This is a survey of the problems in updating to Cabal-1.2. (This is independent of the problems in updating to GHC-6.8, though of course many people will encounter both at the same time.) I've compiled The Setup.(l)hs scripts of all 248 packages (394 package-version pairs) on hackage with the new Cabal-1.2 library. Of those, the Setup scripts from 20 packages fail to compile (there are 31 package-version pairs). 4 more compile but with warnings. I've categorised the failures by their cause & remedy: ------------------------------ There are several packages which currently use custom code in the Setup.hs script that can now be replaced entirely by using the new configurations feature. They are doing things like picking the dependencies based on the ghc version or the operating system. This is exactly what configurations are for. These packages can then use the "build-type: Simple" and the trivial Setup.hs script. cabalmdvrpm-0.0.1 cabalrpmdeps-0.0.3 HDBC-odbc-1.0.1.0 hslogger-1.0.2 MissingH-0.18.2 tar-0.1 unix-compat-0.1 hsql-odbc-1.7 (actually does compile but with a warning) ------------------------------ A similar case is using code to run an external program to discover the correct build flags for a package. In general this still needs to use custom code but in the common case of using the "pkg-config" program we can take advantage of the pkg-config support in Cabal-1.2 and again get away with using the build-type: Simple and the trivial Setup.hs script. hsql-sqlite3-1.7 ------------------------------ An API change in the "UserHook" hooks interface that affected many Setup scripts was that the result type was changed from IO ExitCode to just IO (). Then instead of returning codes all over the place (which were not being consistently checked) we now use IO exceptions instead. So Setup scripts which used to return ExitSuccess can now return () and ExitFailure n can be replaced by exitWith (ExitFailure n). debian-1.0 hburg-1.0 YamlReference-0.1 to 0.5 ------------------------------ There are a number of packages where the Setup script makes extensive use of the internal API of Cabal's default build system. I'll mention each one briefly: fenfire-0.1: needs updating to use new PreProcessor abstraction. Can drop the local def of c2hs pre-processor as this hack is no longer required in the minimum version of c2hs that Cabal supports (and it probably would no longer work anyway). lhs2tex-1.12: requires significant work. It makes use of the Program abstraction and system for managing installation dirs both of which have changed significantly. hsql-mysql-1.7, hsql-postgresql-1.7: requires significant work. can be simplified by using the cabal api effectively and using configurations. These both call external config programs to find the right build flags. I posted an update to hsql-mysql-1.7 the other day as an example. alex-2.1.0, happy-1.16: requires significant work (though already done in darcs versions). Again these used the internal Program abstraction which changed significantly. yi-0.2, hint-0.1: These both try to find ghc's libdir. The both could be significantly simplified by doing things in the 'proper' way which is to use the HookedBuildInfo stuff rather than writing little .ghc-libdir files. xmobar-0.3.1-0.7: The Setup.hs for this package completely re-implements the haddock command to customise the way docs are generated for executables. This is no longer necessary in Cabal-1.2 as it provides the features required. So the Setup.hs can be replaced with default and use build-type: Simple. ------------------------------ Packages for which Setup.hs compiles with a warning with Cabal-1.2: These three packages add a feature that was missing in Cabal-1.1.6 but is now present in Cabal-1.2. They add a --ghc-option= and --configure-option= flag to the configure command. Cabal-1.2 implements this generically for all programs that it knows about (and the programs it knows about can be extended by the Setup script). So again, these can use build-type: Simple and the trivial Setup script. cgi-3001.1.3 filepath-1.0 X11-1.2.2 One immediate cause of problems is Setup scripts importing Distribution.PreProcess, Distribution.Program which have moved under Distribution.Simple. I could add re-exports for both as I did for Distribution.Setup however both modules have changed significantly so any Script that actually uses these modules needs changing anyway, so theres no particular advantage to providing a module re-export crutch. I might make module Distribution.Simple.Utils export rawSystemVerbose again since some scripts use it. Though all those that do have other problems as well. So overall that's not too bad. Less than 10% of the hackage packages are affected by the significant internal changes in Cabal-1.2. Of those, only 9 packages need significant work to update their Setup scripts and 12 others can eliminate their custom Setup code completely using new features in Cabal-1.2. The remaining 3 need only minor changes. Duncan