transaction: pass the transaction to 'pending' callback The callback will likely need to perform some operation related to the transaction (eg: backing files up). So we better pass the current transaction as the callback argument. Otherwise callback that needs it has to rely on horrible weak reference trick. The first foreseen user of this is changelog._writepending. We would like it to register the temporary file it create for cleanup purpose.

transaction: gather backupjournal logic together in the __init__ The initialisation of file-backup related variable were a bit scattered, we gather them together.

transaction: handle missing file in backupentries (instead of using entries) The case where a backup of a missing file was requested was previously handled by the 'entries' list. As the 'backupentries' is about to gain ability to backup files outside of '.hg/store', we want it to be able to handle the missing file too. Reminder: using 'addbackup' on a missing file means that such file needs to be deleted if we rollback the transaction.

test-hup: use ls instead of echo Having one file entry per line makes it easier to analyse diffs.