Finding a Compiler Plugin with --ghc-options=" -package=compilerplugin

[tkvogt]

My goal is to to run a compiler plugin over all packages in a snapshot. This usecase is probably very rare, but the solution I used so far with just cabal could only compile half of stackage (quite disappointing).

Before using stack I made a new sandbox with cabal, compiled the plugin in this sandbox, made a backup of this sandbox (to safe time). Then the sandbox was recreated for each package, that was compiled with the plugin.

I wonder how to do something similar with stack. Maybe install the plugin in the snapshot (to avoid recompilation)?
My tests also show that ghc can only find packages that are in its global database (which is maybe a bug). I am willing to look into all this and write a pull request.

This part of a shake script runs but doesn't work:

    putNormal "\nBuild ghc-core-graph (the compiler plugin)"
    () <- cmd Shell (Cwd ("be" </> "ghc-core-graph")) ("stack clean")
    () <- cmd Shell (Cwd ("be" </> "ghc-core-graph")) ("stack setup")
    () <- cmd Shell (Cwd ("be" </> "ghc-core-graph")) ("stack build")

    forP (zip [0..] packages) (\(i, package) -> do
      Exit c <- cmd Shell (Cwd ("be" </> "ghc-core-graph"))
       ("stack build "++ package ++" --verbose --ghc-options=\" -package=ghc-core-graph -fplugin=GhcPlugins.Optimind\"")

[mgsloan]

The docs for ghc-options / apply-ghc-options may be helpful - https://docs.haskellstack.org/en/stable/yaml_configuration/#ghc-options . You probably want to have a stack.yaml with something like

ghc-options:
  "$everything": -package=ghc-core-graph -fplugin=GhcPlugins.Optimind

Note that this won't rebuild stuff in the global db (things like base). I don't know of a good way to force a rebuild of baser other than asking for a different version than what's in the global DB that came with the compiler. Note that this will mean any package that transitively depends on ghc as a library won't be able to be used.

This will hopefully be resolved with implicit snapshots (#1265 , reopened in #3330). Until that's implemented, you will need to make sure that nothing has been built yet in the snapshot you're using. One way to do that is to do compiler: ghc-8.2.1 and rely entirely on extra-deps instead of using snapshots.

In lieu of extra-deps we could consider having some option that promotes everything to the local DB. This way, deleting the local DB could force a full rebuild.

[mpilgrem]

I am going to close this issue given the passage of time.