[PATCH v3 3/3] receive-pack: detect aliased updates which can occur with symrefs
- From
Jay Soffian <jaysoffian@gmail.com>
- Date
- Apr 19, 2010, 22:19 UTC
- Message-ID
- <1271715558-56781-1-git-send-email-jaysoffian@gmail.com>
- In-Reply-To
- <1271694343-31876-2-git-send-email-jaysoffian@gmail.com>
When pushing to a remote repo the sending side filters out aliased updates (e.g., foo:baz bar:baz). However, it is not possible for the sender to know if two refs are aliased on the receiving side via symrefs. Here is one such scenario:
$ git init origin $ (cd origin && touch file && git add file && git commit -a -m intial) $ git clone --bare origin origin.git $ rm -rf origin
$ git clone origin.git client
$ git clone --mirror client backup.git && $ (cd backup.git && git remote set-head origin --auto)
$ (cd client && git remote add --mirror backup ../backup.git && echo change1 > file && git commit -a -m change1 && git push origin && git push backup )
The push to backup fails with:
Counting objects: 5, done.
Writing objects: 100% (3/3), 244 bytes, done.
Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
error: Ref refs/remotes/origin/master is at ef3... but expected 262...
remote: error: failed to lock refs/remotes/origin/master
To ../backup.git
262cd57..ef307ff master -> master
262cd57..ef307ff origin/HEAD -> origin/HEAD
! [remote rejected] origin/master -> origin/master (failed to lock)
error: failed to push some refs to '../backup.git'The reason is that refs/remotes/origin/HEAD is a symref to refs/remotes/origin/master, but it is not possible for the sending side to unambiguously know this.
This commit fixes the issue by having receive-pack ignore any update to a symref whose target is being identically updated. If a symref and its target are being updated inconsistently, then the update for both fails with an error message ("refusing inconsistent update...") to help diagnose the situation.
Signed-off-by: Jay Soffian <jaysoffian@gmail.com> --- builtin-receive-pack.c | 68 +++++++++++++++++++++++++++++++++++++++++++++--- t/t5516-fetch-push.sh | 49 ++++++++++++++++++++++++++++++++++ 2 files changed, 113 insertions(+), 4 deletions(-)
diff --git a/builtin-receive-pack.c b/builtin-receive-pack.c index fffb6ea..bb34757 100644 --- a/builtin-receive-pack.c +++ b/builtin-receive-pack.c @@ -9,6 +9,7 @@ #include "object.h" #include "remote.h" #include "transport.h" +#include "string-list.h" static const char receive_pack_usage[] = "git receive-pack <git-dir>"; @@ -129,6 +130,7 @@ static void write_head_info(void) struct command { struct command *next; const char *error_string; + unsigned int skip_update; unsigned char old_sha1[20]; unsigned char new_sha1[20]; char ref_name[FLEX_ARRAY]; /* more */ @@ -486,6 +488,63 @@ static void run_update_post_hook(struct command *commands) } } +static void check_aliased_update(struct command *cmd, struct string_list *list) +{ + struct string_list_item *item; + struct command *dst_cmd; + unsigned char sha1[20]; + char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41]; + int flag; + + const char *dst_name = resolve_ref(cmd->ref_name, sha1, 0, &flag); + + if (!(flag & REF_ISSYMREF)) + return; + + if ((item = string_list_lookup(dst_name, list)) == NULL) + return; + + cmd->skip_update = 1; + + dst_cmd = (struct command *) item->util; + + if (!hashcmp(cmd->old_sha1, dst_cmd->old_sha1) && + !hashcmp(cmd->new_sha1, dst_cmd->new_sha1)) + return; + + dst_cmd->skip_update = 1; + + strcpy(cmd_oldh, find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV)); + strcat(cmd_newh, find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV)); + strcpy(dst_oldh, find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV)); + strcat(dst_newh, find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV)); + rp_error("refusing inconsistent update between symref '%s' (%s..%s) and" + " its target '%s' (%s..%s)", + cmd->ref_name, cmd_oldh, cmd_newh, + dst_cmd->ref_name, dst_oldh, dst_newh); + + cmd->error_string = dst_cmd->error_string = + "inconsistent aliased update"; +} + +static void check_aliased_updates(struct command *commands) +{ + struct command *cmd; + struct string_list ref_list = { NULL, 0, 0, 0 }; + + for (cmd = commands; cmd; cmd = cmd->next) { + struct string_list_item *item = + string_list_append(cmd->ref_name, &ref_list); + item->util = (void *)cmd; + } + sort_string_list(&ref_list); + + for (cmd = commands; cmd; cmd = cmd->next) + check_aliased_update(cmd, &ref_list); + + string_list_clear(&ref_list, 0); +} + static void execute_commands(struct command *commands, const char *unpacker_error) { struct command *cmd; @@ -503,10 +562,13 @@ static void execute_commands(struct command *commands, const char *unpacker_erro return; } + check_aliased_updates(commands); + head_name = resolve_ref("HEAD", sha1, 0, NULL); for (cmd = commands; cmd; cmd = cmd->next) - cmd->error_string = update(cmd); + if (!cmd->skip_update) + cmd->error_string = update(cmd); } static struct command *read_head_info(void) @@ -541,12 +603,10 @@ static struct command *read_head_info(void) if (strstr(refname + reflen + 1, "side-band-64k")) use_sideband = LARGE_PACKET_MAX; } - cmd = xmalloc(sizeof(struct command) + len - 80); + cmd = xcalloc(1, sizeof(struct command) + len - 80); hashcpy(cmd->old_sha1, old_sha1); hashcpy(cmd->new_sha1, new_sha1); memcpy(cmd->ref_name, line + 82, len - 81); - cmd->error_string = NULL; - cmd->next = NULL; *p = cmd; p = &cmd->next; } diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh index 3148789..f0813e0 100755 --- a/t/t5516-fetch-push.sh +++ b/t/t5516-fetch-push.sh @@ -683,4 +683,53 @@ test_expect_success 'push with branches containing #' ' git checkout master ' +test_expect_success 'push into aliased refs (consistent)' ' + mk_test heads/master && + mk_child child1 && + mk_child child2 && + ( + cd child1 && + git branch foo && + git symbolic-ref refs/heads/bar refs/heads/foo + git config receive.denyCurrentBranch false + ) && + ( + cd child2 && + >path2 && + git add path2 && + test_tick && + git commit -a -m child2 && + git branch foo && + git branch bar && + git push ../child1 foo bar + ) +' + +test_expect_success 'push into aliased refs (inconsistent)' ' + mk_test heads/master && + mk_child child1 && + mk_child child2 && + ( + cd child1 && + git branch foo && + git symbolic-ref refs/heads/bar refs/heads/foo + git config receive.denyCurrentBranch false + ) && + ( + cd child2 && + >path2 && + git add path2 && + test_tick && + git commit -a -m child2 && + git branch foo && + >path3 && + git add path3 && + test_tick && + git commit -a -m child2 && + git branch bar && + test_must_fail git push ../child1 foo bar 2>stderr && + grep "refusing inconsistent update" stderr + ) +' + test_done
-- 1.7.0.3.436.g2b878