diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt index f7dfe48d28..e2992f17a0 100644 --- a/Documentation/git-push.txt +++ b/Documentation/git-push.txt @@ -11,6 +11,7 @@ SYNOPSIS [verse] 'git push' [--all | --mirror | --tags] [--follow-tags] [-n | --dry-run] [--receive-pack=] [--repo=] [-f | --force] [--prune] [-v | --verbose] [-u | --set-upstream] + [--force-with-lease[=[:]]] [--no-verify] [ [...]] DESCRIPTION @@ -130,21 +131,75 @@ already exists on the remote side. repository over ssh, and you do not have the program in a directory on the default $PATH. +--[no-]force-with-lease:: +--force-with-lease=:: +--force-with-lease=::: + Usually, "git push" refuses to update a remote ref that is + not an ancestor of the local ref used to overwrite it. ++ +This option bypasses the check, but instead requires that the +current value of the ref to be the expected value. "git push" +fails otherwise. ++ +Imagine that you have to rebase what you have already published. +You will have to bypass the "must fast-forward" rule in order to +replace the history you originally published with the rebased history. +If somebody else built on top of your original history while you are +rebasing, the tip of the branch at the remote may advance with her +commit, and blindly pushing with `--force` will lose her work. ++ +This option allows you to say that you expect the history you are +updating is what you rebased and want to replace. If the remote ref +still points at the commit you specified, you can be sure that no +other people did anything to the ref (it is like taking a "lease" on +the ref without explicitly locking it, and you update the ref while +making sure that your earlier "lease" is still valid). ++ +`--force-with-lease` alone, without specifying the details, will protect +all remote refs that are going to be updated by requiring their +current value to be the same as the remote-tracking branch we have +for them, unless specified with a `--force-with-lease=:` +option that explicitly states what the expected value is. ++ +`--force-with-lease=`, without specifying the expected value, will +protect the named ref (alone), if it is going to be updated, by +requiring its current value to be the same as the remote-tracking +branch we have for it. ++ +`--force-with-lease=:` will protect the named ref (alone), +if it is going to be updated, by requiring its current value to be +the same as the specified value (which is allowed to be +different from the remote-tracking branch we have for the refname, +or we do not even have to have such a remote-tracking branch when +this form is used). ++ +Note that all forms other than `--force-with-lease=:` +that specifies the expected current value of the ref explicitly are +still experimental and their semantics may change as we gain experience +with this feature. ++ +"--no-force-with-lease" will cancel all the previous --force-with-lease on the +command line. + -f:: --force:: Usually, the command refuses to update a remote ref that is not an ancestor of the local ref used to overwrite it. - This flag disables the check. This can cause the - remote repository to lose commits; use it with care. - Note that `--force` applies to all the refs that are pushed, - hence using it with `push.default` set to `matching` or with - multiple push destinations configured with `remote.*.push` - may overwrite refs other than the current branch (including - local refs that are strictly behind their remote counterpart). - To force a push to only one branch, use a `+` in front of the - refspec to push (e.g `git push origin +master` to force a push - to the `master` branch). See the `...` section above - for details. + Also, when `--force-with-lease` option is used, the command refuses + to update a remote ref whose current value does not match + what is expected. ++ +This flag disables these checks, and can cause the remote repository +to lose commits; use it with care. ++ +Note that `--force` applies to all the refs that are pushed, hence +using it with `push.default` set to `matching` or with multiple push +destinations configured with `remote.*.push` may overwrite refs +other than the current branch (including local refs that are +strictly behind their remote counterpart). To force a push to only +one branch, use a `+` in front of the refspec to push (e.g `git push +origin +master` to force a push to the `master` branch). See the +`...` section above for details. --repo=:: This option is only relevant if no argument is diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c index 3e19d7149e..c8e858232a 100644 --- a/builtin/fetch-pack.c +++ b/builtin/fetch-pack.c @@ -1,6 +1,8 @@ #include "builtin.h" #include "pkt-line.h" #include "fetch-pack.h" +#include "remote.h" +#include "connect.h" static const char fetch_pack_usage[] = "git fetch-pack [--all] [--stdin] [--quiet|-q] [--keep|-k] [--thin] " diff --git a/builtin/push.c b/builtin/push.c index aff507c9f6..50bbfd62b1 100644 --- a/builtin/push.c +++ b/builtin/push.c @@ -21,6 +21,8 @@ static const char *receivepack; static int verbosity; static int progress = -1; +static struct push_cas_option cas; + static const char **refspec; static int refspec_nr; static int refspec_alloc; @@ -316,6 +318,13 @@ static int push_with_options(struct transport *transport, int flags) if (thin) transport_set_option(transport, TRANS_OPT_THIN, "yes"); + if (!is_empty_cas(&cas)) { + if (!transport->smart_options) + die("underlying transport does not support --%s option", + CAS_OPT_NAME); + transport->smart_options->cas = &cas; + } + if (verbosity > 0) fprintf(stderr, _("Pushing to %s\n"), transport->url); err = transport_push(transport, refspec_nr, refspec, flags, @@ -451,6 +460,10 @@ int cmd_push(int argc, const char **argv, const char *prefix) OPT_BIT('n' , "dry-run", &flags, N_("dry run"), TRANSPORT_PUSH_DRY_RUN), OPT_BIT( 0, "porcelain", &flags, N_("machine-readable output"), TRANSPORT_PUSH_PORCELAIN), OPT_BIT('f', "force", &flags, N_("force updates"), TRANSPORT_PUSH_FORCE), + { OPTION_CALLBACK, + 0, CAS_OPT_NAME, &cas, N_("refname>:next) - if (!strcmp(list->name, name)) - return (struct ref *)list; - return NULL; -} - /* * generate a format suitable for scanf from a ref_rev_parse_rules * rule, that is replace the "%.*s" spec with a "%s" spec diff --git a/remote-curl.c b/remote-curl.c index 6918668dc2..b5ebe01800 100644 --- a/remote-curl.c +++ b/remote-curl.c @@ -6,6 +6,7 @@ #include "exec_cmd.h" #include "run-command.h" #include "pkt-line.h" +#include "string-list.h" #include "sideband.h" #include "argv-array.h" @@ -22,6 +23,7 @@ struct options { thin : 1; }; static struct options options; +static struct string_list cas_options = STRING_LIST_INIT_DUP; static int set_option(const char *name, const char *value) { @@ -77,6 +79,13 @@ static int set_option(const char *name, const char *value) return -1; return 0; } + else if (!strcmp(name, "cas")) { + struct strbuf val = STRBUF_INIT; + strbuf_addf(&val, "--" CAS_OPT_NAME "=%s", value); + string_list_append(&cas_options, val.buf); + strbuf_release(&val); + return 0; + } else { return 1 /* unsupported */; } @@ -802,6 +811,7 @@ static int push_git(struct discovery *heads, int nr_spec, char **specs) struct rpc_state rpc; int i, err; struct argv_array args; + struct string_list_item *cas_option; argv_array_init(&args); argv_array_pushl(&args, "send-pack", "--stateless-rpc", "--helper-status", @@ -816,6 +826,8 @@ static int push_git(struct discovery *heads, int nr_spec, char **specs) else if (options.verbosity > 1) argv_array_push(&args, "--verbose"); argv_array_push(&args, options.progress ? "--progress" : "--no-progress"); + for_each_string_list_item(cas_option, &cas_options) + argv_array_push(&args, cas_option->string); argv_array_push(&args, url); for (i = 0; i < nr_spec; i++) argv_array_push(&args, specs[i]); diff --git a/remote.c b/remote.c index 8f0f2dd10e..24334679e0 100644 --- a/remote.c +++ b/remote.c @@ -1305,6 +1305,14 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds free(sent_tips.tip); } +struct ref *find_ref_by_name(const struct ref *list, const char *name) +{ + for ( ; list; list = list->next) + if (!strcmp(list->name, name)) + return (struct ref *)list; + return NULL; +} + static void prepare_ref_index(struct string_list *ref_index, struct ref *ref) { for ( ; ref; ref = ref->next) @@ -1414,12 +1422,13 @@ int match_push_refs(struct ref *src, struct ref **dst, } void set_ref_status_for_push(struct ref *remote_refs, int send_mirror, - int force_update) + int force_update) { struct ref *ref; for (ref = remote_refs; ref; ref = ref->next) { int force_ref_update = ref->force || force_update; + int reject_reason = 0; if (ref->peer_ref) hashcpy(ref->new_sha1, ref->peer_ref->new_sha1); @@ -1434,6 +1443,26 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror, } /* + * Bypass the usual "must fast-forward" check but + * replace it with a weaker "the old value must be + * this value we observed". If the remote ref has + * moved and is now different from what we expect, + * reject any push. + * + * It also is an error if the user told us to check + * with the remote-tracking branch to find the value + * to expect, but we did not have such a tracking + * branch. + */ + if (ref->expect_old_sha1) { + if (ref->expect_old_no_trackback || + hashcmp(ref->old_sha1, ref->old_sha1_expect)) + reject_reason = REF_STATUS_REJECT_STALE; + } + + /* + * The usual "must fast-forward" rules. + * * Decide whether an individual refspec A:B can be * pushed. The push will succeed if any of the * following are true: @@ -1451,24 +1480,26 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror, * passing the --force argument */ - if (!ref->deletion && !is_null_sha1(ref->old_sha1)) { - int why = 0; /* why would this push require --force? */ - + else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) { if (!prefixcmp(ref->name, "refs/tags/")) - why = REF_STATUS_REJECT_ALREADY_EXISTS; + reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS; else if (!has_sha1_file(ref->old_sha1)) - why = REF_STATUS_REJECT_FETCH_FIRST; + reject_reason = REF_STATUS_REJECT_FETCH_FIRST; else if (!lookup_commit_reference_gently(ref->old_sha1, 1) || !lookup_commit_reference_gently(ref->new_sha1, 1)) - why = REF_STATUS_REJECT_NEEDS_FORCE; + reject_reason = REF_STATUS_REJECT_NEEDS_FORCE; else if (!ref_newer(ref->new_sha1, ref->old_sha1)) - why = REF_STATUS_REJECT_NONFASTFORWARD; - - if (!force_ref_update) - ref->status = why; - else if (why) - ref->forced_update = 1; + reject_reason = REF_STATUS_REJECT_NONFASTFORWARD; } + + /* + * "--force" will defeat any rejection implemented + * by the rules above. + */ + if (!force_ref_update) + ref->status = reject_reason; + else if (reject_reason) + ref->forced_update = 1; } } @@ -1939,3 +1970,121 @@ struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fet string_list_clear(&ref_names, 0); return stale_refs; } + +/* + * Compare-and-swap + */ +void clear_cas_option(struct push_cas_option *cas) +{ + int i; + + for (i = 0; i < cas->nr; i++) + free(cas->entry[i].refname); + free(cas->entry); + memset(cas, 0, sizeof(*cas)); +} + +static struct push_cas *add_cas_entry(struct push_cas_option *cas, + const char *refname, + size_t refnamelen) +{ + struct push_cas *entry; + ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc); + entry = &cas->entry[cas->nr++]; + memset(entry, 0, sizeof(*entry)); + entry->refname = xmemdupz(refname, refnamelen); + return entry; +} + +int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset) +{ + const char *colon; + struct push_cas *entry; + + if (unset) { + /* "--no-