is-inside-git-dir" \
+	"test '$1' = \"\$(git rev-parse --is-inside-git-dir)\""
+	shift
+	[ $# -eq 0 ] && return
+
+	test_expect_success "$name: is-inside-work-tree" \
+	"test '$1' = \"\$(git rev-parse --is-inside-work-tree)\""
+	shift
+	[ $# -eq 0 ] && return
+
+	test_expect_success "$name: prefix" \
+	"test '$1' = \"\$(git rev-parse --show-prefix)\""
+	shift
+	[ $# -eq 0 ] && return
+}
+
+mkdir -p work/sub/dir || exit 1
+mv .git repo.git || exit 1
+
+say "core.worktree = relative path"
+export GIT_DIR=repo.git
+export GIT_CONFIG=$GIT_DIR/config
+unset GIT_WORK_TREE
+git config core.worktree ../work
+test_rev_parse 'outside'      false false false
+cd work || exit 1
+export GIT_DIR=../repo.git
+export GIT_CONFIG=$GIT_DIR/config
+test_rev_parse 'inside'       false false true ''
+cd sub/dir || exit 1
+export GIT_DIR=../../../repo.git
+export GIT_CONFIG=$GIT_DIR/config
+test_rev_parse 'subdirectory' false false true sub/dir/
+cd ../../.. || exit 1
+
+say "core.worktree = absolute path"
+export GIT_DIR=$(pwd)/repo.git
+export GIT_CONFIG=$GIT_DIR/config
+git config core.worktree "$(pwd)/work"
+test_rev_parse 'outside'      false false false
+cd work || exit 1
+test_rev_parse 'inside'       false false true ''
+cd sub/dir || exit 1
+test_rev_parse 'subdirectory' false false true sub/dir/
+cd ../../.. || exit 1
+
+say "GIT_WORK_TREE=relative path (override core.worktree)"
+export GIT_DIR=$(pwd)/repo.git
+export GIT_CONFIG=$GIT_DIR/config
+git config core.worktree non-existent
+export GIT_WORK_TREE=work
+test_rev_parse 'outside'      false false false
+cd work || exit 1
+export GIT_WORK_TREE=.
+test_rev_parse 'inside'       false false true ''
+cd sub/dir || exit 1
+export GIT_WORK_TREE=../..
+test_rev_parse 'subdirectory' false false true sub/dir/
+cd ../../.. || exit 1
+
+mv work repo.git/work
+
+say "GIT_WORK_TREE=absolute path, work tree below git dir"
+export GIT_DIR=$(pwd)/repo.git
+export GIT_CONFIG=$GIT_DIR/config
+export GIT_WORK_TREE=$(pwd)/repo.git/work
+test_rev_parse 'outside'              false false false
+cd repo.git || exit 1
+test_rev_parse 'in repo.git'              false true  false
+cd objects || exit 1
+test_rev_parse 'in repo.git/objects'      false true  false
+cd ../work || exit 1
+test_rev_parse 'in repo.git/work'         false false true ''
+cd sub/dir || exit 1
+test_rev_parse 'in repo.git/sub/dir' false false true sub/dir/
+cd ../../../.. || exit 1
+
+test_done
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 8bf4cf49a2..78d7e87e86 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -26,6 +26,7 @@ GIT_COMMITTER_EMAIL=committer@example.com
 GIT_COMMITTER_NAME='C O Mitter'
 unset GIT_DIFF_OPTS
 unset GIT_DIR
+unset GIT_WORK_TREE
 unset GIT_EXTERNAL_DIFF
 unset GIT_INDEX_FILE
 unset GIT_OBJECT_DIRECTORY