builtin/update-ref.c - git - Git at Google

 #include "cache.h"
 #include "refs.h"
 #include "builtin.h"
 #include "parse-options.h"
 #include "quote.h"
 #include "argv-array.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 int update_flags;
 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(struct strbuf *input, 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_sha1(struct strbuf *input, const char **next,
 			   unsigned char *sha1,
 			   const char *command, const char *refname,
 			   int flags)
 {
 	struct strbuf arg = STRBUF_INIT;
 	int ret = 0;

 	if (*next == input->buf + input->len)
 		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 (get_sha1(arg.buf, sha1))
 				goto invalid;
 		} else {
 			/* Without -z, an empty value means all zeros: */
 			hashclr(sha1);
 		}
 	} 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 == input->buf + input->len)
 			goto eof;
 		strbuf_addstr(&arg, *next);
 		*next += arg.len;

 		if (arg.len) {
 			if (get_sha1(arg.buf, sha1))
 				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);
 			hashclr(sha1);
 		} 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 const char *parse_cmd_update(struct ref_transaction *transaction,
 				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 	unsigned char old_sha1[20];
 	int have_old;

 	refname = parse_refname(input, &next);
 	if (!refname)
 		die("update: missing <ref>");

 	if (parse_next_sha1(input, &next, new_sha1, "update", refname,
 			    PARSE_SHA1_ALLOW_EMPTY))
 		die("update %s: missing <newvalue>", refname);

 	have_old = !parse_next_sha1(input, &next, old_sha1, "update", refname,
 				    PARSE_SHA1_OLD);

 	if (*next != line_termination)
 		die("update %s: extra input: %s", refname, next);

 	if (ref_transaction_update(transaction, refname,
 				   new_sha1, have_old ? old_sha1 : NULL,
 				   update_flags, msg, &err))
 		die("%s", err.buf);

 	update_flags = 0;
 	free(refname);
 	strbuf_release(&err);

 	return next;
 }

 static const char *parse_cmd_create(struct ref_transaction *transaction,
 				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];

 	refname = parse_refname(input, &next);
 	if (!refname)
 		die("create: missing <ref>");

 	if (parse_next_sha1(input, &next, new_sha1, "create", refname, 0))
 		die("create %s: missing <newvalue>", refname);

 	if (is_null_sha1(new_sha1))
 		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_sha1,
 				   update_flags, msg, &err))
 		die("%s", err.buf);

 	update_flags = 0;
 	free(refname);
 	strbuf_release(&err);

 	return next;
 }

 static const char *parse_cmd_delete(struct ref_transaction *transaction,
 				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char old_sha1[20];
 	int have_old;

 	refname = parse_refname(input, &next);
 	if (!refname)
 		die("delete: missing <ref>");

 	if (parse_next_sha1(input, &next, old_sha1, "delete", refname,
 			    PARSE_SHA1_OLD)) {
 		have_old = 0;
 	} else {
 		if (is_null_sha1(old_sha1))
 			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_sha1 : NULL,
 				   update_flags, msg, &err))
 		die("%s", err.buf);

 	update_flags = 0;
 	free(refname);
 	strbuf_release(&err);

 	return next;
 }

 static const char *parse_cmd_verify(struct ref_transaction *transaction,
 				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char old_sha1[20];

 	refname = parse_refname(input, &next);
 	if (!refname)
 		die("verify: missing <ref>");

 	if (parse_next_sha1(input, &next, old_sha1, "verify", refname,
 			    PARSE_SHA1_OLD))
 		hashclr(old_sha1);

 	if (*next != line_termination)
 		die("verify %s: extra input: %s", refname, next);

 	if (ref_transaction_verify(transaction, refname, old_sha1,
 				   update_flags, &err))
 		die("%s", err.buf);

 	update_flags = 0;
 	free(refname);
 	strbuf_release(&err);

 	return next;
 }

 static const char *parse_cmd_option(struct strbuf *input, const char *next)
 {
 	if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
 		update_flags |= REF_NODEREF;
 	else
 		die("option unknown: %s", next);
 	return next + 8;
 }

 static void update_refs_stdin(struct ref_transaction *transaction)
 {
 	struct strbuf input = STRBUF_INIT;
 	const char *next;

 	if (strbuf_read(&input, 0, 1000) < 0)
 		die_errno("could not read from stdin");
 	next = input.buf;
 	/* Read each line dispatch its command */
 	while (next < input.buf + input.len) {
 		if (*next == line_termination)
 			die("empty command in input");
 		else if (isspace(*next))
 			die("whitespace before command: %s", next);
 		else if (starts_with(next, "update "))
 			next = parse_cmd_update(transaction, &input, next + 7);
 		else if (starts_with(next, "create "))
 			next = parse_cmd_create(transaction, &input, next + 7);
 		else if (starts_with(next, "delete "))
 			next = parse_cmd_delete(transaction, &input, next + 7);
 		else if (starts_with(next, "verify "))
 			next = parse_cmd_verify(transaction, &input, next + 7);
 		else if (starts_with(next, "option "))
 			next = parse_cmd_option(&input, next + 7);
 		else
 			die("unknown command: %s", next);

 		next++;
 	}

 	strbuf_release(&input);
 }

 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 {
 	const char *refname, *oldval;
 	unsigned char sha1[20], oldsha1[20];
 	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 	unsigned int flags = 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_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.");

 	if (read_stdin) {
 		struct strbuf err = STRBUF_INIT;
 		struct ref_transaction *transaction;

 		transaction = ref_transaction_begin(&err);
 		if (!transaction)
 			die("%s", err.buf);
 		if (delete || no_deref || argc > 0)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
 			line_termination = '\0';
 		update_refs_stdin(transaction);
 		if (ref_transaction_commit(transaction, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);
 		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 (get_sha1(value, sha1))
 			die("%s: not a valid SHA1", value);
 	}

 	hashclr(oldsha1); /* all-zero hash in case oldval is the empty string */
 	if (oldval && *oldval && get_sha1(oldval, oldsha1))
 		die("%s: not a valid old SHA1", oldval);

 	if (no_deref)
 		flags = REF_NODEREF;
 	if (delete)
 		return delete_ref(refname, oldval ? oldsha1 : NULL, flags);
 	else
 		return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
 				  flags, UPDATE_REFS_DIE_ON_ERR);
 }
	#include "cache.h"
	#include "refs.h"
	#include "builtin.h"
	#include "parse-options.h"
	#include "quote.h"
	#include "argv-array.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 int update_flags;
	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(struct strbuf input, 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_sha1(struct strbuf input, const char *next,
	unsigned char *sha1,
	const char command, const char refname,
	int flags)
	{
	struct strbuf arg = STRBUF_INIT;
	int ret = 0;

	if (*next == input->buf + input->len)
	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 (get_sha1(arg.buf, sha1))
	goto invalid;
	} else {
	/* Without -z, an empty value means all zeros: */
	hashclr(sha1);
	}
	} 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 == input->buf + input->len)
	goto eof;
	strbuf_addstr(&arg, *next);
	*next += arg.len;

	if (arg.len) {
	if (get_sha1(arg.buf, sha1))
	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);
	hashclr(sha1);
	} 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 const char parse_cmd_update(struct ref_transaction transaction,
	struct strbuf input, const char next)
	{
	struct strbuf err = STRBUF_INIT;
	char *refname;
	unsigned char new_sha1[20];
	unsigned char old_sha1[20];
	int have_old;

	refname = parse_refname(input, &next);
	if (!refname)
	die("update: missing <ref>");

	if (parse_next_sha1(input, &next, new_sha1, "update", refname,
	PARSE_SHA1_ALLOW_EMPTY))
	die("update %s: missing <newvalue>", refname);

	have_old = !parse_next_sha1(input, &next, old_sha1, "update", refname,
	PARSE_SHA1_OLD);

	if (*next != line_termination)
	die("update %s: extra input: %s", refname, next);

	if (ref_transaction_update(transaction, refname,
	new_sha1, have_old ? old_sha1 : NULL,
	update_flags, msg, &err))
	die("%s", err.buf);

	update_flags = 0;
	free(refname);
	strbuf_release(&err);

	return next;
	}

	static const char parse_cmd_create(struct ref_transaction transaction,
	struct strbuf input, const char next)
	{
	struct strbuf err = STRBUF_INIT;
	char *refname;
	unsigned char new_sha1[20];

	refname = parse_refname(input, &next);
	if (!refname)
	die("create: missing <ref>");

	if (parse_next_sha1(input, &next, new_sha1, "create", refname, 0))
	die("create %s: missing <newvalue>", refname);

	if (is_null_sha1(new_sha1))
	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_sha1,
	update_flags, msg, &err))
	die("%s", err.buf);

	update_flags = 0;
	free(refname);
	strbuf_release(&err);

	return next;
	}

	static const char parse_cmd_delete(struct ref_transaction transaction,
	struct strbuf input, const char next)
	{
	struct strbuf err = STRBUF_INIT;
	char *refname;
	unsigned char old_sha1[20];
	int have_old;

	refname = parse_refname(input, &next);
	if (!refname)
	die("delete: missing <ref>");

	if (parse_next_sha1(input, &next, old_sha1, "delete", refname,
	PARSE_SHA1_OLD)) {
	have_old = 0;
	} else {
	if (is_null_sha1(old_sha1))
	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_sha1 : NULL,
	update_flags, msg, &err))
	die("%s", err.buf);

	update_flags = 0;
	free(refname);
	strbuf_release(&err);

	return next;
	}

	static const char parse_cmd_verify(struct ref_transaction transaction,
	struct strbuf input, const char next)
	{
	struct strbuf err = STRBUF_INIT;
	char *refname;
	unsigned char old_sha1[20];

	refname = parse_refname(input, &next);
	if (!refname)
	die("verify: missing <ref>");

	if (parse_next_sha1(input, &next, old_sha1, "verify", refname,
	PARSE_SHA1_OLD))
	hashclr(old_sha1);

	if (*next != line_termination)
	die("verify %s: extra input: %s", refname, next);

	if (ref_transaction_verify(transaction, refname, old_sha1,
	update_flags, &err))
	die("%s", err.buf);

	update_flags = 0;
	free(refname);
	strbuf_release(&err);

	return next;
	}

	static const char parse_cmd_option(struct strbuf input, const char *next)
	{
	if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
	update_flags \|= REF_NODEREF;
	else
	die("option unknown: %s", next);
	return next + 8;
	}

	static void update_refs_stdin(struct ref_transaction *transaction)
	{
	struct strbuf input = STRBUF_INIT;
	const char *next;

	if (strbuf_read(&input, 0, 1000) < 0)
	die_errno("could not read from stdin");
	next = input.buf;
	/* Read each line dispatch its command */
	while (next < input.buf + input.len) {
	if (*next == line_termination)
	die("empty command in input");
	else if (isspace(*next))
	die("whitespace before command: %s", next);
	else if (starts_with(next, "update "))
	next = parse_cmd_update(transaction, &input, next + 7);
	else if (starts_with(next, "create "))
	next = parse_cmd_create(transaction, &input, next + 7);
	else if (starts_with(next, "delete "))
	next = parse_cmd_delete(transaction, &input, next + 7);
	else if (starts_with(next, "verify "))
	next = parse_cmd_verify(transaction, &input, next + 7);
	else if (starts_with(next, "option "))
	next = parse_cmd_option(&input, next + 7);
	else
	die("unknown command: %s", next);

	next++;
	}

	strbuf_release(&input);
	}

	int cmd_update_ref(int argc, const char *argv, const char prefix)
	{
	const char refname, oldval;
	unsigned char sha1[20], oldsha1[20];
	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
	unsigned int flags = 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_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.");

	if (read_stdin) {
	struct strbuf err = STRBUF_INIT;
	struct ref_transaction *transaction;

	transaction = ref_transaction_begin(&err);
	if (!transaction)
	die("%s", err.buf);
	if (delete \|\| no_deref \|\| argc > 0)
	usage_with_options(git_update_ref_usage, options);
	if (end_null)
	line_termination = '\0';
	update_refs_stdin(transaction);
	if (ref_transaction_commit(transaction, &err))
	die("%s", err.buf);
	ref_transaction_free(transaction);
	strbuf_release(&err);
	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 (get_sha1(value, sha1))
	die("%s: not a valid SHA1", value);
	}

	hashclr(oldsha1); /* all-zero hash in case oldval is the empty string */
	if (oldval && *oldval && get_sha1(oldval, oldsha1))
	die("%s: not a valid old SHA1", oldval);

	if (no_deref)
	flags = REF_NODEREF;
	if (delete)
	return delete_ref(refname, oldval ? oldsha1 : NULL, flags);
	else
	return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
	flags, UPDATE_REFS_DIE_ON_ERR);
	}