-- Copyright (C) 2002-2004,2007-2008 David Roundy -- Copyright (C) 2005 Juliusz Chroboczek -- Copyright (C) 2009 Petr Rockai -- -- This program is free software; you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation; either version 2, or (at your option) -- any later version. -- -- This program is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with this program; see the file COPYING. If not, write to -- the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, -- Boston, MA 02110-1301, USA. module Darcs.Repository.Merge ( tentativelyMergePatches , considerMergeToWorking ) where import Darcs.Prelude import Control.Monad ( when, unless ) import System.Exit ( exitSuccess ) import System.IO.Error ( catchIOError , ioeGetErrorType , isIllegalOperationErrorType ) import Darcs.Util.Tree( Tree ) import Darcs.Util.File ( backupByCopying ) import Darcs.Patch ( RepoPatch, PrimOf, merge , effect , listConflictedFiles ) import Darcs.Patch.Apply ( ApplyState ) import Darcs.Patch.Depends ( slightlyOptimizePatchset ) import Darcs.Patch.Invertible ( mkInvertible ) import Darcs.Patch.Named ( patchcontents, anonymous ) import Darcs.Patch.PatchInfoAnd ( PatchInfoAnd, n2pia, hopefully ) import Darcs.Patch.Progress( progressFL, progressRL ) import Darcs.Patch.Set ( PatchSet, Origin, appendPSFL, patchSet2RL ) import Darcs.Patch.Witnesses.Ordered ( FL(..), RL(..), Fork(..), (:\/:)(..), (:/\:)(..), (+>+), (+<<+) , lengthFL, mapFL_FL, concatFL, reverseFL ) import Darcs.Patch.Witnesses.Sealed ( Sealed(Sealed), seal ) import Darcs.Repository.Flags ( DiffOpts (..) , AllowConflicts (..) , ResolveConflicts (..) , Reorder (..) , UpdatePending (..) , WantGuiPause (..) ) import Darcs.Repository.Hashed ( tentativelyAddPatches_ , tentativelyRemovePatches_ , UpdatePristine(..) ) import Darcs.Repository.Pristine ( applyToTentativePristine ) import Darcs.Repository.InternalTypes ( AccessType(RW), Repository, repoLocation ) import Darcs.Repository.Pending ( setTentativePending ) import Darcs.Repository.Resolution ( StandardResolution(..) , announceConflicts , externalResolution , patchsetConflictResolutions , standardResolution ) import Darcs.Repository.State ( unrecordedChanges, readUnrecorded ) import Darcs.Util.Prompt ( promptYorn ) import Darcs.Util.Path ( anchorPath, displayPath ) import Darcs.Util.Progress( debugMessage ) import Darcs.Util.Printer.Color ( ePutDocLn ) import Darcs.Util.Printer ( redText, vcat ) data MakeChanges = MakeChanges | DontMakeChanges deriving ( Eq ) {- 'tentativelyMergePatches' is not easy to understand by just staring at the code. So here is an in-depth explanation. We start out at the state X at which our repo and the their repo deviate, assuming any patches common to both repos have first been commuted to the common part before X. So X is the intermediate state that is existentially hiddden inside the Fork we get passed as argument. R is our recorded state and Y is the recorded state of their repo. Y R \ / them us \ / X | common | O We will elide the common part from now on. It doesn't change and we only pass it unmodified to standardResolution, see below. The easy part is to merge the local patches (us) with the remote ones (them), giving us them' and us'. T / \ us' them' / \ Y R \ / them us \ / X We can ignore us' and just add them' on top of us (which are already in our repo), unless --reorder-patches is in effect, in which case we remove us and then first add them and afterwards us'. The new state on top is T which stands for the new /tentative/ state i.e. what will become the recorded state after we finalize our changes. But we're not done yet: we must also adapt the pending patch and the working tree. Note that changing the working tree is not done in this procedure, we merely return a list of prims to apply to working. Let us add the difference between pristine and working, which we call pw, to the picture. T U / \ / us' them' pw / \ / Y R \ / them us \ / X It is easy to see now that we must merge pw with them', as both start at the (old) recorded state. This gives us pw' and them''. U' / \ pw' them'' / \ T U / \ / us' them' pw / \ / Y R \ / them us \ / X Since U is our unrecorded state, them'' leads us from our old unrecorded state to the new one, so this is what we will return (if there are no conflicts; if there are, see below). What about the pending patch? It starts at R and goes half-way toward U since it is a prefix of pw. The new pending should start at T and go half-way toward the new working state U'. Instead of adapting the old pending patch, we set the new pending patch to pw', ignoring the old one. This relies on sifting to commute out and drop the parts that need not be in the pending patch, which is done when we finalize the tentative changes. Up to now we did not consider conflicts. Any new conflicts arising from the merges we made so far must be "resolved", that is, marked for manual resolution, if possible, or at least reported to the user. We made two merges, one with us and one with pw. It is important now to realize that our existing repo, and in particular the sequence us, could already be conflicted. Our job is to resolve only /new/ conflicts and not any unresolved conflicts that were already in our repo. So, from the rightmost branch of our double merge us+>+pw+>+them'', we should /not/ resolve us. And since the original pw cannot be conflicted (it consists of prim patches only) we can disregard it. This leaves only them'' which is what we pass to standardResolution to generate the markup, along with its full context, consisting of (common +>+ us +>+ pw). The resulting "resolution" goes on top, leading to our final unrecorded state U'': U'' | res | U' / \ pw' them'' / \ T U / \ / us' them' pw / \ / Y R \ / them us \ / X In case the patches we pull are in conflict with local /unrecorded/ changes (i.e. pw), we want to warn the user about that and allow them to cancel the operation. The reason is that it is hard to reconstruct the original unrecorded changes when they are messed up with conflict resolution markup. To see if this is the case we check whether pw' has conflicts. As an extra precaution we backup any conflicted files, so the user can refer to them to restore things or compare in a diff viewer. The patches we return are what we need to update U to U'' i.e. them''+>+res. The new pending patch starts out at the new tentative state, so as explained above, we set it to pw'+>+res, and again rely on sifting to commute out and drop anything we don't need. TODO: We should return a properly coerced @Repository 'RW p wU wR@. -} tentativelyMergePatches_ :: (RepoPatch p, ApplyState p ~ Tree) => MakeChanges -> Repository 'RW p wU wR -> String -> AllowConflicts -> WantGuiPause -> Reorder -> DiffOpts -> Fork (PatchSet p) (FL (PatchInfoAnd p)) (FL (PatchInfoAnd p)) Origin wR wY -> IO (Sealed (FL (PrimOf p) wU)) tentativelyMergePatches_ mc _repo cmd allowConflicts wantGuiPause reorder diffingOpts@DiffOpts{..} (Fork context us them) = do (them' :/\: us') <- return $ merge (progressFL "Merging us" us :\/: progressFL "Merging them" them) pw <- unrecordedChanges diffingOpts _repo Nothing -- Note: we use anonymous here to wrap the unrecorded changes. -- This is benign because we only retain the effect of the results -- of the merge (pw' and them''). anonpw <- n2pia `fmap` anonymous pw pw' :/\: them'' <- return $ merge (them' :\/: anonpw :>: NilFL) let them''content = concatFL $ mapFL_FL (patchcontents . hopefully) them'' no_conflicts_in_them = null $ conflictedPaths $ patchsetConflictResolutions $ slightlyOptimizePatchset (appendPSFL context them) conflicts = let us'' = us' +>+ pw' in -- This optimization is valid only if @them@ didn't have -- (unresolved) conflicts in the first place if lengthFL us'' < lengthFL them'' && no_conflicts_in_them then standardResolution (patchSet2RL context +<<+ them) (progressRL "Examining patches for conflicts" $ reverseFL us'') else standardResolution (patchSet2RL context +<<+ us :<: anonpw) (progressRL "Examining patches for conflicts" $ reverseFL them'') debugMessage "Checking for conflicts..." when (allowConflicts == YesAllowConflicts MarkConflicts) $ mapM_ backupByCopying $ map (anchorPath (repoLocation _repo)) $ conflictedPaths conflicts debugMessage "Announcing conflicts..." have_conflicts <- announceConflicts cmd allowConflicts conflicts debugMessage "Checking for unrecorded conflicts..." let pw'content = concatFL $ mapFL_FL (patchcontents . hopefully) pw' case listConflictedFiles pw'content of [] -> return () fs -> do ePutDocLn $ vcat $ map redText $ "You have conflicting unrecorded changes to:" : map displayPath fs -- we catch "hIsTerminalDevice: illegal operation (handle is closed)" -- which can be thrown when we apply patches remotely (i.e. during push) confirmed <- promptYorn "Proceed?" `catchIOError` (\e -> if isIllegalOperationErrorType (ioeGetErrorType e) then return True else ioError e) unless confirmed $ do putStrLn "Cancelled." exitSuccess debugMessage "Reading working tree..." working <- readUnrecorded _repo withIndex Nothing debugMessage "Working out conflict markup..." Sealed resolution <- if have_conflicts then case allowConflicts of YesAllowConflicts (ExternalMerge merge_cmd) -> externalResolution diffAlg working merge_cmd wantGuiPause (effect us +>+ pw) (effect them) them''content YesAllowConflicts NoResolveConflicts -> return $ seal NilFL YesAllowConflicts MarkConflicts -> return $ mangled conflicts NoAllowConflicts -> error "impossible" -- was handled in announceConflicts else return $ seal NilFL debugMessage "Adding patches to the inventory and writing new pending..." when (mc == MakeChanges) $ do applyToTentativePristine _repo $ mkInvertible $ progressFL "Applying patches to pristine" them' -- these two cases result in the same trees (that's the idea of -- merging), so we only operate on the set of patches and do the -- adaption of pristine and pending in the common code below _repo <- case reorder of NoReorder -> do tentativelyAddPatches_ DontUpdatePristine _repo NoUpdatePending them' Reorder -> do -- we do not actually remove any effect in the end, so -- it would be wrong to update the unrevert bundle or -- the working tree or pending _repo <- tentativelyRemovePatches_ DontUpdatePristineNorRevert _repo NoUpdatePending us _repo <- tentativelyAddPatches_ DontUpdatePristine _repo NoUpdatePending them tentativelyAddPatches_ DontUpdatePristine _repo NoUpdatePending us' setTentativePending _repo (effect pw' +>+ resolution) return $ seal (effect them''content +>+ resolution) tentativelyMergePatches :: (RepoPatch p, ApplyState p ~ Tree) => Repository 'RW p wU wR -> String -> AllowConflicts -> WantGuiPause -> Reorder -> DiffOpts -> Fork (PatchSet p) (FL (PatchInfoAnd p)) (FL (PatchInfoAnd p)) Origin wR wY -> IO (Sealed (FL (PrimOf p) wU)) tentativelyMergePatches = tentativelyMergePatches_ MakeChanges considerMergeToWorking :: (RepoPatch p, ApplyState p ~ Tree) => Repository 'RW p wU wR -> String -> AllowConflicts -> WantGuiPause -> Reorder -> DiffOpts -> Fork (PatchSet p) (FL (PatchInfoAnd p)) (FL (PatchInfoAnd p)) Origin wR wY -> IO (Sealed (FL (PrimOf p) wU)) considerMergeToWorking = tentativelyMergePatches_ DontMakeChanges