cabal-helper provides a library which wraps the internal use of
anexecutable to lift the restrictions imposed by linking against versions of
7.10. This has the pleasant side effect of isolating the user
from having to deal with Cabal version changes manually as
can simply recompile it's helper program automatically as needed.
cabal-helper uses a wrapper executable to compile the actual cabal-helper
executable at runtime while linking against an arbitrary version of
Cabal. This runtime-compiled helper executable is then used to extract
various bits and peices from Cabal's on disk state (dist/setup-config)
written by it's configure command.
In addition to this the wrapper executable also supports installing any version of Cabal from hackage in case it cannot be found in any available package database. The wrapper installs these instances of the Cabal library into a private package database so as to not interfere with the user's packages.
Furthermore the wrapper supports one special case namely reading a state file for Cabal itself. This is needed as Cabal compiles it's Setup.hs using itself and not using any version of Cabal installed in any package database.
cabal-helper can compile with
Cabal >= 1.14 but requires
Cabal >= 1.16