transaction: use the standard transaction mechanism to backup branch Branch is a bit special : - It currently does not collaborate with the transaction (or any scoping) for writing (this is bad) - It can change without the lock being taken (it is protected by `wlock`) So we rely on the same mechanism as for the backup of the other dirstate file: - we only do a backup if we hold the wlock - we force a backup though the transaction Since "branch" write does not collaborate with the transaction, we cannot back it up "at the last minute" as we do for the dirstate. We have to back it up "upfront". Since we have a backup, the transaction is no longer doing its "quick_abort" and get noisy. Which is quite annoying. To work around this, and to avoid jumping in yet-another-rabbit-hole of "getting branch written properly", I am doing horrible things to the transaction in the meantime. We should be able to get this code go away during the next cycle. In the meantime, I prefer to take this small stop so that we stop abusing the "journal" and "undo" mechanism instead of the proper backup mechanism of the transaction. Also note that this change regress the warning message for the legacy fallback introduced in 2008 when issue902 got fixed in dd5a501cb97f (Mercurial 1.0). I feel like this is fine as issue 902 remains fixed, and this would only affect people deploying a mix of 15 year old Mercurial and modern mercurial, and using branch and rollback extensively.

transaction: no longer explicitly cache bookmarks The transaction file generation is already dealing with the backup for this. So, no need to duplicate such backup.

transaction: no longer explicitly cache phaseroots The transaction file generation is already dealing with the backup for this. So, no need to duplicate such backup.

narrow: enforce that narrow spec is written within a transaction

narrow: write the narrow spec in a transaction during share It will be simpler if all write happens within transaction.

narrow: open the transaction sooner when unbundling That way, the narrow spec changes will be done within a transaction.

narrow: write the narrow spec in a transaction during clone It will be simpler if all write happens within transaction.

narrow: drop the dedicated backup code Now that the transaction manage the writes, we can simply use the transaction for backup. Some extra cleanup to ensure all changes happens within a transaction will be made in the next changesets.

narrow: delegate the dirstate's narrow spec writing to the transaction This make it more transactional and will help us to simplify their backup. The implementation is not great, but it keep the patch simple as this is not the time for a larger refactoring yet.

narrow: delegate the narrow spec writing to the transaction This make it more transactional and will help us to simplify their backup. The implementation is not great, but it keep the patch simple as this is not the time for a larger refactoring yet.