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>

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 85e1e1c759d37eaa2bf3f2ce8fafc48ac280867a..2f98eebe94e1a7ca42b2999eeb3868e2b7096a39 100644 (file)
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2683,7 +2683,7 @@ static int commit_ref_update(struct ref_lock *lock,
                        }
                }
        }
-       if (commit_ref(lock)) {
+       if (!(flags & REF_LOG_ONLY) && commit_ref(lock)) {
                strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
                unlock_ref(lock);
                return -1;
@@ -3101,7 +3101,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                        goto cleanup;
                }
                if ((update->flags & REF_HAVE_NEW) &&
-                   !(update->flags & REF_DELETING)) {
+                   !(update->flags & REF_DELETING) &&
+                   !(update->flags & REF_LOG_ONLY)) {
                        int overwriting_symref = ((update->type & REF_ISSYMREF) &&
                                                  (update->flags & REF_NODEREF));
 
@@ -3133,8 +3134,9 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                }
                if (!(update->flags & REF_NEEDS_COMMIT)) {
                        /*
-                        * We didn't have to write anything to the lockfile.
-                        * Close it to free up the file descriptor:
+                        * We didn't call write_ref_to_lockfile(), so
+                        * the lockfile is still open. Close it to
+                        * free up the file descriptor:
                         */
                        if (close_ref(update->lock)) {
                                strbuf_addf(err, "couldn't close '%s.lock'",
@@ -3149,7 +3151,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
 
-               if (update->flags & REF_NEEDS_COMMIT) {
+               if (update->flags & REF_NEEDS_COMMIT ||
+                   update->flags & REF_LOG_ONLY) {
                        if (commit_ref_update(update->lock,
                                              update->new_sha1, update->msg,
                                              update->flags, err)) {
@@ -3168,7 +3171,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
 
-               if (update->flags & REF_DELETING) {
+               if (update->flags & REF_DELETING &&
+                   !(update->flags & REF_LOG_ONLY)) {
                        if (delete_ref_loose(update->lock, update->type, err)) {
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;

diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 1f94f7a262216f0f177a262a80c4db57903d6551..85f4650ab872a0da3e8fb367f781c72fe5515bcc 100644 (file)
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -42,6 +42,13 @@
  * value to ref_update::flags
  */
 
+/*
+ * Used as a flag in ref_update::flags when we want to log a ref
+ * update but not actually perform it.  This is used when a symbolic
+ * ref update is split up.
+ */
+#define REF_LOG_ONLY 0x80
+
 /*
  * Return true iff refname is minimally safe. "Safe" here means that
  * deleting a loose reference by this name will not do any damage, for