repaired tests, clean encodeUtf8 to return Done r rather than yield B.empty >> Done r when decoding was perfect

2 files changed, 11 insertions, 9 deletions

diff --git a/Pipes/Text.hs b/Pipes/Text.hs
index e8b64dc..74d2023 100644
--- a/Pipes/Text.hs
+++ b/Pipes/Text.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE RankNTypes, TypeFamilies, NoMonomorphismRestriction #-}
+{-# LANGUAGE RankNTypes, TypeFamilies #-}
 
 {-| This module provides @pipes@ utilities for \"text streams\", which are
     streams of 'Text' chunks.  The individual chunks are uniformly @strict@, but 
@@ -587,20 +587,23 @@ count :: (Monad m, Num n) => Text -> Producer Text m () -> m n
 count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c))
 {-# INLINABLE count #-}
 
--- | Transform a Pipe of 'ByteString's expected to be UTF-8 encoded
--- into a Pipe of Text
+-- | Transform a Pipe of 'ByteString's expected to be UTF-8 encoded into a Pipe of Text
+-- returning a Pipe of ByteStrings that begins at the point of failure.
 
 decodeUtf8 :: Monad m => Producer ByteString m r -> Producer Text m (Producer ByteString m r)
 decodeUtf8 = go B.empty PE.streamDecodeUtf8 where
   go carry dec0 p = do 
      x <- lift (next p) 
-     case x of Left r -> return (do yield carry
-                                    return r)
+     case x of Left r -> if B.null carry 
+                           then return (return r)      -- all input was consumed
+                           else return (do yield carry -- a potentially valid fragment remains
+                                           return r)
+                                           
                Right (chunk, p') -> case dec0 chunk of 
                    PE.Some text carry2 dec -> do yield text
                                                  go carry2 dec p'
                    PE.Other text bs -> do yield text 
-                                          return (do yield bs
+                                          return (do yield bs -- an invalid blob remains
                                                      p')
 
 -- | Splits a 'Producer' after the given number of characters
diff --git a/test/Test.hs b/test/Test.hs
index 53dca6a..f2bf17b 100644
--- a/test/Test.hs
+++ b/test/Test.hs
@@ -23,7 +23,6 @@ import qualified Pipes.Text.Internal as PE
 import qualified Pipes.Text as TP
 import qualified Pipes.ByteString as BP 
 import qualified Pipes as P 
-import Debug.Trace
 
 main :: IO ()
 main = defaultMain [tests]
@@ -31,7 +30,7 @@ main = defaultMain [tests]
 
 tests = testGroup "stream_decode" [
   -- testProperty "t_utf8_incr_valid" t_utf8_incr_valid,
---  testProperty "t_utf8_incr_mixed" t_utf8_incr_mixed ] -- ,
+  testProperty "t_utf8_incr_mixed" t_utf8_incr_mixed ,
   testProperty "t_utf8_incr_pipe" t_utf8_incr_pipe]
 
 t_utf8_incr_valid  = do
@@ -72,7 +71,7 @@ t_utf8_incr_pipe  = do
        Positive n  <- arbitrary  
        txt         <- genUnicode
        let chunkSize = mod n 7 + 1
-           bytesLength = mod 3 m
+           bytesLength = mod 10 m
        forAll (vector bytesLength) $ 
               (BL.toStrict . BP.toLazy . roundtrip . P.each . chunk chunkSize . appendBytes txt) 
               `eq`