1 files changed, 40 insertions, 19 deletions

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 1993529521..7f30d3a76f 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -6,14 +6,15 @@
 #include "argv-array.h"
 
 static const char * const git_update_ref_usage[] = {
-	N_("git update-ref [options] -d <refname> [<oldval>]"),
-	N_("git update-ref [options]    <refname> <newval> [<oldval>]"),
-	N_("git update-ref [options] --stdin [-z]"),
+	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 unsigned create_reflog_flag;
 static const char *msg;
 
 /*
@@ -198,8 +199,10 @@ static const char *parse_cmd_update(struct ref_transaction *transaction,
 	if (*next != line_termination)
 		die("update %s: extra input: %s", refname, next);
 
-	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-				   update_flags, have_old, msg, &err))
+	if (ref_transaction_update(transaction, refname,
+				   new_sha1, have_old ? old_sha1 : NULL,
+				   update_flags | create_reflog_flag,
+				   msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -230,7 +233,8 @@ static const char *parse_cmd_create(struct ref_transaction *transaction,
 		die("create %s: extra input: %s", refname, next);
 
 	if (ref_transaction_create(transaction, refname, new_sha1,
-				   update_flags, msg, &err))
+				   update_flags | create_reflog_flag,
+				   msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -264,8 +268,9 @@ static const char *parse_cmd_delete(struct ref_transaction *transaction,
 	if (*next != line_termination)
 		die("delete %s: extra input: %s", refname, next);
 
-	if (ref_transaction_delete(transaction, refname, old_sha1,
-				   update_flags, have_old, msg, &err))
+	if (ref_transaction_delete(transaction, refname,
+				   have_old ? old_sha1 : NULL,
+				   update_flags, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -280,7 +285,6 @@ static const char *parse_cmd_verify(struct ref_transaction *transaction,
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
-	unsigned char new_sha1[20];
 	unsigned char old_sha1[20];
 
 	refname = parse_refname(input, &next);
@@ -291,13 +295,11 @@ static const char *parse_cmd_verify(struct ref_transaction *transaction,
 			    PARSE_SHA1_OLD))
 		hashclr(old_sha1);
 
-	hashcpy(new_sha1, old_sha1);
-
 	if (*next != line_termination)
 		die("verify %s: extra input: %s", refname, next);
 
-	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-				   update_flags, 1, msg, &err))
+	if (ref_transaction_verify(transaction, refname, old_sha1,
+				   update_flags, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -353,7 +355,9 @@ 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, flags = 0;
+	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
+	unsigned int flags = 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")),
@@ -361,6 +365,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 					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(),
 	};
 
@@ -370,6 +375,8 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 	if (msg && !*msg)
 		die("Refusing to perform update with empty message.");
 
+	create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
+
 	if (read_stdin) {
 		struct strbuf err = STRBUF_INIT;
 		struct ref_transaction *transaction;
@@ -408,15 +415,29 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 			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 (oldval) {
+		if (!*oldval)
+			/*
+			 * The empty string implies that the reference
+			 * must not already exist:
+			 */
+			hashclr(oldsha1);
+		else if (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);
+		/*
+		 * For purposes of backwards compatibility, we treat
+		 * NULL_SHA1 as "don't care" here:
+		 */
+		return delete_ref(refname,
+				  (oldval && !is_null_sha1(oldsha1)) ? oldsha1 : NULL,
+				  flags);
 	else
 		return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
-				  flags, UPDATE_REFS_DIE_ON_ERR);
+				  flags | create_reflog_flag,
+				  UPDATE_REFS_DIE_ON_ERR);
 }