[DEVOPS-1061] pkgs/generate.sh: Also generate cabal.project.freeze

Author: rvl

cabal.project

@@ -1,8 +1,3 @@
 packages:
   */*.cabal
   */test/*.cabal
-
--- not sure why the cabal solver wants to download and build a newer beam-sqlite
-constraints: beam-sqlite == 0.3.2.1
--- allow-newer: all
--- allow-older: all

cabal.project.freeze

@@ -186,25 +186,19 @@ Enter the `nix-shell`:
 
     [nix-shell:~/cardano-sl]$ nix-shell
 
-Let cabal find its dependencies (already provided by the `nix-shell`):
-
-    [nix-shell:~/cardano-sl]$ cabal new-configure
-
-After that, to build all cardano-sl packages:
+Then build all cardano-sl packages:
 
     [nix-shell:~/cardano-sl]$ cabal new-build all
 
+All dependencies necessary for the Cabal build are provided by the
+`nix-shell`. The package versions are pinned in the
+`cabal.project.freeze` file, which is automatically generated from
+`stack.yaml` (via `stack2nix`).
+
 To start a GHCi session for a component (wallet-new for example), run:
 
     [nix-shell:~/cardano-sl]$ cabal new-repl cardano-sl-wallet-new
 
-### Known issues
-
- - `cabal-install` is not provided by the Nix shell environment. You
-   have to install it yourself.
- - There needs to be a package version override in `cabal.project` for
-   some unknown reason.
-
 
 ## Daedalus Wallet
 

docs/how-to/build-cardano-sl-and-daedalus-from-source-code.md

@@ -39,4 +39,9 @@ in
     # Generate cardano-sl package set
     stack2nix --platform x86_64-linux --hackage-snapshot "${hackageSnapshot}" -j8 --test --bench --no-indent ./.. > default.nix.new
     mv default.nix.new default.nix
+
+    # Generate cabal new-freeze file from package set
+    cp --remove-destination --no-preserve=mode \
+        $(nix-build ../shell.nix -A cabalProjectFreeze --no-out-link) \
+        ../cabal.project.freeze
   ''

pkgs/regen.nix

@@ -7,11 +7,16 @@ with pkgs;
 let
   localLib = import ./lib.nix;
 
-  getCardanoSLDeps = with lib;
-    ps: filter (drv: !(localLib.isCardanoSL drv.name))
-    (concatMap haskell.lib.getHaskellBuildInputs
-     (attrValues (filterAttrs isWantedDep ps)));
-  isWantedDep = name: drv: localLib.isCardanoSL name && !(drv ? "gitrev");
+  # Filters a haskell package set and returns only the packages which
+  # are (transitive) dependencies of the cardano-sl packages.
+  getCardanoSLDeps = with lib; let
+    notCardano = drv: !(localLib.isCardanoSL drv.name);
+    isTopLevel = name: drv: localLib.isCardanoSL name && (drv ? "override");
+    getTopLevelDrvs = ps: attrValues (filterAttrs isTopLevel ps);
+    sorted = ps: attrValues (listToAttrs (map (drv: { name = drv.pname; value = drv; }) ps));
+  in
+    ps: sorted (filter notCardano (concatMap haskell.lib.getHaskellBuildInputs (getTopLevelDrvs ps)));
+
   ghc = iohkPkgs.ghc.withPackages getCardanoSLDeps;
 
   stackDeps = [
@@ -59,6 +64,20 @@ let
       exit
     '';
   };
+
+  # Writes out a cabal new-freeze file containing the exact same
+  # dependency versions as are provided by this shell.
+  cabalProjectFreeze = let
+    contents = ''
+      -- This file is automatically generated from stack.yaml.
+      constraints: ${constraints}
+    '';
+    constraints = lib.concatMapStringsSep ",\n             "
+      makeConstraint (getCardanoSLDeps iohkPkgs);
+    makeConstraint = dep: "${dep.pname} ==${dep.version}";
+  in
+    pkgs.writeText "cabal.project.freeze" contents;
+
 in cardanoSL // {
-  inherit fixStylishHaskell;
+  inherit fixStylishHaskell cabalProjectFreeze;
 }