python3Packages.rembg: fix cuda build

pkgs/development/python-modules/rembg/default.nix

@@ -33,8 +33,12 @@
 
   # tests
   versionCheckHook,
+  pocl,
 
   withCli ? false,
+  config,
+  cudaSupport ? config.cudaSupport,
+  writableTmpDirAsHomeHook,
 }:
 
 let
@@ -100,8 +104,23 @@ buildPythonPackage (finalAttrs: {
   postInstall = lib.optionalString (!withCli) "rm -r $out/bin";
 
   # not running python tests, as they require network access
-  nativeCheckInputs = lib.optionals withCli [
+  nativeCheckInputs =
+    lib.optionals
+      (
+        withCli
+        # Crashes in the sandbox as no drivers are available
+        # opencl._cl.RuntimeError: no CL platforms available to ICD loader
+        && (!cudaSupport)
+      )
+      [
         versionCheckHook
+      ]
+    ++ lib.optionals cudaSupport [
+      # Provides a CPU-based OpenCL ICD so that pyopencl's module-level
+      # cl.create_some_context() succeeds without GPU hardware.
+      pocl
+      # pocl needs a writable $HOME for its kernel cache directory.
+      writableTmpDirAsHomeHook
     ];
   versionCheckKeepEnvironment = [
     # Otherwise, fail with: