buildRustPackage: factor out check phase to cargoCheckHook

API change:

`cargoParallelTestThreads` suggests that this attribute sets the
number of threads used during tests, while it is actually a boolean
option (use 1 thread or NIX_BUILD_CORES threads). In the hook, this
is replaced by a more canonical name `dontUseCargoParallelTests`.

pkgs/build-support/rust/default.nix

@@ -2,8 +2,8 @@
 , lib
 , buildPackages
 , cacert
-, cargo
 , cargoBuildHook
+, cargoCheckHook
 , cargoInstallHook
 , cargoSetupHook
 , fetchCargoTarball
@@ -42,7 +42,6 @@
 , cargoVendorDir ? null
 , checkType ? buildType
 , depsExtraArgs ? {}
-, cargoParallelTestThreads ? true
 
 # Toggles whether a custom sysroot is created when the target is a .json file.
 , __internal_dontAddSysroot ? false
@@ -105,8 +104,15 @@ stdenv.mkDerivation ((removeAttrs args ["depsExtraArgs"]) // lib.optionalAttrs u
 
   patchRegistryDeps = ./patch-registry-deps;
 
-  nativeBuildInputs = nativeBuildInputs ++
-    [ cacert git cargo cargoBuildHook cargoInstallHook cargoSetupHook rustc ];
+  nativeBuildInputs = nativeBuildInputs ++ [
+    cacert
+    git
+    cargoBuildHook
+    cargoCheckHook
+    cargoInstallHook
+    cargoSetupHook
+    rustc
+  ];
 
   buildInputs = buildInputs ++ lib.optional stdenv.hostPlatform.isMinGW windows.pthreads;
 
@@ -126,18 +132,6 @@ stdenv.mkDerivation ((removeAttrs args ["depsExtraArgs"]) // lib.optionalAttrs u
     runHook postConfigure
   '';
 
-  checkPhase = args.checkPhase or (let
-    argstr = "${lib.optionalString (checkType == "release") "--release"} --target ${target} --frozen";
-    threads = if cargoParallelTestThreads then "$NIX_BUILD_CORES" else "1";
-  in ''
-    ${lib.optionalString (buildAndTestSubdir != null) "pushd ${buildAndTestSubdir}"}
-    runHook preCheck
-    echo "Running cargo test ${argstr} -- ''${checkFlags} ''${checkFlagsArray+''${checkFlagsArray[@]}}"
-    cargo test -j $NIX_BUILD_CORES ${argstr} -- --test-threads=${threads} ''${checkFlags} ''${checkFlagsArray+"''${checkFlagsArray[@]}"}
-    runHook postCheck
-    ${lib.optionalString (buildAndTestSubdir != null) "popd"}
-  '');
-
   doCheck = args.doCheck or true;
 
   strictDeps = true;

pkgs/build-support/rust/hooks/cargo-check-hook.sh

@@ -0,0 +1,37 @@
+cargoCheckHook() {
+    echo "Executing cargoCheckHook"
+
+    runHook preCheck
+
+    if [[ -n "${buildAndTestSubdir-}" ]]; then
+        pushd "${buildAndTestSubdir}"
+    fi
+
+    if [[ -z ${dontUseCargoParallelTests-} ]]; then
+        threads=$NIX_BUILD_CORES
+    else
+        threads=1
+    fi
+
+    argstr="--${cargoBuildType} --target @rustTargetPlatformSpec@ --frozen";
+
+    (
+        set -x
+        cargo test \
+              -j $NIX_BUILD_CORES \
+              ${argstr} -- \
+              --test-threads=${threads} \
+              ${checkFlags} \
+              ${checkFlagsArray+"${checkFlagsArray[@]}"}
+    )
+
+    if [[ -n "${buildAndTestSubdir-}" ]]; then
+        popd
+    fi
+
+    echo "Finished cargoCheckHook"
+
+    runHook postCheck
+}
+
+checkPhase=cargoCheckHook

pkgs/build-support/rust/hooks/default.nix

@@ -36,6 +36,15 @@ in {
       };
     } ./cargo-build-hook.sh) {};
 
+  cargoCheckHook = callPackage ({ }:
+    makeSetupHook {
+      name = "cargo-check-hook.sh";
+      deps = [ cargo ];
+      substitutions = {
+        inherit rustTargetPlatformSpec;
+      };
+    } ./cargo-check-hook.sh) {};
+
   cargoInstallHook = callPackage ({ }:
     makeSetupHook {
       name = "cargo-install-hook.sh";