#700: seemingly too liberal behaviour on overlapping dependency constraints across packages ---------------------------------+------------------------------------------ Reporter: kowey | Owner: Type: defect | Status: new Priority: normal | Milestone: Component: cabal-install tool | Version: 1.6.0.3 Severity: normal | Keywords: Difficulty: unknown | Ghcversion: Platform: | ---------------------------------+------------------------------------------ Comment(by duncan): So we believe the problem is that the `mmap` package contains C code and so when multiple versions of that package are linked into one program then the linker just picks the first occurrence of the C functions. GHC packages are designed to allow linking multiple versions however this property is broken by including unversioned C symbols in the package. There are a number of possible solutions and workarounds: * Solution: avoid using C code in the `mmap` package * Solution: use versioned C symbol names (versioned with the package name/version) * Workadound: avoid linking multiple versions of the `mmap` package. See ticket #701 for some more general ideas. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/700#comment:4 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects