git-annex/Annex/GitOverlay.hs
Joey Hess 097605e2e9
git's handing of relative GIT_INDEX_FILE is more insane than I thought; always make absolute
This is actually worse than I thought; when git is being run with a
detached work tree, GIT_INDEX_FILE is treated as a path relative to CWD,
instead of the normal behavior of relative the top of the work tree.

This seems to make it basically impossible for any program that wants to
use GIT_INDEX_FILE to use anything other than an absolute path to it; there
are too many configurations to keep straight that can change how git
interprets what should be a simple relative path to a file.

(I have complained to the git developers.)
2016-05-22 15:02:55 -04:00

78 lines
2.3 KiB
Haskell

{- Temporarily changing the files git uses.
-
- Copyright 2014-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.GitOverlay where
import qualified Control.Exception as E
import Annex.Common
import Git
import Git.Types
import Git.Index
import Git.Env
import qualified Annex
{- Runs an action using a different git index file. -}
withIndexFile :: FilePath -> Annex a -> Annex a
withIndexFile f a = do
f' <- liftIO $ indexEnvVal f
withAltRepo
(\g -> addGitEnv g indexEnv f')
(\g g' -> g' { gitEnv = gitEnv g })
a
{- Runs an action using a different git work tree.
-
- Smudge and clean filters are disabled in this work tree. -}
withWorkTree :: FilePath -> Annex a -> Annex a
withWorkTree d = withAltRepo
(\g -> return $ g { location = modlocation (location g), gitGlobalOpts = gitGlobalOpts g ++ disableSmudgeConfig })
(\g g' -> g' { location = location g, gitGlobalOpts = gitGlobalOpts g })
where
modlocation l@(Local {}) = l { worktree = Just d }
modlocation _ = error "withWorkTree of non-local git repo"
disableSmudgeConfig = map Param
[ "-c", "filter.annex.smudge="
, "-c", "filter.annex.clean="
]
{- Runs an action with the git index file and HEAD, and a few other
- files that are related to the work tree coming from an overlay
- directory other than the usual. This is done by pointing
- GIT_COMMON_DIR at the regular git directory, and GIT_DIR at the
- overlay directory.
-
- Needs git 2.2.0 or newer.
-}
withWorkTreeRelated :: FilePath -> Annex a -> Annex a
withWorkTreeRelated d = withAltRepo modrepo unmodrepo
where
modrepo g = do
g' <- addGitEnv g "GIT_COMMON_DIR" =<< absPath (localGitDir g)
g'' <- addGitEnv g' "GIT_DIR" d
return (g'' { gitEnvOverridesGitDir = True })
unmodrepo g g' = g'
{ gitEnv = gitEnv g
, gitEnvOverridesGitDir = gitEnvOverridesGitDir g
}
withAltRepo
:: (Repo -> IO Repo)
-- ^ modify Repo
-> (Repo -> Repo -> Repo)
-- ^ undo modifications; first Repo is the original and second
-- is the one after running the action.
-> Annex a
-> Annex a
withAltRepo modrepo unmodrepo a = do
g <- gitRepo
g' <- liftIO $ modrepo g
r <- tryNonAsync $ do
Annex.changeState $ \s -> s { Annex.repo = g' }
a
Annex.changeState $ \s -> s { Annex.repo = unmodrepo g (Annex.repo s) }
either E.throw return r