Fix cquery-ing with cuda targets

cuda/defs.bzl

@@ -16,6 +16,7 @@ load(
     _use_cuda_toolchain = "use_cuda_toolchain",
 )
 load("//cuda/private:toolchain_configs/clang.bzl", _cuda_toolchain_config_clang = "cuda_toolchain_config")
+load("//cuda/private:toolchain_configs/dummy.bzl", _cuda_toolchain_config_dummy = "dummy_toolchain_config")
 load("//cuda/private:toolchain_configs/nvcc.bzl", _cuda_toolchain_config_nvcc = "cuda_toolchain_config")
 load("//cuda/private:toolchain_configs/nvcc_msvc.bzl", _cuda_toolchain_config_nvcc_msvc = "cuda_toolchain_config")
 
@@ -24,6 +25,7 @@ cuda_toolchain = _cuda_toolchain
 find_cuda_toolchain = _find_cuda_toolchain
 use_cuda_toolchain = _use_cuda_toolchain
 cuda_toolchain_config_clang = _cuda_toolchain_config_clang
+cuda_toolchain_config_dummy = _cuda_toolchain_config_dummy
 cuda_toolchain_config_nvcc_msvc = _cuda_toolchain_config_nvcc_msvc
 cuda_toolchain_config_nvcc = _cuda_toolchain_config_nvcc
 

cuda/private/repositories.bzl

@@ -190,13 +190,19 @@ def config_clang(repository_ctx, cuda, clang_path):
     }
     repository_ctx.template("toolchain/clang/BUILD", tpl_label, substitutions = substitutions, executable = False)
 
+def config_none(repository_ctx):
+    tpl_label = Label("//cuda:templates/BUILD.local_toolchain_none")
+    repository_ctx.template("toolchain/none/BUILD", tpl_label, executable = False)
+
 def _local_cuda_impl(repository_ctx):
     cuda = detect_cuda_toolkit(repository_ctx)
     config_cuda_toolkit_and_nvcc(repository_ctx, cuda)
 
     clang_path = detect_clang(repository_ctx)
     config_clang(repository_ctx, cuda, clang_path)
 
+    config_none(repository_ctx)
+
 local_cuda = repository_rule(
     implementation = _local_cuda_impl,
     attrs = {"toolkit_path": attr.string(mandatory = False)},

cuda/private/toolchain.bzl

@@ -86,4 +86,5 @@ User can setup their own toolchain if needed and ignore the detected ones by not
     native.register_toolchains(
         "@local_cuda//toolchain:nvcc-local-toolchain",
         "@local_cuda//toolchain/clang:clang-local-toolchain",
+        "@local_cuda//toolchain/none:none-local-toolchain",
     )

cuda/private/toolchain_configs/dummy.bzl

@@ -0,0 +1,4 @@
+def _dummy_toolchain_config_impl(_ctx):
+    return [platform_common.ToolchainInfo()]
+
+dummy_toolchain_config = rule(_dummy_toolchain_config_impl, attrs = {})

cuda/templates/BUILD.local_toolchain_none

@@ -0,0 +1,16 @@
+load("@rules_cuda//cuda:defs.bzl", "cuda_toolchain_config_dummy")
+
+config_setting(
+    name = "cuda_is_disabled",
+    flag_values = {"@rules_cuda//cuda:enable": "False"},
+)
+
+cuda_toolchain_config_dummy(name = "dummy-local")
+
+toolchain(
+    name = "none-local-toolchain",
+    target_settings = [":cuda_is_disabled"],
+    toolchain = ":dummy-local",
+    toolchain_type = "@rules_cuda//cuda:toolchain_type",
+    visibility = ["//visibility:public"],
+)

examples/if_cuda/BUILD.bazel

@@ -4,6 +4,10 @@ cuda_library(
     name = "kernel",
     srcs = ["kernel.cu"],
     hdrs = ["kernel.h"],
+    target_compatible_with = select({
+        "@rules_cuda//cuda:is_enabled": [],
+        "//conditions:default": ["@platforms//:incompatible"],
+    }),
 )
 
 cc_binary(