filemerge: move 'merging' output to before file creation This has no visible impact but makes some future work simpler.

filemerge.filemerge: make a tuple containing merge paths on disk We're going to need this same tuple elsewhere.

filemerge: switch trymerge boolean to mergetype enum trymerge = False becomes mergetype = nomerge, and trymerge = True becomes mergetype = fullmerge or mergeonly, depending on whether a premerge happens.

filemerge: add some merge types We're going to turn the 'trymerge' boolean into a 'mergetype' enum with these three possible values.

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.

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.

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).

dirstate: split write to write changes into files other than .hg/dirstate '_writedirstate()' is used mainly for "transactional dirstate". See the wiki page below for detail about it. https://mercurial.selenic.com/wiki/DirstateTransactionPlan

bookmarks: use recordchange instead of writing if transaction is active Before this patch, 'bmstore.write()' always write in-memory bookmark changes into '.hg/bookmarks' regardless of transaction activity. If 'bmstore.write()' is invoked inside a transaction and it writes changes into '.hg/bookmarks', then: - original bookmarks aren't restored at failure of that transaction This breaks "all or nothing" policy of the transaction. BTW, "hg rollback" can restore bookmarks successfully even before this patch, because original bookmarks are saved into '.hg/journal.bookmarks' at the beginning of the transaction, and it (actually renamed as '.hg/undo.bookmarks') is used by "hg rollback". - uncommitted bookmark changes are visible to other processes This is a kind of "dirty read" For example, 'rebase.rebase()' implies 'bmstore.write()', and it may be executed inside the transaction of "hg unshelve". Then, intentional aborting at the end of "hg unshelve" transaction doesn't restore original bookmarks (this is obviously a bug). This patch uses 'bmstore.recordchange()' instead of actual writing by 'bmstore._writerepo()', if any transaction is active This patch also removes meaningless restoring bmstore explicitly at the end of "hg shelve". This patch doesn't choose fixing each 'bmstore.write()' callers as like below, because writing similar code here and there is very redundant. before: bmstore.write() after: tr = repo.currenttransaction() if tr: bmstore.recordchange(tr) else: bmstore.write() Even though 'bmstore.write()' itself may have to be discarded by putting bookmark operations into transaction scope, this patch chose fixing it to implement "transactional dirstate" at first.

filemerge: run symlink check for :merge3 Just like :merge, :merge3 doesn't support merging symlinks.