Cabal doesn't update binary symlinks

Question

I'm using OS X 10.8.2 with Haskell Platform 2012.4.0.0. When updating packages with cabal install , the binary symlinks don't get updated to point to the new binary versions. I must delete the symlink manually and reinstall the package. cabal install says:

Warning: could not create a symlink in /Users/thsoft/Library/Haskell/bin for elm because the file exists there already but is not managed by cabal. You can create a symlink for this executable manually if you wish. The executable file has been installed at /Users/thsoft/Library/Haskell/ghc-7.4.1/lib/Elm-0.7/bin/elm

I tried using sudo and specifying --symlink-bindir=/Users/thsoft/Library/Haskell/bin explicitly, but none of them helped. How could I fix this?

Answer 1

只需删除指定目录中存在的现有链接即可。

Answer 2

Tener's answer is correct: before 'cabal install'ing remove the links that would cause problems. I've had the same problem and this solved it.

(I couldn't make this a comment to Tener's answer since that would require more reputation than I have. :-( )