1 files changed, 89 insertions, 8 deletions

diff --git a/refs.c b/refs.c
index a5851a7de0..f4094a326a 100644
--- a/refs.c
+++ b/refs.c
@@ -3,6 +3,7 @@
  */
 
 #define USE_THE_REPOSITORY_VARIABLE
+#define DISABLE_SIGN_COMPARE_WARNINGS
 
 #include "git-compat-util.h"
 #include "advice.h"
@@ -699,6 +700,53 @@ static char *substitute_branch_name(struct repository *r,
 	return NULL;
 }
 
+void copy_branchname(struct strbuf *sb, const char *name, unsigned allowed)
+{
+	int len = strlen(name);
+	struct interpret_branch_name_options options = {
+		.allowed = allowed
+	};
+	int used = repo_interpret_branch_name(the_repository, name, len, sb,
+					      &options);
+
+	if (used < 0)
+		used = 0;
+	strbuf_add(sb, name + used, len - used);
+}
+
+int check_branch_ref(struct strbuf *sb, const char *name)
+{
+	if (startup_info->have_repository)
+		copy_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
+	else
+		strbuf_addstr(sb, name);
+
+	/*
+	 * This splice must be done even if we end up rejecting the
+	 * name; builtin/branch.c::copy_or_rename_branch() still wants
+	 * to see what the name expanded to so that "branch -m" can be
+	 * used as a tool to correct earlier mistakes.
+	 */
+	strbuf_splice(sb, 0, 0, "refs/heads/", 11);
+
+	if (*name == '-' ||
+	    !strcmp(sb->buf, "refs/heads/HEAD"))
+		return -1;
+
+	return check_refname_format(sb->buf, 0);
+}
+
+int check_tag_ref(struct strbuf *sb, const char *name)
+{
+	if (name[0] == '-' || !strcmp(name, "HEAD"))
+		return -1;
+
+	strbuf_reset(sb);
+	strbuf_addf(sb, "refs/tags/%s", name);
+
+	return check_refname_format(sb->buf, 0);
+}
+
 int repo_dwim_ref(struct repository *r, const char *str, int len,
 		  struct object_id *oid, char **ref, int nonfatal_dangling_mark)
 {
@@ -1282,7 +1330,7 @@ int ref_transaction_update_reflog(struct ref_transaction *transaction,
 
 	assert(err);
 
-	flags |= REF_LOG_ONLY | REF_NO_DEREF;
+	flags |= REF_LOG_ONLY | REF_FORCE_CREATE_REFLOG | REF_NO_DEREF;
 
 	if (!transaction_refname_valid(refname, new_oid, flags, err))
 		return -1;
@@ -2180,19 +2228,53 @@ int peel_iterated_oid(struct repository *r, const struct object_id *base, struct
 int refs_update_symref(struct ref_store *refs, const char *ref,
 		       const char *target, const char *logmsg)
 {
+	return refs_update_symref_extended(refs, ref, target, logmsg, NULL, 0);
+}
+
+int refs_update_symref_extended(struct ref_store *refs, const char *ref,
+		       const char *target, const char *logmsg,
+		       struct strbuf *referent, int create_only)
+{
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
-	int ret = 0;
+	int ret = 0, prepret = 0;
 
 	transaction = ref_store_transaction_begin(refs, 0, &err);
-	if (!transaction ||
-	    ref_transaction_update(transaction, ref, NULL, NULL,
-				   target, NULL, REF_NO_DEREF,
-				   logmsg, &err) ||
-	    ref_transaction_commit(transaction, &err)) {
+	if (!transaction) {
+	error_return:
 		ret = error("%s", err.buf);
+		goto cleanup;
+	}
+	if (create_only) {
+		if (ref_transaction_create(transaction, ref, NULL, target,
+					   REF_NO_DEREF, logmsg, &err))
+			goto error_return;
+		prepret = ref_transaction_prepare(transaction, &err);
+		if (prepret && prepret != TRANSACTION_CREATE_EXISTS)
+			goto error_return;
+	} else {
+		if (ref_transaction_update(transaction, ref, NULL, NULL,
+					   target, NULL, REF_NO_DEREF,
+					   logmsg, &err) ||
+			ref_transaction_prepare(transaction, &err))
+			goto error_return;
+	}
+
+	if (referent && refs_read_symbolic_ref(refs, ref, referent) == NOT_A_SYMREF) {
+		struct object_id oid;
+		if (!refs_read_ref(refs, ref, &oid)) {
+			strbuf_addstr(referent, oid_to_hex(&oid));
+			ret = NOT_A_SYMREF;
+		}
 	}
 
+	if (prepret == TRANSACTION_CREATE_EXISTS)
+		goto cleanup;
+
+	if (ref_transaction_commit(transaction, &err))
+		goto error_return;
+
+cleanup:
 	strbuf_release(&err);
 	if (transaction)
 		ref_transaction_free(transaction);
@@ -3041,4 +3123,3 @@ int ref_update_expects_existing_old_ref(struct ref_update *update)
 	return (update->flags & REF_HAVE_OLD) &&
 		(!is_null_oid(&update->old_oid) || update->old_target);
 }
-