Split build and build-plan configuration

build.nix

@@ -29,7 +29,6 @@ src:
   #  Which drops the run-time dependency on the crates-io source thereby
   #  significantly reducing the Nix closure size.
 , removeReferencesToSrcFromDocs
-, cratePaths
 , pname
 , version
 , rustc
@@ -64,7 +63,6 @@ let
       inherit
         src
         doCheck
-        cratePaths
         version
         preBuild;
 

config.nix

@@ -1,10 +1,37 @@
 { lib, libb, builtinz, src, attrs }:
-rec
-{ usePureFromTOML = attrs.usePureFromTOML or true;
+let
+  usePureFromTOML = attrs.usePureFromTOML or true;
   readTOML = builtinz.readTOML usePureFromTOML;
 
+  # config used during build the prebuild and the final build
+  buildConfig =
+    {
       compressTarget = attrs.compressTarget or true;
+      doCheck = attrs.doCheck or true;
+      buildInputs = attrs.buildInputs or [];
+      removeReferencesToSrcFromDocs = attrs.removeReferencesToSrcFromDocs or true;
+      doDoc = attrs.doDoc or true;
+      #| Whether or not the rustdoc can fail the build
+      doDocFail = attrs.doDocFail or false;
 
+      release = attrs.release or true;
+
+      override = attrs.override or (x: x);
+
+      cargoBuild = attrs.cargoBuild or ''
+        cargo build "''${cargo_release}" -j $NIX_BUILD_CORES -Z unstable-options --out-dir out
+      '';
+
+      # The list of _all_ crates (incl. transitive dependencies) with name,
+      # version and sha256 of the crate
+      # Example:
+      #   [ { name = "wabt", version = "2.0.6", sha256 = "..." } ]
+      crateDependencies = libb.mkVersions buildPlanConfig.cargolock;
+    };
+
+  # config used when planning the builds
+  buildPlanConfig = rec
+    {
       # Whether we skip pre-building the deps
       isSingleStep = attrs.singleStep or false;
 
@@ -63,55 +90,22 @@ rec
       # The cargo lock
       cargolock = readTOML (src + "/Cargo.lock");
 
-  # The list of paths to Cargo.tomls. If this is a workspace, the paths
-  # are the members. Otherwise, there is a single path, ".".
-  cratePaths = lib.concatStringsSep "\n" wantedMembers;
-
       packageName = attrs.name or toplevelCargotoml.package.name or
         (if isWorkspace then "rust-workspace" else "rust-package");
 
       packageVersion = attrs.version or toplevelCargotoml.package.version or
         "unknown";
 
-  # The list of _all_ crates (incl. transitive dependencies) with name,
-  # version and sha256 of the crate
-  # Example:
-  #   [ { name = "wabt", version = "2.0.6", sha256 = "..." } ]
-  crateDependencies = libb.mkVersions cargolock;
-
-  preBuild = ''
-    # Cargo uses mtime, and we write `src/lib.rs` and `src/main.rs`in
-    # the dep build step, so make sure cargo rebuilds stuff
-    if [ -f src/lib.rs ] ; then touch src/lib.rs; fi
-    if [ -f src/main.rs ] ; then touch src/main.rs; fi
-  '';
-
-  cargoBuild = attrs.cargoBuild or ''
-    cargo build "''${cargo_release}" -j $NIX_BUILD_CORES -Z unstable-options --out-dir out
-  '';
       cargoTestCommands = attrs.cargoTestCommands or [
         ''cargo test "''${cargo_release}" -j $NIX_BUILD_CORES''
       ];
 
-  override = attrs.override or (x: x);
-
-  release = attrs.release or true;
-
       #| Whether or not to forward intermediate build artifacts to $out
       copyTarget = attrs.copyTarget or false;
 
-  #| Whether or not the rustdoc can fail the build
-  doDocFail = attrs.doDocFail or false;
-
-  doDoc = attrs.doDoc or true;
-
       copyBins = attrs.copyBins or true;
 
       copyDocsToSeparateOutput = attrs.copyDocsToSeparateOutput or true;
 
-  removeReferencesToSrcFromDocs = attrs.removeReferencesToSrcFromDocs or true;
-
-  doCheck = attrs.doCheck or true;
-
-  buildInputs = attrs.buildInputs or [];
-}
+    };
+in buildPlanConfig // { inherit buildConfig ; }

default.nix

@@ -44,9 +44,14 @@ let
       (defaultBuildAttrs //
         { pname = config.packageName;
           version = config.packageVersion;
-          inherit (config) cratePaths crateDependencies preBuild cargoBuild cargoTestCommands compressTarget override release copyTarget doDocFail doDoc copyBins copyDocsToSeparateOutput removeReferencesToSrcFromDocs doCheck buildInputs;
-        } //
-        (removeAttrs attrs [ "usePureFromTOML" "cargotomls" "singleStep" ]) //
+          preBuild = lib.optionalString (!config.isSingleStep) ''
+            # Cargo uses mtime, and we write `src/lib.rs` and `src/main.rs`in
+            # the dep build step, so make sure cargo rebuilds stuff
+            if [ -f src/lib.rs ] ; then touch src/lib.rs; fi
+            if [ -f src/main.rs ] ; then touch src/main.rs; fi
+          '';
+          inherit (config) cargoTestCommands copyTarget copyBins copyDocsToSeparateOutput ;
+        } // config.buildConfig //
         { builtDependencies = lib.optional (! config.isSingleStep)
             (
               import ./build.nix
@@ -63,10 +68,9 @@ let
               (defaultBuildAttrs //
                 { pname = "${config.packageName}-deps";
                   version = config.packageVersion;
-                  inherit (config) cratePaths crateDependencies cargoBuild compressTarget override release doDocFail doDoc removeReferencesToSrcFromDocs doCheck buildInputs;
-                } //
-              (removeAttrs attrs [ "usePureFromTOML" "cargotomls"  "singleStep"]) //
+                } // config.buildConfig //
               { preBuild = "";
+                # TODO: custom cargoTestCommands should not be needed here
                 cargoTestCommands = map (cmd: "${cmd} || true") config.cargoTestCommands;
                 copyTarget = true;
                 copyBins = false;