From 34d0c0cef5e3a3307653159018727ea32d8bde30 Mon Sep 17 00:00:00 2001
From: Marc Scholten <marc@digitallyinduced.com>
Date: Sun, 16 Nov 2025 12:15:24 -0800
Subject: [PATCH] haskellPackages.mkDerivation: pass -j to haddock

---
 pkgs/development/haskell-modules/generic-builder.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index 5cebe4aec5d0..4ff85fe5d540 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -805,6 +805,7 @@ lib.fix (
             ${optionalString doHoogle "--hoogle"} \
             ${optionalString doHaddockQuickjump "--quickjump"} \
             ${optionalString (isLibrary && hyperlinkSource) "--hyperlink-source"} \
+            ${optionalString enableParallelBuilding "--haddock-option=-j$NIX_BUILD_CORES"} \
             ${lib.concatStringsSep " " haddockFlags}
         ''}
         runHook postHaddock