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\subsection{darcs check}
\begin{code}
module Darcs.Commands.Check ( check ) where
import Control.Monad ( when, unless )
import System.Exit ( ExitCode(..), exitWith )

import Darcs.Commands ( DarcsCommand(..), nodefaults )
import Darcs.Arguments ( DarcsFlag( Quiet, NoTest ),
                        partial_check, notest,
                        leave_test_dir, working_repo_dir,
                      )
import Darcs.Repository.Repair( replayRepository,
                              RepositoryConsistency(..) )
import Darcs.Repository ( Repository, amInRepository, withRepository, ($-), slurp_recorded,
                          testTentative )
import Darcs.Patch ( RepoPatch, showPatch )
import Darcs.Ordered ( FL(..) )
import Darcs.Diff ( unsafeDiff )
import Darcs.Repository.Prefs ( filetype_function )
import Printer ( putDocLn, text, ($$), (<+>) )
\end{code}

\options{check}

\haskell{check_description}
\begin{code}
check_description :: String
check_description = "Check the repository for consistency."
\end{code}
Check verifies that the patches stored in the repository, when successively
applied to an empty tree, properly recreate the stored pristine tree.

\begin{options}
--complete, --partial
\end{options}

If you have a checkpoint of the repository (as is the case if you got the
repository originally using \verb!darcs get --partial!), by default
\verb'darcs check'
will only verify the contents since the most recent checkpoint.  You can
change this behavior using the \verb!--complete! flag.

\begin{code}
check_help :: String
check_help =
 "Check verifies that the patches stored in the repository, when successively\n"++
 "applied to an empty tree, properly recreate the stored pristine tree.\n"
\end{code}

\begin{code}
check :: DarcsCommand
check = DarcsCommand {command_name = "check",
                      command_help = check_help,
                      command_description = check_description,
                      command_extra_args = 0,
                      command_extra_arg_help = [],
                      command_command = check_cmd,
                      command_prereq = amInRepository,
                      command_get_arg_possibilities = return [],
                      command_argdefaults = nodefaults,
                      command_advanced_options = [],
                      command_basic_options = [partial_check,
                                              notest,
                                              leave_test_dir,
                                              working_repo_dir
                                             ]}
\end{code}

\begin{code}
check_cmd :: [DarcsFlag] -> [String] -> IO ()
check_cmd opts _ = withRepository opts $- \repo -> check' repo opts

check' :: (RepoPatch p) => Repository p -> [DarcsFlag] -> IO ()
check' repository opts = do
    res <- replayRepository repository opts $ \ state -> do
      case state of
        RepositoryConsistent -> do
          putInfo $ text "The repository is consistent!"
          unless (NoTest `elem` opts) $ testTentative repository
          return ExitSuccess
        BrokenPristine newpris -> do
          brokenPristine newpris
          return $ ExitFailure 1
        BrokenPatches newpris _ -> do
          brokenPristine newpris
          putInfo $ text "Found broken patches."
          return $ ExitFailure 1
    exitWith res
   where 
     brokenPristine newpris = do
         putInfo $ text "Looks like we have a difference..."
         mc <- slurp_recorded repository
         ftf <- filetype_function
         putInfo $ case unsafeDiff opts ftf newpris mc of
                        NilFL -> text "Nothing"
                        patch -> text "Difference: " <+> showPatch patch
         putInfo $ text ""
                     $$ text "Inconsistent repository!"
     putInfo s = when (not $ Quiet `elem` opts) $ putDocLn s
\end{code}

\input{Darcs/Test.lhs}

\begin{options}
--no-test
\end{options}

If you just want to check the consistency of your repository without
running the test, you can call darcs check with the \verb!--no-test!
option.