Merge master into staging-next

3 files changed, 26 insertions, 8 deletions

diff --git a/pkgs/build-support/agda/default.nix b/pkgs/build-support/agda/default.nix
index 16fe748c3e5c..3e5d8e6c384c 100644
--- a/pkgs/build-support/agda/default.nix
+++ b/pkgs/build-support/agda/default.nix
@@ -1,6 +1,4 @@
 # Builder for Agda packages. Mostly inspired by the cabal builder.
-#
-# Contact: stdenv.lib.maintainers.fuuzetsu
 
 { stdenv, Agda, glibcLocales
 , writeShellScriptBin
diff --git a/pkgs/build-support/trivial-builders.nix b/pkgs/build-support/trivial-builders.nix
index 55df09121b42..5210b7d7ba20 100644
--- a/pkgs/build-support/trivial-builders.nix
+++ b/pkgs/build-support/trivial-builders.nix
@@ -2,11 +2,16 @@
 
 let
 
-  runCommand' = stdenv: name: env: buildCommand:
+  runCommand' = runLocal: stdenv: name: env: buildCommand:
     stdenv.mkDerivation ({
       inherit name buildCommand;
       passAsFile = [ "buildCommand" ];
-    } // env);
+    }
+    // (lib.optionalAttrs runLocal {
+          preferLocalBuild = true;
+          allowSubstitutes = false;
+       })
+    // env);
 
 in
 
@@ -21,11 +26,27 @@ rec {
   * runCommand "name" {envVariable = true;} ''echo hello > $out''
   * runCommandNoCC "name" {envVariable = true;} ''echo hello > $out'' # equivalent to prior
   * runCommandCC "name" {} ''gcc -o myfile myfile.c; cp myfile $out'';
+  *
+  * The `*Local` variants force a derivation to be built locally,
+  * it is not substituted.
+  *
+  * This is intended for very cheap commands (<1s execution time).
+  * It saves on the network roundrip and can speed up a build.
+  *
+  * It is the same as adding the special fields
+  * `preferLocalBuild = true;`
+  * `allowSubstitutes = false;`
+  * to a derivation’s attributes.
   */
   runCommand = runCommandNoCC;
-  runCommandNoCC = runCommand' stdenvNoCC;
-  runCommandCC = runCommand' stdenv;
+  runCommandLocal = runCommandNoCCLocal;
+
+  runCommandNoCC = runCommand' false stdenvNoCC;
+  runCommandNoCCLocal = runCommand' true stdenvNoCC;
 
+  runCommandCC = runCommand' false stdenv;
+  # `runCommandCCLocal` left out on purpose.
+  # We shouldn’t force the user to have a cc in scope.
 
   /* Writes a text file to the nix store.
    * The contents of text is added to the file in the store.
diff --git a/pkgs/build-support/vm/windows/default.nix b/pkgs/build-support/vm/windows/default.nix
index 48ee2713d1f6..309241c36dee 100644
--- a/pkgs/build-support/vm/windows/default.nix
+++ b/pkgs/build-support/vm/windows/default.nix
@@ -20,8 +20,7 @@ let
   '';
 
 in {
-  runInWindowsVM = drv: let
-  in pkgs.lib.overrideDerivation drv (attrs: let
+  runInWindowsVM = drv: pkgs.lib.overrideDerivation drv (attrs: let
     bootstrap = bootstrapper attrs.windowsImage;
   in {
     requiredSystemFeatures = [ "kvm" ];