transport: drop support for git-over-rsync

The git-over-rsync protocol is inefficient and broken, and
has been for a long time. It transfers way more objects than
it needs (grabbing all of the remote's "objects/",
regardless of which objects we need). It does its own ad-hoc
parsing of loose and packed refs from the remote, but
doesn't properly override packed refs with loose ones,
leading to garbage results (e.g., expecting the other side
to have an object pointed to by a stale packed-refs entry,
or complaining that the other side has two copies of the
refs[1]).

This latter breakage means that nobody could have
successfully pulled from a moderately active repository
since cd547b4 (fetch/push: readd rsync support, 2007-10-01).

We never made an official deprecation notice in the release
notes for git's rsync protocol, but the tutorial has marked
it as such since 914328a (Update tutorial., 2005-08-30).
And on the mailing list as far back as Oct 2005, we can find
Junio mentioning it as having "been deprecated for quite
some time."[2,3,4]. So it was old news then; cogito had
deprecated the transport in July of 2005[5] (though it did
come back briefly when Linus broke git-http-pull!).

Of course some people professed their love of rsync through
2006, but Linus clarified in his usual gentle manner[6]:

  > Thanks!  This is why I still use rsync, even though
  > everybody and their mother tells me "Linus says rsync is
  > deprecated."

  No. You're using rsync because you're actively doing
  something _wrong_.

The deprecation sentiment was reinforced in 2008, with a
mention that cloning via rsync is broken (with no fix)[7].

Even the commit porting rsync over to C from shell (cd547b4)
lists it as deprecated! So between the 10 years of informal
warnings, and the fact that it has been severely broken
since 2007, it's probably safe to simply remove it without
further deprecation warnings.

[1] http://article.gmane.org/gmane.comp.version-control.git/285101
[2] http://article.gmane.org/gmane.comp.version-control.git/10093
[3] http://article.gmane.org/gmane.comp.version-control.git/17734
[4] http://article.gmane.org/gmane.comp.version-control.git/18911
[5] http://article.gmane.org/gmane.comp.version-control.git/5617
[6] http://article.gmane.org/gmane.comp.version-control.git/19354
[7] http://article.gmane.org/gmane.comp.version-control.git/103635

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 331 deletions

diff --git a/transport.c b/transport.c
index 67f3666..9da4e89 100644
--- a/transport.c
+++ b/transport.c
@@ -17,133 +17,6 @@
 #include "sha1-array.h"
 #include "sigchain.h"
 
-/* rsync support */
-
-/*
- * We copy packed-refs and refs/ into a temporary file, then read the
- * loose refs recursively (sorting whenever possible), and then inserting
- * those packed refs that are not yet in the list (not validating, but
- * assuming that the file is sorted).
- *
- * Appears refactoring this from refs.c is too cumbersome.
- */
-
-static int str_cmp(const void *a, const void *b)
-{
-	const char *s1 = a;
-	const char *s2 = b;
-
-	return strcmp(s1, s2);
-}
-
-/* path->buf + name_offset is expected to point to "refs/" */
-
-static int read_loose_refs(struct strbuf *path, int name_offset,
-		struct ref **tail)
-{
-	DIR *dir = opendir(path->buf);
-	struct dirent *de;
-	struct {
-		char **entries;
-		int nr, alloc;
-	} list;
-	int i, pathlen;
-
-	if (!dir)
-		return -1;
-
-	memset (&list, 0, sizeof(list));
-
-	while ((de = readdir(dir))) {
-		if (is_dot_or_dotdot(de->d_name))
-			continue;
-		ALLOC_GROW(list.entries, list.nr + 1, list.alloc);
-		list.entries[list.nr++] = xstrdup(de->d_name);
-	}
-	closedir(dir);
-
-	/* sort the list */
-
-	qsort(list.entries, list.nr, sizeof(char *), str_cmp);
-
-	pathlen = path->len;
-	strbuf_addch(path, '/');
-
-	for (i = 0; i < list.nr; i++, strbuf_setlen(path, pathlen + 1)) {
-		strbuf_addstr(path, list.entries[i]);
-		if (read_loose_refs(path, name_offset, tail)) {
-			int fd = open(path->buf, O_RDONLY);
-			char buffer[40];
-			struct ref *next;
-
-			if (fd < 0)
-				continue;
-			next = alloc_ref(path->buf + name_offset);
-			if (read_in_full(fd, buffer, 40) != 40 ||
-					get_oid_hex(buffer, &next->old_oid)) {
-				close(fd);
-				free(next);
-				continue;
-			}
-			close(fd);
-			(*tail)->next = next;
-			*tail = next;
-		}
-	}
-	strbuf_setlen(path, pathlen);
-
-	for (i = 0; i < list.nr; i++)
-		free(list.entries[i]);
-	free(list.entries);
-
-	return 0;
-}
-
-/* insert the packed refs for which no loose refs were found */
-
-static void insert_packed_refs(const char *packed_refs, struct ref **list)
-{
-	FILE *f = fopen(packed_refs, "r");
-	static char buffer[PATH_MAX];
-
-	if (!f)
-		return;
-
-	for (;;) {
-		int cmp = 0; /* assigned before used */
-		int len;
-
-		if (!fgets(buffer, sizeof(buffer), f)) {
-			fclose(f);
-			return;
-		}
-
-		if (!isxdigit(buffer[0]))
-			continue;
-		len = strlen(buffer);
-		if (len && buffer[len - 1] == '\n')
-			buffer[--len] = '\0';
-		if (len < 41)
-			continue;
-		while ((*list)->next &&
-				(cmp = strcmp(buffer + 41,
-				      (*list)->next->name)) > 0)
-			list = &(*list)->next;
-		if (!(*list)->next || cmp < 0) {
-			struct ref *next = alloc_ref(buffer + 41);
-			buffer[40] = '\0';
-			if (get_oid_hex(buffer, &next->old_oid)) {
-				warning ("invalid SHA-1: %s", buffer);
-				free(next);
-				continue;
-			}
-			next->next = (*list)->next;
-			(*list)->next = next;
-			list = &(*list)->next;
-		}
-	}
-}
-
 static void set_upstreams(struct transport *transport, struct ref *refs,
 	int pretend)
 {
@@ -192,205 +65,6 @@ static void set_upstreams(struct transport *transport, struct ref *refs,
 	}
 }
 
-static const char *rsync_url(const char *url)
-{
-	if (!starts_with(url, "rsync://"))
-		skip_prefix(url, "rsync:", &url);
-	return url;
-}
-
-static struct ref *get_refs_via_rsync(struct transport *transport, int for_push)
-{
-	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
-	struct ref dummy = {NULL}, *tail = &dummy;
-	struct child_process rsync = CHILD_PROCESS_INIT;
-	const char *args[5];
-	int temp_dir_len;
-
-	if (for_push)
-		return NULL;
-
-	/* copy the refs to the temporary directory */
-
-	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
-	if (!mkdtemp(temp_dir.buf))
-		die_errno ("Could not make temporary directory");
-	temp_dir_len = temp_dir.len;
-
-	strbuf_addstr(&buf, rsync_url(transport->url));
-	strbuf_addstr(&buf, "/refs");
-
-	rsync.argv = args;
-	rsync.stdout_to_stderr = 1;
-	args[0] = "rsync";
-	args[1] = (transport->verbose > 1) ? "-rv" : "-r";
-	args[2] = buf.buf;
-	args[3] = temp_dir.buf;
-	args[4] = NULL;
-
-	if (run_command(&rsync))
-		die ("Could not run rsync to get refs");
-
-	strbuf_reset(&buf);
-	strbuf_addstr(&buf, rsync_url(transport->url));
-	strbuf_addstr(&buf, "/packed-refs");
-
-	args[2] = buf.buf;
-
-	if (run_command(&rsync))
-		die ("Could not run rsync to get refs");
-
-	/* read the copied refs */
-
-	strbuf_addstr(&temp_dir, "/refs");
-	read_loose_refs(&temp_dir, temp_dir_len + 1, &tail);
-	strbuf_setlen(&temp_dir, temp_dir_len);
-
-	tail = &dummy;
-	strbuf_addstr(&temp_dir, "/packed-refs");
-	insert_packed_refs(temp_dir.buf, &tail);
-	strbuf_setlen(&temp_dir, temp_dir_len);
-
-	if (remove_dir_recursively(&temp_dir, 0))
-		warning ("Error removing temporary directory %s.",
-				temp_dir.buf);
-
-	strbuf_release(&buf);
-	strbuf_release(&temp_dir);
-
-	return dummy.next;
-}
-
-static int fetch_objs_via_rsync(struct transport *transport,
-				int nr_objs, struct ref **to_fetch)
-{
-	struct child_process rsync = CHILD_PROCESS_INIT;
-
-	rsync.stdout_to_stderr = 1;
-	argv_array_push(&rsync.args, "rsync");
-	argv_array_push(&rsync.args, (transport->verbose > 1) ? "-rv" : "-r");
-	argv_array_push(&rsync.args, "--ignore-existing");
-	argv_array_push(&rsync.args, "--exclude");
-	argv_array_push(&rsync.args, "info");
-	argv_array_pushf(&rsync.args, "%s/objects/", rsync_url(transport->url));
-	argv_array_push(&rsync.args, get_object_directory());
-
-	/* NEEDSWORK: handle one level of alternates */
-	return run_command(&rsync);
-}
-
-static int write_one_ref(const char *name, const struct object_id *oid,
-			 int flags, void *data)
-{
-	struct strbuf *buf = data;
-	int len = buf->len;
-
-	/* when called via for_each_ref(), flags is non-zero */
-	if (flags && !starts_with(name, "refs/heads/") &&
-			!starts_with(name, "refs/tags/"))
-		return 0;
-
-	strbuf_addstr(buf, name);
-	if (safe_create_leading_directories(buf->buf) ||
-	    write_file_gently(buf->buf, "%s", oid_to_hex(oid)))
-		return error("problems writing temporary file %s: %s",
-			     buf->buf, strerror(errno));
-	strbuf_setlen(buf, len);
-	return 0;
-}
-
-static int write_refs_to_temp_dir(struct strbuf *temp_dir,
-				  int refspec_nr, const char **refspec)
-{
-	int i;
-
-	for (i = 0; i < refspec_nr; i++) {
-		struct object_id oid;
-		char *ref;
-
-		if (dwim_ref(refspec[i], strlen(refspec[i]), oid.hash, &ref) != 1)
-			return error("Could not get ref %s", refspec[i]);
-
-		if (write_one_ref(ref, &oid, 0, temp_dir)) {
-			free(ref);
-			return -1;
-		}
-		free(ref);
-	}
-	return 0;
-}
-
-static int rsync_transport_push(struct transport *transport,
-		int refspec_nr, const char **refspec, int flags)
-{
-	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
-	int result = 0, i;
-	struct child_process rsync = CHILD_PROCESS_INIT;
-	const char *args[10];
-
-	if (flags & TRANSPORT_PUSH_MIRROR)
-		return error("rsync transport does not support mirror mode");
-
-	/* first push the objects */
-
-	strbuf_addstr(&buf, rsync_url(transport->url));
-	strbuf_addch(&buf, '/');
-
-	rsync.argv = args;
-	rsync.stdout_to_stderr = 1;
-	i = 0;
-	args[i++] = "rsync";
-	args[i++] = "-a";
-	if (flags & TRANSPORT_PUSH_DRY_RUN)
-		args[i++] = "--dry-run";
-	if (transport->verbose > 1)
-		args[i++] = "-v";
-	args[i++] = "--ignore-existing";
-	args[i++] = "--exclude";
-	args[i++] = "info";
-	args[i++] = get_object_directory();
-	args[i++] = buf.buf;
-	args[i++] = NULL;
-
-	if (run_command(&rsync))
-		return error("Could not push objects to %s",
-				rsync_url(transport->url));
-
-	/* copy the refs to the temporary directory; they could be packed. */
-
-	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
-	if (!mkdtemp(temp_dir.buf))
-		die_errno ("Could not make temporary directory");
-	strbuf_addch(&temp_dir, '/');
-
-	if (flags & TRANSPORT_PUSH_ALL) {
-		if (for_each_ref(write_one_ref, &temp_dir))
-			return -1;
-	} else if (write_refs_to_temp_dir(&temp_dir, refspec_nr, refspec))
-		return -1;
-
-	i = 2;
-	if (flags & TRANSPORT_PUSH_DRY_RUN)
-		args[i++] = "--dry-run";
-	if (!(flags & TRANSPORT_PUSH_FORCE))
-		args[i++] = "--ignore-existing";
-	args[i++] = temp_dir.buf;
-	args[i++] = rsync_url(transport->url);
-	args[i++] = NULL;
-	if (run_command(&rsync))
-		result = error("Could not push to %s",
-				rsync_url(transport->url));
-
-	if (remove_dir_recursively(&temp_dir, 0))
-		warning ("Could not remove temporary directory %s.",
-				temp_dir.buf);
-
-	strbuf_release(&buf);
-	strbuf_release(&temp_dir);
-
-	return result;
-}
-
 struct bundle_transport_data {
 	int fd;
 	struct bundle_header header;
@@ -984,11 +658,7 @@ struct transport *transport_get(struct remote *remote, const char *url)
 	if (helper) {
 		transport_helper_init(ret, helper);
 	} else if (starts_with(url, "rsync:")) {
-		transport_check_allowed("rsync");
-		ret->get_refs_list = get_refs_via_rsync;
-		ret->fetch = fetch_objs_via_rsync;
-		ret->push = rsync_transport_push;
-		ret->smart_options = NULL;
+		die("git-over-rsync is no longer supported");
 	} else if (url_is_local_not_ssh(url) && is_file(url) && is_bundle(url, 1)) {
 		struct bundle_transport_data *data = xcalloc(1, sizeof(*data));
 		transport_check_allowed("file");