Darcs fails with error 'Invalid URI' when cloning remote repo with darcs 
2.12.4 compiled on windows without curl lib (`stack install darcs --flag 
darcs:-curl`):


    D:\Projects>darcs clone http://hub.darcs.net/AriePeterson/console-
program

    darcs failed:  Invalid URI: 
http://hub.darcs.net/AriePeterson/console-
program\_darcs\hashed_inventory

The exact version of darcs is:

darcs compiled on Nov 15 2016, at 12:20:28

Context:

[TAG 2.12.4
Guillaume Hoffmann <guillaumh@gmail.com>**20160914143914
 Ignore-this: fee5b93a45e3a175e63e6fdb837ec4dc
]

Compiled with:

HTTP-4000.3.3
Win32-2.3.1.1
array-0.5.1.1
async-2.1.0
attoparsec-0.13.1.0
base-4.9.0.0
base16-bytestring-0.1.1.6
binary-0.8.3.0
bytestring-0.10.8.1
containers-0.5.7.1
cryptohash-0.11.9
data-ordlist-0.4.7.0
directory-1.2.6.2
fgl-5.5.3.0
filepath-1.4.1.0
graphviz-2999.18.1.2
hashable-1.2.4.0
haskeline-0.7.2.3
html-1.0.1.2
mmap-0.5.9
mtl-2.2.1
network-2.6.3.1
network-uri-2.6.1.0
old-time-1.1.0.3
parsec-3.1.11
process-1.4.2.0
random-1.1
regex-applicative-0.3.3
regex-compat-tdfa-0.95.1.4
sandi-0.4.0
tar-0.5.0.3
text-1.2.2.1
time-1.6.0.1
transformers-0.5.2.0
transformers-compat-0.5.1.4
unix-compat-0.4.2.0
utf8-string-1.0.1.1
vector-0.11.0.0
zip-archive-0.3.0.5
zlib-0.6.1.2

The operating system: Window 7 Professional, 64 bit

darcs 2.10.3 works well. The exact working version is:

darcs compiled on Nov 16 2016, at 17:15:31

Context:

[TAG 2.10.3
Guillaume Hoffmann <guillaumh@gmail.com>**20160129115730
 Ignore-this: 7eac9bf53015a285c43e6ea2b1e11a1d
]

Compiled with:

HTTP-4000.3.3
Win32-2.3.1.0
array-0.5.1.0
attoparsec-0.13.1.0
base-4.8.2.0
base16-bytestring-0.1.1.6
binary-0.7.5.0
bytestring-0.10.6.0
containers-0.5.6.2
cryptohash-0.11.9
data-ordlist-0.4.7.0
directory-1.2.2.0
filepath-1.4.0.0
hashable-1.2.4.0
haskeline-0.7.2.3
html-1.0.1.2
mmap-0.5.9
mtl-2.2.1
network-2.6.3.1
network-uri-2.6.1.0
old-time-1.1.0.3
parsec-3.1.11
process-1.2.3.0
random-1.1
regex-applicative-0.3.3
regex-compat-tdfa-0.95.1.4
sandi-0.3.6
tar-0.5.0.3
text-1.2.2.1
time-1.5.0.1
transformers-0.4.2.0
transformers-compat-0.4.0.4
unix-compat-0.4.1.4
utf8-string-1.0.1.1
vector-0.11.0.0
zip-archive-0.2.3.7
zlib-0.6.1.2

Hi Mihai,

thanks for the report; we'll try to look into it soon.

It may be related with the following changes in the 2.14 branch:

*
http://hub.darcs.net/darcs/darcs-2.12/patch/c0439f3febf6594426189cd7173944e5ad15d2b6
  "resolve issue2498: unconditionally use the Haskell HTTP package"

*
http://hub.darcs.net/darcs/darcs-2.12/patch/7cc493ec9cab956f45512143651200de1f6d09d4
  "require GHC 7.10 and time 1.5"

Hi Guillaume,

I checked a little bit and I am almost sure that the problem was introduced by the patch http://hub.darcs.net/darcs/darcs-
2.12/patch/109a5667e7cf1f4db879a2aa4076237229f90b09

This patch refactored some things about Darcs.Repository module. One of the things was, I quote, "consistent use of the </> operator from 
System.FilePath". The use of </> operator was extended to building url paths, which, in my opinion is not correct, since the url paths do not depend on 
the platform and local file system as I understand the </> operator does.

The previous code in Darcs.Repository,

    -copyBasicRepoPacked ::
    -  forall p wR wU wT. (RepoPatch p, ApplyState (PrimOf p) ~ Tree, ApplyState p ~ Tree)
    -  => Repository p wR wU wT
    -  -> Verbosity -> UseCache
    -  -> UMask -> RemoteDarcs
    -  -> WithWorkingDir
    -  -> IO ()
    -copyBasicRepoPacked r@(Repo fromDir _ _ _) verb useCache umask rdarcs withWorkingDir =
    -  do let hashURL = fromDir ++ packsDir ++ "pristine"
    -     mPackHash <- (Just <$> gzFetchFilePS hashURL Uncachable) `catchall` (return Nothing)
    -     let hiURL = fromDir ++ "/" ++ darcsdir ++ "/hashed_inventory"
    -     i <- gzFetchFilePS hiURL Uncachable
    -     let currentHash = BS.pack $ inv2pris i
    -     let copyNormally = copyBasicRepoNotPacked r verb useCache umask rdarcs withWorkingDir
    -     case mPackHash of
    -      Just packHash | packHash == currentHash
    -              -> ( copyBasicRepoPacked2 r verb useCache withWorkingDir
    -                    `catchall` do putStrLn "Problem while copying basic pack, copying normally."
    -                                  copyNormally)
    -      _       -> do putVerbose verb $ text "Remote repo has no basic pack or outdated basic pack, copying normally."
    -                    copyNormally

was replaced with the new code in Darcs.Repository.Clone:

    301:                           | copyBasicRepoPacked ::
    302:      ganesh@earth.li  #13 |   forall rt p wR wU wT. (IsRepoType rt, RepoPatch p, ApplyState (PrimOf p) ~ Tree, ApplyState p ~ Tree)
    303:      ganesh@earth.li  #17 |   => Repository rt p wR wU wT -- remote
    304:                           |   -> Repository rt p wR wU wT -- existing empty local repository
    305:  guillaumh@gmail.com   #3 |   -> Verbosity
    306:                           |   -> RemoteDarcs
    307: benjamin.franksen@he   #2 |   -> WithWorkingDir
    308:                           |   -> IO ()
    309:  guillaumh@gmail.com   #3 | copyBasicRepoPacked r@(Repo fromDir _ _ _) toRepo verb rdarcs withWorkingDir =
    310: benjamin.franksen@he   #2 |   do let hashURL = fromDir </> darcsdir </> packsDir </> "pristine"
    311:                           |      mPackHash <- (Just <$> gzFetchFilePS hashURL Uncachable) `catchall` (return Nothing)
    312:                           |      let hiURL = fromDir </> darcsdir </> "hashed_inventory"
    313:                           |      i <- gzFetchFilePS hiURL Uncachable
    314:                           |      let currentHash = BS.pack $ inv2pris i
    315:  guillaumh@gmail.com   #3 |      let copyNormally = copyBasicRepoNotPacked r toRepo verb rdarcs withWorkingDir
    316: benjamin.franksen@he   #2 |      case mPackHash of
    317:                           |       Just packHash | packHash == currentHash
    318:  guillaumh@gmail.com   #3 |               -> ( copyBasicRepoPacked2 r toRepo verb withWorkingDir
    319:                           |                     `catch` \(e :: SomeException) ->
    320:                           |                                do putStrLn ("Exception while getting basic pack:\n" ++ show e)
    321: benjamin.franksen@he   #2 |                                   copyNormally)
    322:                           |       _       -> do putVerbose verb $ text "Remote repo has no basic pack or outdated basic pack, copying normally."
    323:                           |                     copyNormally
    324:                           |


Please note that, in the previous version (one that works with Windows too), the URL was constructed using "/", but in the latest version, the url is 
constrtucted using System.FilePath </> operator.

Sorry my fault. Will try to fix.

I have pushed a patch that should fix this. Can you try again with a
freshly compiled darcs (http://darcs.net/screened)?