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-rw-r--r--Documentation/git-push.txt77
-rw-r--r--builtin/push.c6
-rw-r--r--builtin/send-pack.c17
-rw-r--r--remote.c57
-rw-r--r--remote.h22
5 files changed, 168 insertions, 11 deletions
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index f7dfe48..e2992f1 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=<git-receive-pack>]
[--repo=<repository>] [-f | --force] [--prune] [-v | --verbose] [-u | --set-upstream]
+ [--force-with-lease[=<refname>[:<expect>]]]
[--no-verify] [<repository> [<refspec>...]]
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=<refname>::
+--force-with-lease=<refname>:<expect>::
+ 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=<refname>:<expect>`
+option that explicitly states what the expected value is.
++
+`--force-with-lease=<refname>`, 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=<refname>:<expect>` 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 <expect> (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=<refname>:<expect>`
+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 `<refspec>...` 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
+`<refspec>...` section above for details.
--repo=<repository>::
This option is only relevant if no <repository> argument is
diff --git a/builtin/push.c b/builtin/push.c
index 342d792..31a5ba0 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;
@@ -432,6 +434,10 @@ 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>:<expect"),
+ N_("require old value of ref to be at this value"),
+ PARSE_OPT_OPTARG, parseopt_push_cas_option },
{ OPTION_CALLBACK, 0, "recurse-submodules", &flags, N_("check"),
N_("control recursive pushing of submodules"),
PARSE_OPT_OPTARG, option_parse_recurse_submodules },
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index e86d3b5..a23b26d 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -103,6 +103,7 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
int flags;
unsigned int reject_reasons;
int progress = -1;
+ struct push_cas_option cas = {0};
argv++;
for (i = 1; i < argc; i++, argv++) {
@@ -165,6 +166,22 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
helper_status = 1;
continue;
}
+ if (!strcmp(arg, "--" CAS_OPT_NAME)) {
+ if (parse_push_cas_option(&cas, NULL, 0) < 0)
+ exit(1);
+ continue;
+ }
+ if (!strcmp(arg, "--no-" CAS_OPT_NAME)) {
+ if (parse_push_cas_option(&cas, NULL, 1) < 0)
+ exit(1);
+ continue;
+ }
+ if (!prefixcmp(arg, "--" CAS_OPT_NAME "=")) {
+ if (parse_push_cas_option(&cas,
+ strchr(arg, '=') + 1, 1) < 0)
+ exit(1);
+ continue;
+ }
usage(send_pack_usage);
}
if (!dest) {
diff --git a/remote.c b/remote.c
index b1ff7a2..0d38353 100644
--- a/remote.c
+++ b/remote.c
@@ -1921,3 +1921,60 @@ 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-<option>" */
+ clear_cas_option(cas);
+ return 0;
+ }
+
+ if (!arg) {
+ /* just "--<option>" */
+ cas->use_tracking_for_rest = 1;
+ return 0;
+ }
+
+ /* "--<option>=refname" or "--<option>=refname:value" */
+ colon = strchrnul(arg, ':');
+ entry = add_cas_entry(cas, arg, colon - arg);
+ if (!*colon)
+ entry->use_tracking = 1;
+ else if (get_sha1(colon + 1, entry->expect))
+ return error("cannot parse expected object name '%s'", colon + 1);
+ return 0;
+}
+
+int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
+{
+ return parse_push_cas_option(opt->value, arg, unset);
+}
diff --git a/remote.h b/remote.h
index a850059..843c3ce 100644
--- a/remote.h
+++ b/remote.h
@@ -1,6 +1,8 @@
#ifndef REMOTE_H
#define REMOTE_H
+#include "parse-options.h"
+
enum {
REMOTE_CONFIG,
REMOTE_REMOTES,
@@ -226,4 +228,24 @@ struct ref *guess_remote_head(const struct ref *head,
/* Return refs which no longer exist on remote */
struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map);
+/*
+ * Compare-and-swap
+ */
+#define CAS_OPT_NAME "force-with-lease"
+
+struct push_cas_option {
+ unsigned use_tracking_for_rest:1;
+ struct push_cas {
+ unsigned char expect[20];
+ unsigned use_tracking:1;
+ char *refname;
+ } *entry;
+ int nr;
+ int alloc;
+};
+
+extern int parseopt_push_cas_option(const struct option *, const char *arg, int unset);
+extern int parse_push_cas_option(struct push_cas_option *, const char *arg, int unset);
+extern void clear_cas_option(struct push_cas_option *);
+
#endif