Unexpected counterexample to `decode . encode = Just`

[meiersi]

Using yaml-0.8.2.1 imported as Y

*Schiller> Y.encode ( [""] :: [String])
"- \n"
*Schiller> Y.decode $ Y.encode ( [""] :: [String]) :: Maybe [String]
Nothing

The problem seems to be the encoding of the empty string without any quotes.

*Schiller> Y.encode ( ["a"] :: [String])
"- a\n"
*Schiller> Y.decode $ Y.encode ( ["a"] :: [String]) :: Maybe [String]
Just ["a"]
*Schiller> 

I don't know YAML well, but this is unexpected. Using aeson, imported as A, the result looks as expected.

*Schiller> A.encode ( [""] :: [String])
Chunk "[\"\"]" Empty
*Schiller> A.decode $ A.encode ( [""] :: [String]) :: Maybe [String]
Just [""]
*Schiller> 

It is thus not one of the pitfalls (http://hackage.haskell.org/packages/archive/aeson/0.6.1.0/doc/html/Data-Aeson.html#g:6) that one has to know about when using aeson.

[snoyberg]

Thanks for pointing this out, it was triggered by some recent changes to do prettier printing. I just pushed a change to fix it, and released version 0.8.2.2 to Hackage. If there are still problems, please let me know.

[meiersi]

You're welcome. I will let you know, if I encounter further problems.