From e1a5823f8d0660480d6a90fa83fabffe0beb0eae Mon Sep 17 00:00:00 2001
From: Aaron Jheng <wentworth@outlook.com>
Date: Thu, 11 Jun 2026 17:31:36 +0800
Subject: [PATCH] diffoscope: fix hdf5 tools on Darwin

---
 pkgs/by-name/di/diffoscope/package.nix | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/pkgs/by-name/di/diffoscope/package.nix b/pkgs/by-name/di/diffoscope/package.nix
index 20e30df4e5ea..6050432bcd0e 100644
--- a/pkgs/by-name/di/diffoscope/package.nix
+++ b/pkgs/by-name/di/diffoscope/package.nix
@@ -273,6 +273,20 @@ python.pkgs.buildPythonApplication rec {
     "-vv"
   ];
 
+  preCheck = lib.optionalString (enableBloat && stdenv.hostPlatform.isDarwin) ''
+    # h5dump is in hdf5's bin output, but its dylibs are in the out output.
+    export DYLD_LIBRARY_PATH="${lib.makeLibraryPath [ hdf5 ]}''${DYLD_LIBRARY_PATH:+:''${DYLD_LIBRARY_PATH}}"
+  '';
+
+  makeWrapperArgs = lib.optionals enableBloat (
+    [
+      "--prefix PATH : ${lib.makeBinPath [ hdf5 ]}"
+    ]
+    ++ lib.optionals stdenv.hostPlatform.isDarwin [
+      "--prefix DYLD_LIBRARY_PATH : ${lib.makeLibraryPath [ hdf5 ]}"
+    ]
+  );
+
   postInstall = ''
     make -C doc
     installManPage doc/diffoscope.1