% Copyright (C) 2002-2005 David Roundy % % 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. \darcsCommand{trackdown} \begin{code}
module Darcs.Commands.TrackDown ( trackdown ) where
import Prelude hiding ( init )
import System.Exit ( ExitCode(..) )
import System.Cmd ( system )
import System.IO ( hFlush, stdout )

import Darcs.Commands ( DarcsCommand(..), nodefaults )
import Darcs.Arguments ( DarcsFlag(SetScriptsExecutable, Bisect), workingRepoDir, bisect,
setScriptsExecutableOption )
import Darcs.Hopefully ( hopefully )
import Darcs.Repository ( amInRepository, readRepo, withRepoReadLock, ($-), withRecorded, setScriptsExecutable ) import Darcs.Witnesses.Ordered ( RL(..), (:<)(..), (+<+), reverseRL, splitAtRL, lengthRL, mapRL, mapFL, mapRL_RL, concatRL ) import Darcs.Patch.Patchy ( Invert, Apply, ShowPatch ) import Darcs.Patch ( RepoPatch, Named, description, apply, invert ) import Darcs.Patch.Set ( newset2RL ) import Printer ( putDocLn ) import Darcs.Test ( getTest ) import Darcs.Lock ( withTempDir ) #include "gadts.h" trackdownDescription :: String trackdownDescription = "Locate the most recent version lacking an error." trackdownHelp :: String trackdownHelp = "Trackdown tries to find the most recent version in the repository which\n"++ "passes a test. Given no arguments, it uses the default repository test.\n"++ "Given one argument, it treats it as a test command. Given two arguments,\n"++ "the first is an initialization command with is run only once, and the\n"++ "second is the test command.\n\n"++ "Without the --bisect option, trackdown does linear search starting from head,\n"++ "and moving away from head. With the --bisect option, it does binary search.\n\n"++ "Under the assumption that failure is monotonous, trackdown produces\n"++ "the same result with and without --bisect. (Monotonous means that when\n"++ "moving away from head, the test result changes only once from \"fail\" to \"ok\".)\n"++ "If failure is not monotonous, any one of the patches that break the test is\n"++ "found at random." trackdown :: DarcsCommand trackdown = DarcsCommand {commandName = "trackdown", commandHelp = trackdownHelp, commandDescription = trackdownDescription, commandExtraArgs = -1, commandExtraArgHelp = ["[[INITIALIZATION]", "COMMAND]"], commandCommand = trackdownCmd, commandPrereq = amInRepository, commandGetArgPossibilities = return [], commandArgdefaults = nodefaults, commandAdvancedOptions = [setScriptsExecutableOption], commandBasicOptions = [workingRepoDir, bisect]} trackdownCmd :: [DarcsFlag] -> [String] -> IO () trackdownCmd opts args = withRepoReadLock opts$- \repository -> do
(init,test) <- case args of
[] ->
do t <- getTest opts
return (return ExitSuccess, t)
[cmd] ->
do putStrLn $"Tracking down command:\n"++cmd return$ (return ExitSuccess, system cmd)
[init,cmd] ->
do putStrLn $"Initializing with command:\n"++init putStrLn$ "Tracking down command:\n"++cmd
return $(system init, system cmd) _ -> fail "Trackdown expects zero to two arguments." withRecorded repository (withTempDir "trackingdown")$ \_ -> do
when (SetScriptsExecutable elem opts) setScriptsExecutable
_ <- init
(if Bisect elem opts
then trackBisect
else trackNextLinear) opts test (mapRL_RL hopefully . newset2RL $patches) -- | linear search (without --bisect) trackNextLinear :: RepoPatch p => [DarcsFlag] -> IO ExitCode -> RL (Named p) C(x y) -> IO () trackNextLinear opts test (p:<:ps) = do test_result <- test if test_result == ExitSuccess then putStrLn "Success!" else do apply opts (invert p) catch \e -> fail ("Bad patch:\n" ++ show e) putStrLn "Trying without the patch:" putDocLn$ description $invert p hFlush stdout trackNextLinear opts test ps trackNextLinear _opts test NilRL = do test_result <- test if test_result == ExitSuccess then putStrLn "Success!" else putStrLn "Noone passed the test!" -- | binary search (with --bisect) trackBisect :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> IO ExitCode -> RL p C(x y) -> IO () trackBisect opts test NilRL = do test_result <- test if test_result == ExitSuccess then putStrLn "Success!" else putStrLn "Noone passed the test!" trackBisect opts test ps = do test_result <- test if test_result == ExitSuccess then putStrLn ("Test does not fail on head.") else trackNextBisect opts curr_prog test BisectRight (patchTreeFromRL ps) where curr_prog = (1, 1 + round ((logBase 2$ fromIntegral $lengthRL ps) :: Double)) :: (Int,Int) -- | Bisect Patch Tree data PatchTree p C(x y) where Leaf :: p C(x y) -> PatchTree p C(x y) Fork :: PatchTree p C(y z) -> PatchTree p C(x y) -> PatchTree p C(x z) -- | Direction of Bisect trackdown data BisectDir = BisectLeft | BisectRight deriving Show -- | Progress of Bisect type BisectState = (Int, Int) -- | Create Bisect PatchTree from the RL patchTreeFromRL :: (Invert p, ShowPatch p, Apply p) => RL p C(x y) -> PatchTree p C(x y) patchTreeFromRL (l :<: NilRL) = Leaf l patchTreeFromRL xs = case splitAtRL (lengthRL xs div 2) xs of (l :< r) -> Fork (patchTreeFromRL l) (patchTreeFromRL r) -- | Convert PatchTree back to RL patchTree2RL :: (Invert p) => PatchTree p C(x y) -> RL p C(x y) patchTree2RL (Leaf p) = p :<: NilRL patchTree2RL (Fork l r) = (patchTree2RL l) +<+ (patchTree2RL r) -- | Iterate the Patch Tree trackNextBisect :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> BisectState -> IO ExitCode -> BisectDir -> PatchTree p C(x y) -> IO () trackNextBisect opts (dnow, dtotal) test dir (Fork l r) = do putStr ("Trying " ++ show dnow ++ "/" ++ show dtotal ++ " sequences...\n") hFlush stdout case dir of BisectRight -> jumpHalfOnRight opts l -- move in temporary repo BisectLeft -> jumpHalfOnLeft opts r -- within given direction test_result <- test -- execute test on repo case test_result of ExitSuccess -> trackNextBisect opts (dnow+1, dtotal) test BisectLeft l -- continue left (to the present) _ -> trackNextBisect opts (dnow+1, dtotal) test BisectRight r -- continue right (to the past) trackNextBisect _ _ _ _ (Leaf p) = do putStrLn ("Last recent patch that fails the test (assuming monotony in the given range):") putDocLn (description p) jumpHalfOnRight :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> PatchTree p C(x y) -> IO () jumpHalfOnRight opts l = unapplyRL opts (patchTree2RL l) jumpHalfOnLeft :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> PatchTree p C(x y) -> IO () jumpHalfOnLeft opts r = applyRL opts (patchTree2RL r) applyRL :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> RL p C(x y) -> IO () applyRL opts patches = sequence_ (mapFL (safeApply opts) (reverseRL$ patches))

unapplyRL :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> RL p C(x y) -> IO ()
unapplyRL opts patches = sequence_ (mapRL ((safeApply opts) . invert) patches)

safeApply :: (Invert p, ShowPatch p, Apply p) => [DarcsFlag] -> p C(x y) -> IO ()
safeApply opts p = apply opts p catch (\msg -> fail ("Bad patch (during trackdown --bisect):\n" ++ show msg))

\end{code} Trackdown is helpful for locating when something was broken. It creates a temporary directory with the latest repository content in it and cd to it. First, and only once, it runs the initialization command if any, for example \begin{verbatim} 'autoconf; ./configure >/dev/null' \end{verbatim} Then it runs the test command, for example \begin{verbatim} 'make && cd tests && sh /tmp/test.sh' \end{verbatim} While the test command exits with an error return code, darcs unapplies'' one patch from the version controlled files to retrieve an earlier version, and repeats the test command. If the test command finally succeeds, the name of the hunted down patch is found in the output before the last test run. FIXME: There is a new --bisect feature that needs to be finished. Open points: GATDs. polish debugging output and add --verbose flag; documentation (online help's already there); update this documentation. See Issue1208. FIXME: I also would like to add an interface by which you can tell it which patches it should consider not including. Without such a feature, the following command: \begin{verbatim} % darcs trackdown 'make && false' \end{verbatim} would result in compiling every version in the repository--which is a rather tedious prospect. FIXME: There is a third more besides linear (no --bisect) and binary (--bisect) search, which is described on bugs.darcs.net in Issue1638. The idea is that no total order on the set of patches is assumed. Delta trackdown yields the minimum number of patches that you would need to obliterate in order to make the test succeed. \subsubsection{Example usage} If you want to find the last version of darcs that had a FIXME note in the file Record.lhs, you could run \begin{verbatim} % darcs trackdown 'grep FIXME Record.lhs' \end{verbatim} To find the latest version that compiles, you can run \begin{verbatim} % darcs trackdown 'autoconf' './configure && make' \end{verbatim} Trackdown can also be used to see how other features of the code changed with time. For example \begin{verbatim} % darcs trackdown 'autoconf; ./configure' \ "make darcs > /dev/null && cd ~/darcs && time darcs check && false" \end{verbatim} would let you see how long darcs check' takes to run on each previous version of darcs that will actually compile. The `\verb!&& false!'' ensures that trackdown keeps going.