Reintroduce buildFromSdist (enable it by default) (#286)

CHANGELOG.md

@@ -12,7 +12,7 @@
   - #223 Make `devShell.tools` a `lazyAttrsOf` (lazy evaluation of values)
 - Breaking changes
   - #221: Switch to `buildFromSdist`, to allow using non-standard package sets (wherein `cabal-install` is otherwise built without using user's overrides)
-  - #253: Turn off `buildFromSdist` by default. It can now be enabled manually by setting `settings.<name>.buildFromSdist` to `true`.
+    - #253: Enable controlling `buildFromSdist` through `settings.<name>.buildFromSdist`. (This was turned off by default originally, but was turned on by default in #286)
 - #271: Change all `types.attrsOf` to `types.lazyAttrsOf`. If you use `lib.mkIf` for `attrsOf` values (not `submodule` options), use `lib.optionalAttrs` instead. This fixes #270 (`basePackages`) and improves performance.
 
 ## 0.4.0 (Aug 22, 2023)

nix/modules/project/defaults.nix

@@ -61,7 +61,7 @@ in
         If you have a `cabal.project` file (under `projectRoot`), those packages
         are automatically discovered. Otherwise, the top-level .cabal file is
         used to discover the only local package.
-        
+
         haskell-flake currently supports a limited range of syntax for
         `cabal.project`. Specifically it requires an explicit list of package
         directories under the "packages" option.
@@ -85,9 +85,9 @@ in
       default =
         let
           globalSettings = {
-            # We disable this by default because it causes breakage.
-            # See https://github.com/srid/haskell-flake/pull/253
-            buildFromSdist = lib.mkDefault false;
+            # Make sure all files we use are included in the sdist, as a check
+            # for release-worthiness.
+            buildFromSdist = lib.mkDefault true;
           };
           localSettings = { name, package, config, ... }:
             lib.optionalAttrs (package.local.toDefinedProject or false) {

nix/modules/project/settings/default.nix

@@ -50,7 +50,7 @@ in
       let
         applySettingsFor = name: mod:
           let
-            cfg = (lib.evalModules {
+            cfg' = (lib.evalModules {
               modules = [
                 # Settings spec
                 ./all.nix
@@ -71,13 +71,19 @@ in
                 config = cfg;
               });
             }).config;
+            cfg = traceSettings name cfg';
+            # HACK: buildFromSdist must apply *last*
+            # cf. https://github.com/srid/haskell-flake/pull/252
+            # In future, we can refactor this as part of https://github.com/srid/haskell-flake/issues/285
+            impl = lib.attrsets.removeAttrs cfg.impl [ "buildFromSdist" ];
+            fns = lib.attrValues impl ++ [ cfg.impl.buildFromSdist ];
           in
           lib.pipe super.${name} (
             # TODO: Do we care about the *order* of overrides?
             # Might be relevant for the 'custom' option.
             lib.concatMap
               (impl: impl)
-              (lib.attrValues (traceSettings name cfg).impl)
+              fns
           );
       in
       lib.mapAttrs applySettingsFor project.config.settings;