Merge branch 'ph/transport-with-gitfile'

* ph/transport-with-gitfile:
  Fix is_gitfile() for files too small or larger than PATH_MAX to be a gitfile
  Add test showing git-fetch groks gitfiles
  Teach transport about the gitfile mechanism
  Learn to handle gitfiles in enter_repo
  enter_repo: do not modify input

cache.h

@@ -736,7 +736,7 @@ int safe_create_leading_directories(char *path);
 int safe_create_leading_directories_const(const char *path);
 int mkdir_in_gitdir(const char *path);
 extern char *expand_user_path(const char *path);
-char *enter_repo(char *path, int strict);
+const char *enter_repo(const char *path, int strict);
 static inline int is_absolute_path(const char *path)
 {
 	return is_dir_sep(path[0]) || has_dos_drive_prefix(path);

daemon.c

@@ -108,11 +108,11 @@ static void NORETURN daemon_die(const char *err, va_list params)
 	exit(1);
 }
 
-static char *path_ok(char *directory)
+static const char *path_ok(char *directory)
 {
 	static char rpath[PATH_MAX];
 	static char interp_path[PATH_MAX];
-	char *path;
+	const char *path;
 	char *dir;
 
 	dir = directory;

path.c

@@ -283,7 +283,7 @@ return_null:
  * links.  User relative paths are also returned as they are given,
  * except DWIM suffixing.
  */
-char *enter_repo(char *path, int strict)
+const char *enter_repo(const char *path, int strict)
 {
 	static char used_path[PATH_MAX];
 	static char validated_path[PATH_MAX];
@@ -295,16 +295,19 @@ char *enter_repo(char *path, int strict)
 		static const char *suffix[] = {
 			".git/.git", "/.git", ".git", "", NULL,
 		};
+		const char *gitfile;
 		int len = strlen(path);
 		int i;
-		while ((1 < len) && (path[len-1] == '/')) {
-			path[len-1] = 0;
+		while ((1 < len) && (path[len-1] == '/'))
 			len--;
-		}
+
 		if (PATH_MAX <= len)
 			return NULL;
-		if (path[0] == '~') {
-			char *newpath = expand_user_path(path);
+		strncpy(used_path, path, len); used_path[len] = 0 ;
+		strcpy(validated_path, used_path);
+
+		if (used_path[0] == '~') {
+			char *newpath = expand_user_path(used_path);
 			if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
 				free(newpath);
 				return NULL;
@@ -316,24 +319,23 @@ char *enter_repo(char *path, int strict)
 			 * 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);
+		len = strlen(used_path);
 		for (i = 0; suffix[i]; i++) {
-			strcpy(path + len, suffix[i]);
-			if (!access(path, F_OK)) {
+			strcpy(used_path + len, suffix[i]);
+			if (!access(used_path, F_OK)) {
 				strcat(validated_path, suffix[i]);
 				break;
 			}
 		}
-		if (!suffix[i] || chdir(path))
+		if (!suffix[i])
+			return NULL;
+		gitfile = read_gitfile(used_path) ;
+		if (gitfile)
+			strcpy(used_path, gitfile);
+		if (chdir(used_path))
 			return NULL;
 		path = validated_path;
 	}

t/t5601-clone.sh

@@ -206,6 +206,20 @@ test_expect_success 'clone from .git file' '
 	git clone dst/.git dst2
 '
 
+test_expect_success 'fetch from .git gitfile' '
+	(
+		cd dst2 &&
+		git fetch ../dst/.git
+	)
+'
+
+test_expect_success 'fetch from gitfile parent' '
+	(
+		cd dst2 &&
+		git fetch ../dst
+	)
+'
+
 test_expect_success 'clone separate gitdir where target already exists' '
 	rm -rf dst &&
 	test_must_fail git clone --separate-git-dir realgitdir src dst

transport.c

@@ -859,6 +859,28 @@ static int is_local(const char *url)
 		has_dos_drive_prefix(url);
 }
 
+static int is_gitfile(const char *url)
+{
+	struct stat st;
+	char buf[9];
+	int fd, len;
+	if (stat(url, &st))
+		return 0;
+	if (!S_ISREG(st.st_mode))
+		return 0;
+	if (st.st_size < 10 || st.st_size > 9 + PATH_MAX)
+		return 0;
+
+	fd = open(url, O_RDONLY);
+	if (fd < 0)
+		die_errno("Error opening '%s'", url);
+	len = read_in_full(fd, buf, sizeof(buf));
+	close(fd);
+	if (len != sizeof(buf))
+		die("Error reading %s", url);
+	return !prefixcmp(buf, "gitdir: ");
+}
+
 static int is_file(const char *url)
 {
 	struct stat buf;
@@ -907,7 +929,7 @@ struct transport *transport_get(struct remote *remote, const char *url)
 		ret->fetch = fetch_objs_via_rsync;
 		ret->push = rsync_transport_push;
 		ret->smart_options = NULL;
-	} else if (is_local(url) && is_file(url)) {
+	} else if (is_local(url) && is_file(url) && !is_gitfile(url)) {
 		struct bundle_transport_data *data = xcalloc(1, sizeof(*data));
 		ret->data = data;
 		ret->get_refs_list = get_refs_from_bundle;