refs: allow log-only updates

The refs infrastructure learns about log-only ref updates, which only update the reflog. Later, we will use this to separate symbolic reference resolution from ref updating. Signed-off-by: David Turner <dturner@twopensource.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>

David Turner committed Feb 24, 2016 at 17:58 UTC d99aa884dff33d48d5aab8c9cf989a25c779fd70
2 files changed +17 -6
refs/files-backend.c
+10 -6
@@ -2683,7 +2683,7 @@ static int commit_ref_update(struct ref_lock *lock,
2683 }
2684 }
2685 }
2686 - if (commit_ref(lock)) {
2686 + if (!(flags & REF_LOG_ONLY) && commit_ref(lock)) {
2687 strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
2688 unlock_ref(lock);
2689 return -1;
@@ -3101,7 +3101,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
3101 goto cleanup;
3102 }
3103 if ((update->flags & REF_HAVE_NEW) &&
3104 - !(update->flags & REF_DELETING)) {
3104 + !(update->flags & REF_DELETING) &&
3105 + !(update->flags & REF_LOG_ONLY)) {
3106 int overwriting_symref = ((update->type & REF_ISSYMREF) &&
3107 (update->flags & REF_NODEREF));
3108
@@ -3133,8 +3134,9 @@ int ref_transaction_commit(struct ref_transaction *transaction,
3134 }
3135 if (!(update->flags & REF_NEEDS_COMMIT)) {
3136 /*
3136 - * We didn't have to write anything to the lockfile.
3137 - * Close it to free up the file descriptor:
3137 + * We didn't call write_ref_to_lockfile(), so
3138 + * the lockfile is still open. Close it to
3139 + * free up the file descriptor:
3140 */
3141 if (close_ref(update->lock)) {
3142 strbuf_addf(err, "couldn't close '%s.lock'",
@@ -3149,7 +3151,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
3151 for (i = 0; i < transaction->nr; i++) {
3152 struct ref_update *update = transaction->updates[i];
3153
3152 - if (update->flags & REF_NEEDS_COMMIT) {
3154 + if (update->flags & REF_NEEDS_COMMIT ||
3155 + update->flags & REF_LOG_ONLY) {
3156 if (commit_ref_update(update->lock,
3157 update->new_sha1, update->msg,
3158 update->flags, err)) {
@@ -3168,7 +3171,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
3171 for (i = 0; i < transaction->nr; i++) {
3172 struct ref_update *update = transaction->updates[i];
3173
3171 - if (update->flags & REF_DELETING) {
3174 + if (update->flags & REF_DELETING &&
3175 + !(update->flags & REF_LOG_ONLY)) {
3176 if (delete_ref_loose(update->lock, update->type, err)) {
3177 ret = TRANSACTION_GENERIC_ERROR;
3178 goto cleanup;
refs/refs-internal.h
+7
@@ -42,6 +42,13 @@
42 * value to ref_update::flags
43 */
44
45 +/*
46 + * Used as a flag in ref_update::flags when we want to log a ref
47 + * update but not actually perform it. This is used when a symbolic
48 + * ref update is split up.
49 + */
50 +#define REF_LOG_ONLY 0x80
51 +
52 /*
53 * Return true iff refname is minimally safe. "Safe" here means that
54 * deleting a loose reference by this name will not do any damage, for