diff options
| -rw-r--r-- | Annex/Branch.hs | 1 | ||||
| -rw-r--r-- | Command/Export.hs | 4 | ||||
| -rw-r--r-- | Git/Tree.hs | 6 | ||||
| -rw-r--r-- | Logs/Export.hs | 24 | ||||
| -rw-r--r-- | doc/design/exporting_trees_to_special_remotes.mdwn | 15 |
5 files changed, 35 insertions, 15 deletions
diff --git a/Annex/Branch.hs b/Annex/Branch.hs index 5482dc44b..5214df627 100644 --- a/Annex/Branch.hs +++ b/Annex/Branch.hs @@ -21,6 +21,7 @@ module Annex.Branch ( maybeChange, commit, forceCommit, + getBranch, files, withIndex, performTransitions, diff --git a/Command/Export.hs b/Command/Export.hs index 1310244ac..0df13e489 100644 --- a/Command/Export.hs +++ b/Command/Export.hs @@ -70,7 +70,9 @@ seek :: ExportOptions -> CommandSeek seek o = do r <- getParsed (exportRemote o) new <- fromMaybe (error "unknown tree") <$> - inRepo (Git.Ref.sha (exportTreeish o)) + -- Dereference the tree pointed to by the branch, commit, + -- or tag. + inRepo (Git.Ref.tree (exportTreeish o)) old <- getExport (uuid r) when (length old > 1) $ diff --git a/Git/Tree.hs b/Git/Tree.hs index 3e6b85a1d..9e9b17af2 100644 --- a/Git/Tree.hs +++ b/Git/Tree.hs @@ -14,6 +14,7 @@ module Git.Tree ( recordTree, TreeItem(..), adjustTree, + treeMode, ) where import Common @@ -94,12 +95,15 @@ mkTree (MkTreeHandle cp) l = CoProcess.query cp send receive send h = do forM_ l $ \i -> hPutStr h $ case i of TreeBlob f fm s -> mkTreeOutput fm BlobObject s f - RecordedSubTree f s _ -> mkTreeOutput 0o040000 TreeObject s f + RecordedSubTree f s _ -> mkTreeOutput treeMode TreeObject s f NewSubTree _ _ -> error "recordSubTree internal error; unexpected NewSubTree" TreeCommit f fm s -> mkTreeOutput fm CommitObject s f hPutStr h "\NUL" -- signal end of tree to --batch receive h = getSha "mktree" (hGetLine h) +treeMode :: FileMode +treeMode = 0o040000 + mkTreeOutput :: FileMode -> ObjectType -> Sha -> TopFilePath -> String mkTreeOutput fm ot s f = concat [ showOct fm "" diff --git a/Logs/Export.hs b/Logs/Export.hs index a0019a06c..1fd1460fc 100644 --- a/Logs/Export.hs +++ b/Logs/Export.hs @@ -12,6 +12,9 @@ import qualified Data.Map as M import Annex.Common import qualified Annex.Branch import qualified Git +import qualified Git.Branch +import Git.Tree +import Git.FilePath import Logs import Logs.UUIDBased import Annex.UUID @@ -40,6 +43,9 @@ data ExportChange = ExportChange -- newTreeish. This way, when multiple repositories are exporting to -- the same special remote, there's no conflict as long as they move -- forward in lock-step. +-- +-- Also, the newTreeish is grafted into the git-annex branch. This is done +-- to ensure that it's available later. recordExport :: UUID -> ExportChange -> Annex () recordExport remoteuuid ec = do c <- liftIO currentVectorClock @@ -50,6 +56,7 @@ recordExport remoteuuid ec = do . changeLog c u val . M.mapWithKey (updateothers c u) . parseLogNew parseExportLog + graftTreeish (newTreeish ec) where updateothers c u theiru le@(LogEntry _ (ExportLog t remoteuuid')) | u == theiru || remoteuuid' /= remoteuuid || t `notElem` oldTreeish ec = le @@ -65,3 +72,20 @@ parseExportLog :: String -> Maybe ExportLog parseExportLog s = case words s of (t:u:[]) -> Just $ ExportLog (Git.Ref t) (toUUID u) _ -> Nothing + +-- To prevent git-annex branch merge conflicts, the treeish is +-- first grafted in and then removed in a subsequent commit. +graftTreeish :: Git.Ref -> Annex () +graftTreeish treeish = do + branchref <- Annex.Branch.getBranch + Tree t <- inRepo $ getTree branchref + t' <- inRepo $ recordTree $ Tree $ + RecordedSubTree (asTopFilePath graftpoint) treeish [] : t + commit <- inRepo $ Git.Branch.commitTree Git.Branch.AutomaticCommit + "export tree" [branchref] t' + origtree <- inRepo $ recordTree (Tree t) + commit' <- inRepo $ Git.Branch.commitTree Git.Branch.AutomaticCommit + "export tree cleanup" [commit] origtree + inRepo $ Git.Branch.update' Annex.Branch.fullname commit' + where + graftpoint = "export.tree" diff --git a/doc/design/exporting_trees_to_special_remotes.mdwn b/doc/design/exporting_trees_to_special_remotes.mdwn index 835a86640..7e5700fae 100644 --- a/doc/design/exporting_trees_to_special_remotes.mdwn +++ b/doc/design/exporting_trees_to_special_remotes.mdwn @@ -133,12 +133,6 @@ key/value stores. The content of a file can change, and if multiple repositories can export a special remote, they can be out of sync about what files are exported to it. -To avoid such problems, when updating an exported file on a special remote, -the key could be recorded there too. But, this would have to be done -atomically, and checked atomically when downloading the file. Special -remotes lack atomicity guarantees for file storage, let alone for file -retrieval. - Possible solution: Make exporttree=true cause the special remote to be untrusted, and rely on annex.verify to catch cases where the content of a file on a special remote has changed. This would work well enough @@ -205,13 +199,8 @@ In this case, git-annex knows both exported trees. Have the user provide a tree that resolves the conflict as they desire (it could be the same as one of the exported trees, or some merge of them or an entirely new tree). The UI to do this can just be another `git annex export $tree --to remote`. -To resolve, diff each exported tree in turn against the resolving tree. If a -file differs, re-export that file. In some cases this will do unncessary -re-uploads, but it's reasonably efficient. - -The documentation should suggest strongly only exporting to a given special -remote from a single repository, or having some other rule that avoids -export conflicts. +To resolve, diff each exported tree in turn against the resolving tree +and delete all files that differ. ## when to update export.log for efficient resuming of exports |