FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Thu, 08 Oct 2015 01:41:30 +0900] rev 26524
shelve: restore unshelved dirstate explicitly after aborting transaction
Before this patch, "hg unshelve" uses aborting a current transaction
to discard temporary changes while unshelving.
This assumes that dirstate changes in a transaction scope are kept
even after aborting it. But this assumption will be broken by
"transactional dirstate". See the wiki page below for detail about it.
https://mercurial.selenic.com/wiki/DirstateTransactionPlan
This patch explicitly saves shelved dirstate just before aborting
current transaction, and restore dirstate with it after aborting by
utility function '_aborttransaction()' added by previous patch.
FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Thu, 08 Oct 2015 01:41:30 +0900] rev 26523
shelve: restore shelved dirstate explicitly after aborting transaction
Before this patch, "hg shelve" uses aborting a current transaction to
discard temporary changes while shelving.
This assumes that dirstate changes in a transaction scope are kept
even after aborting it. But this assumption will be broken by
"transactional dirstate". See the wiki page below for detail about it.
https://mercurial.selenic.com/wiki/DirstateTransactionPlan
This patch explicitly saves shelved dirstate just before aborting
current transaction, and restore dirstate with it after aborting by
utility function '_aborttransaction()' added by previous patch.
This patch replaces 'if tr: tr.abort()' by 'lockmod.release(tr)',
because the former is already done in '_aborttransaction()' (and the
latter has no effect), if current transaction is aborted in it
successfully. Otherwise, the latter is enough to trigger aborting.
FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Thu, 08 Oct 2015 01:41:30 +0900] rev 26522
shelve: add utility to abort current transaction but keep dirstate
"hg shelve" and "hg unshelve" use aborting a current transaction to
discard temporary changes while (un)shelving.
This assumes that dirstate changes in a transaction scope are kept
even after aborting it. But this assumption will be broken by
"transactional dirstate". See the wiki page below for detail about it.
https://mercurial.selenic.com/wiki/DirstateTransactionPlan
This patch adds utility function "_aborttransaction()" to abort
current transaction but keep dirstate changes for (un)shelving.
'dirstate.invalidate()' just after aborting a transaction should be
removed soon by subsequent patch, which writes or discards in-memory
dirstate changes at releasing transaction according to the result of
it.
BTW, there are some other ways below, which (seem to, at first glance)
resolve this issue. But this patch chose straightforward way for ease
of review and future refactorring.
- commit transaction at first, and then rollback it
It causes unintentional "dirty read" of running transaction to
other processes at committing it.
- use dirstateguard to save and restore shelved dirstate
After DirstateTransactionPlan, making 'dirstate.write()' write
in-memory changes into actual file requires
'transaction.writepending()' while transaction running.
It causes meaningless writing other in-memory changes out, even
though they are never referred.
In addition to it, it isn't desirable that scope of dirstateguard
and transaction intersects each other.
- get list of files changed from the parent, keep it in memory, and
emulate that changes after aborting transaction
This additional memory consumption may block aborting transaction
in large repository (on small resource environment).