Use extra-packages in modules/hackage-project.nix (#2310)

This is a step towards removing the dependency on `hackage.nix`.

Instead of looking up the source for a tool using `hackage.nix` it lets `make-install-plan` to it using the cabal planner (based on an `extra-packages:` entry in a `cabal.project` file).

Author: hamishmack

.github/workflows/upload-artifacts.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Wait for nix-tools meta job
         uses: input-output-hk/actions/wait-for-hydra@angerman/support-prs
         with:
-          status: 'ci/hydra-build:nix-tools'
+          check: 'nix-tools'
 
       - name: "Pull nix-tools"
         run: |

lib/load-cabal-plan.nix

@@ -100,7 +100,9 @@ in {
                     then import (nixFilesDir + "/cabal-files/${p.pkg-name}.nix")
                   else if builtins.pathExists (nixFilesDir + "/.plan.nix/${p.pkg-name}.nix")
                     then import (nixFilesDir + "/.plan.nix/${p.pkg-name}.nix")
-                  else (((hackage.${p.pkg-name}).${p.pkg-version}).revisions).default) (args // { hsPkgs = {}; });
+                  else
+                    # TODO make this an error?
+                    __trace "WARNING no `.nix` file for ${p.pkg-name} in ${nixFilesDir}." {}) (args // { hsPkgs = {}; });
               in pkgs.lib.optionalAttrs (p ? pkg-src-sha256) {
                 sha256 = p.pkg-src-sha256;
               } // pkgs.lib.optionalAttrs (p.pkg-src.type or "" == "source-repo") {