git/builtin/update-ref.c

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#include "builtin.h"
#include "config.h"
#include "gettext.h"
#include "hash.h"
#include "refs.h"
#include "object-name.h"
#include "parse-options.h"
#include "quote.h"
#include "repository.h"
#include "strvec.h"
static const char * const git_update_ref_usage[] = {
N_("git update-ref [<options>] -d <refname> [<old-val>]"),
N_("git update-ref [<options>] <refname> <new-val> [<old-val>]"),
N_("git update-ref [<options>] --stdin [-z]"),
NULL
};
static char line_termination = '\n';
static unsigned int update_flags;
static unsigned int default_flags;
static unsigned create_reflog_flag;
static const char *msg;
/*
* Parse one whitespace- or NUL-terminated, possibly C-quoted argument
* and append the result to arg. Return a pointer to the terminator.
* Die if there is an error in how the argument is C-quoted. This
* function is only used if not -z.
*/
static const char *parse_arg(const char *next, struct strbuf *arg)
{
if (*next == '"') {
const char *orig = next;
if (unquote_c_style(arg, next, &next))
die("badly quoted argument: %s", orig);
if (*next && !isspace(*next))
die("unexpected character after quoted argument: %s", orig);
} else {
while (*next && !isspace(*next))
strbuf_addch(arg, *next++);
}
return next;
}
/*
* Parse the reference name immediately after "command SP". If not
* -z, then handle C-quoting. Return a pointer to a newly allocated
* string containing the name of the reference, or NULL if there was
* an error. Update *next to point at the character that terminates
* the argument. Die if C-quoting is malformed or the reference name
* is invalid.
*/
static char *parse_refname(const char **next)
{
struct strbuf ref = STRBUF_INIT;
if (line_termination) {
/* Without -z, use the next argument */
*next = parse_arg(*next, &ref);
} else {
/* With -z, use everything up to the next NUL */
strbuf_addstr(&ref, *next);
*next += ref.len;
}
if (!ref.len) {
strbuf_release(&ref);
return NULL;
}
if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
die("invalid ref format: %s", ref.buf);
return strbuf_detach(&ref, NULL);
}
/*
* The value being parsed is <oldvalue> (as opposed to <newvalue>; the
* difference affects which error messages are generated):
*/
#define PARSE_SHA1_OLD 0x01
/*
* For backwards compatibility, accept an empty string for update's
* <newvalue> in binary mode to be equivalent to specifying zeros.
*/
#define PARSE_SHA1_ALLOW_EMPTY 0x02
/*
* Parse an argument separator followed by the next argument, if any.
* If there is an argument, convert it to a SHA-1, write it to sha1,
* set *next to point at the character terminating the argument, and
* return 0. If there is no argument at all (not even the empty
* string), return 1 and leave *next unchanged. If the value is
* provided but cannot be converted to a SHA-1, die. flags can
* include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
*/
static int parse_next_oid(const char **next, const char *end,
struct object_id *oid,
const char *command, const char *refname,
int flags)
{
struct strbuf arg = STRBUF_INIT;
int ret = 0;
if (*next == end)
goto eof;
if (line_termination) {
/* Without -z, consume SP and use next argument */
if (!**next || **next == line_termination)
return 1;
if (**next != ' ')
die("%s %s: expected SP but got: %s",
command, refname, *next);
(*next)++;
*next = parse_arg(*next, &arg);
if (arg.len) {
if (repo_get_oid(the_repository, arg.buf, oid))
goto invalid;
} else {
/* Without -z, an empty value means all zeros: */
oidclr(oid);
}
} else {
/* With -z, read the next NUL-terminated line */
if (**next)
die("%s %s: expected NUL but got: %s",
command, refname, *next);
(*next)++;
if (*next == end)
goto eof;
strbuf_addstr(&arg, *next);
*next += arg.len;
if (arg.len) {
if (repo_get_oid(the_repository, arg.buf, oid))
goto invalid;
} else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
/* With -z, treat an empty value as all zeros: */
warning("%s %s: missing <newvalue>, treating as zero",
command, refname);
oidclr(oid);
} else {
/*
* With -z, an empty non-required value means
* unspecified:
*/
ret = 1;
}
}
strbuf_release(&arg);
return ret;
invalid:
die(flags & PARSE_SHA1_OLD ?
"%s %s: invalid <oldvalue>: %s" :
"%s %s: invalid <newvalue>: %s",
command, refname, arg.buf);
eof:
die(flags & PARSE_SHA1_OLD ?
"%s %s: unexpected end of input when reading <oldvalue>" :
"%s %s: unexpected end of input when reading <newvalue>",
command, refname);
}
/*
* The following five parse_cmd_*() functions parse the corresponding
* command. In each case, next points at the character following the
* command name and the following space. They each return a pointer
* to the character terminating the command, and die with an
* explanatory message if there are any parsing problems. All of
* these functions handle either text or binary format input,
* depending on how line_termination is set.
*/
static void parse_cmd_update(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf err = STRBUF_INIT;
char *refname;
struct object_id new_oid, old_oid;
int have_old;
refname = parse_refname(&next);
if (!refname)
die("update: missing <ref>");
if (parse_next_oid(&next, end, &new_oid, "update", refname,
PARSE_SHA1_ALLOW_EMPTY))
die("update %s: missing <newvalue>", refname);
have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
PARSE_SHA1_OLD);
if (*next != line_termination)
die("update %s: extra input: %s", refname, next);
if (ref_transaction_update(transaction, refname,
&new_oid, have_old ? &old_oid : NULL,
update_flags | create_reflog_flag,
msg, &err))
die("%s", err.buf);
update_flags = default_flags;
free(refname);
strbuf_release(&err);
}
static void parse_cmd_create(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf err = STRBUF_INIT;
char *refname;
struct object_id new_oid;
refname = parse_refname(&next);
if (!refname)
die("create: missing <ref>");
if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
die("create %s: missing <newvalue>", refname);
if (is_null_oid(&new_oid))
die("create %s: zero <newvalue>", refname);
if (*next != line_termination)
die("create %s: extra input: %s", refname, next);
if (ref_transaction_create(transaction, refname, &new_oid,
update_flags | create_reflog_flag,
msg, &err))
die("%s", err.buf);
update_flags = default_flags;
free(refname);
strbuf_release(&err);
}
static void parse_cmd_delete(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf err = STRBUF_INIT;
char *refname;
struct object_id old_oid;
int have_old;
refname = parse_refname(&next);
if (!refname)
die("delete: missing <ref>");
if (parse_next_oid(&next, end, &old_oid, "delete", refname,
PARSE_SHA1_OLD)) {
have_old = 0;
} else {
if (is_null_oid(&old_oid))
die("delete %s: zero <oldvalue>", refname);
have_old = 1;
}
if (*next != line_termination)
die("delete %s: extra input: %s", refname, next);
if (ref_transaction_delete(transaction, refname,
have_old ? &old_oid : NULL,
update_flags, msg, &err))
die("%s", err.buf);
update_flags = default_flags;
free(refname);
strbuf_release(&err);
}
static void parse_cmd_verify(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf err = STRBUF_INIT;
char *refname;
struct object_id old_oid;
refname = parse_refname(&next);
if (!refname)
die("verify: missing <ref>");
if (parse_next_oid(&next, end, &old_oid, "verify", refname,
PARSE_SHA1_OLD))
oidclr(&old_oid);
if (*next != line_termination)
die("verify %s: extra input: %s", refname, next);
if (ref_transaction_verify(transaction, refname, &old_oid,
update_flags, &err))
die("%s", err.buf);
update_flags = default_flags;
free(refname);
strbuf_release(&err);
}
static void report_ok(const char *command)
{
fprintf(stdout, "%s: ok\n", command);
fflush(stdout);
}
static void parse_cmd_option(struct ref_transaction *transaction,
const char *next, const char *end)
{
const char *rest;
if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
update_flags |= REF_NO_DEREF;
else
die("option unknown: %s", next);
}
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
static void parse_cmd_start(struct ref_transaction *transaction,
const char *next, const char *end)
{
if (*next != line_termination)
die("start: extra input: %s", next);
report_ok("start");
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
}
static void parse_cmd_prepare(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf error = STRBUF_INIT;
if (*next != line_termination)
die("prepare: extra input: %s", next);
if (ref_transaction_prepare(transaction, &error))
die("prepare: %s", error.buf);
report_ok("prepare");
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
}
static void parse_cmd_abort(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf error = STRBUF_INIT;
if (*next != line_termination)
die("abort: extra input: %s", next);
if (ref_transaction_abort(transaction, &error))
die("abort: %s", error.buf);
report_ok("abort");
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
}
static void parse_cmd_commit(struct ref_transaction *transaction,
const char *next, const char *end)
{
struct strbuf error = STRBUF_INIT;
if (*next != line_termination)
die("commit: extra input: %s", next);
if (ref_transaction_commit(transaction, &error))
die("commit: %s", error.buf);
report_ok("commit");
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
ref_transaction_free(transaction);
}
enum update_refs_state {
/* Non-transactional state open for updates. */
UPDATE_REFS_OPEN,
/* A transaction has been started. */
UPDATE_REFS_STARTED,
/* References are locked and ready for commit */
UPDATE_REFS_PREPARED,
/* Transaction has been committed or closed. */
UPDATE_REFS_CLOSED,
};
static const struct parse_cmd {
const char *prefix;
void (*fn)(struct ref_transaction *, const char *, const char *);
unsigned args;
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
enum update_refs_state state;
} command[] = {
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
{ "update", parse_cmd_update, 3, UPDATE_REFS_OPEN },
{ "create", parse_cmd_create, 2, UPDATE_REFS_OPEN },
{ "delete", parse_cmd_delete, 2, UPDATE_REFS_OPEN },
{ "verify", parse_cmd_verify, 2, UPDATE_REFS_OPEN },
{ "option", parse_cmd_option, 1, UPDATE_REFS_OPEN },
{ "start", parse_cmd_start, 0, UPDATE_REFS_STARTED },
{ "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
{ "abort", parse_cmd_abort, 0, UPDATE_REFS_CLOSED },
{ "commit", parse_cmd_commit, 0, UPDATE_REFS_CLOSED },
};
static void update_refs_stdin(void)
{
struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
enum update_refs_state state = UPDATE_REFS_OPEN;
struct ref_transaction *transaction;
int i, j;
transaction = ref_transaction_begin(&err);
if (!transaction)
die("%s", err.buf);
/* Read each line dispatch its command */
while (!strbuf_getwholeline(&input, stdin, line_termination)) {
const struct parse_cmd *cmd = NULL;
if (*input.buf == line_termination)
die("empty command in input");
else if (isspace(*input.buf))
die("whitespace before command: %s", input.buf);
for (i = 0; i < ARRAY_SIZE(command); i++) {
const char *prefix = command[i].prefix;
char c;
if (!starts_with(input.buf, prefix))
continue;
/*
* If the command has arguments, verify that it's
* followed by a space. Otherwise, it shall be followed
* by a line terminator.
*/
c = command[i].args ? ' ' : line_termination;
if (input.buf[strlen(prefix)] != c)
continue;
cmd = &command[i];
break;
}
if (!cmd)
die("unknown command: %s", input.buf);
/*
* Read additional arguments if NUL-terminated. Do not raise an
* error in case there is an early EOF to let the command
* handle missing arguments with a proper error message.
*/
for (j = 1; line_termination == '\0' && j < cmd->args; j++)
if (strbuf_appendwholeline(&input, stdin, line_termination))
break;
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
switch (state) {
case UPDATE_REFS_OPEN:
case UPDATE_REFS_STARTED:
if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
die("cannot restart ongoing transaction");
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
/* Do not downgrade a transaction to a non-transaction. */
if (cmd->state >= state)
state = cmd->state;
break;
case UPDATE_REFS_PREPARED:
if (cmd->state != UPDATE_REFS_CLOSED)
die("prepared transactions can only be closed");
state = cmd->state;
break;
case UPDATE_REFS_CLOSED:
if (cmd->state != UPDATE_REFS_STARTED)
die("transaction is closed");
/*
* Open a new transaction if we're currently closed and
* get a "start".
*/
state = cmd->state;
transaction = ref_transaction_begin(&err);
if (!transaction)
die("%s", err.buf);
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
break;
}
cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
input.buf + input.len);
}
update-ref: implement interactive transaction handling The git-update-ref(1) command can only handle queueing transactions right now via its "--stdin" parameter, but there is no way for users to handle the transaction itself in a more explicit way. E.g. in a replicated scenario, one may imagine a coordinator that spawns git-update-ref(1) for multiple repositories and only if all agree that an update is possible will the coordinator send a commit. Such a transactional session could look like > start < start: ok > update refs/heads/master $OLD $NEW > prepare < prepare: ok # All nodes have returned "ok" > commit < commit: ok or > start < start: ok > create refs/heads/master $OLD $NEW > prepare < fatal: cannot lock ref 'refs/heads/master': reference already exists # On all other nodes: > abort < abort: ok In order to allow for such transactional sessions, this commit introduces four new commands for git-update-ref(1), which matches those we have internally already with the exception of "start": - start: start a new transaction - prepare: prepare the transaction, that is try to lock all references and verify their current value matches the expected one - commit: explicitly commit a session, that is update references to match their new expected state - abort: abort a session and roll back all changes By design, git-update-ref(1) will commit as soon as standard input is being closed. While fine in a non-transactional world, it is definitely unexpected in a transactional world. Because of this, as soon as any of the new transactional commands is used, the default will change to aborting without an explicit "commit". To avoid a race between queueing updates and the first "prepare" that starts a transaction, the "start" command has been added to start an explicit transaction. Add some tests to exercise this new functionality. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-02 07:10:02 +00:00
switch (state) {
case UPDATE_REFS_OPEN:
/* Commit by default if no transaction was requested. */
if (ref_transaction_commit(transaction, &err))
die("%s", err.buf);
ref_transaction_free(transaction);
break;
case UPDATE_REFS_STARTED:
case UPDATE_REFS_PREPARED:
/* If using a transaction, we want to abort it. */
if (ref_transaction_abort(transaction, &err))
die("%s", err.buf);
break;
case UPDATE_REFS_CLOSED:
/* Otherwise no need to do anything, the transaction was closed already. */
break;
}
strbuf_release(&err);
strbuf_release(&input);
}
int cmd_update_ref(int argc, const char **argv, const char *prefix)
{
const char *refname, *oldval;
struct object_id oid, oldoid;
int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
int create_reflog = 0;
struct option options[] = {
OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
OPT_BOOL( 0 , "no-deref", &no_deref,
N_("update <refname> not the one it points to")),
OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
OPT_END(),
};
git_config(git_default_config, NULL);
argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
0);
if (msg && !*msg)
die("Refusing to perform update with empty message.");
create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
if (no_deref) {
default_flags = REF_NO_DEREF;
update_flags = default_flags;
}
if (read_stdin) {
if (delete || argc > 0)
usage_with_options(git_update_ref_usage, options);
if (end_null)
line_termination = '\0';
update_refs_stdin();
return 0;
}
if (end_null)
usage_with_options(git_update_ref_usage, options);
if (delete) {
if (argc < 1 || argc > 2)
usage_with_options(git_update_ref_usage, options);
refname = argv[0];
oldval = argv[1];
} else {
const char *value;
if (argc < 2 || argc > 3)
usage_with_options(git_update_ref_usage, options);
refname = argv[0];
value = argv[1];
oldval = argv[2];
if (repo_get_oid(the_repository, value, &oid))
die("%s: not a valid SHA1", value);
}
if (oldval) {
if (!*oldval)
/*
* The empty string implies that the reference
* must not already exist:
*/
oidclr(&oldoid);
else if (repo_get_oid(the_repository, oldval, &oldoid))
die("%s: not a valid old SHA1", oldval);
}
if (delete)
delete_ref(): use the usual convention for old_sha1 The ref_transaction_update() family of functions use the following convention for their old_sha1 parameters: * old_sha1 == NULL: Don't check the old value at all. * is_null_sha1(old_sha1): Ensure that the reference didn't exist before the transaction. * otherwise: Ensure that the reference had the specified value before the transaction. delete_ref() had a different convention, namely treating is_null_sha1(old_sha1) as "don't care". Change it to adhere to the standard convention to reduce the scope for confusion. Please note that it is now a bug to pass old_sha1=NULL_SHA1 to delete_ref() (because it doesn't make sense to delete a reference that you already know doesn't exist). This is consistent with the behavior of ref_transaction_delete(). Most of the callers of delete_ref() never pass old_sha1=NULL_SHA1 to delete_ref(), and are therefore unaffected by this change. The two exceptions are: * The call in cmd_update_ref(), which passed NULL_SHA1 if the old value passed in on the command line was 0{40} or the empty string. Change that caller to pass NULL in those cases. Arguably, it should be an error to call "update-ref -d" with the old value set to "does not exist", just as it is for the `--stdin` command "delete". But since this usage was accepted until now, continue to accept it. * The call in delete_branches(), which could pass NULL_SHA1 if deleting a broken or symbolic ref. Change it to pass NULL in these cases. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-22 14:03:10 +00:00
/*
* For purposes of backwards compatibility, we treat
* NULL_SHA1 as "don't care" here:
*/
return delete_ref(msg, refname,
(oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
default_flags);
else
return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
default_flags | create_reflog_flag,
UPDATE_REFS_DIE_ON_ERR);
}