Add test for objc_library modules interop

swift/internal/compiling.bzl

@@ -213,6 +213,37 @@ def create_compilation_context(defines, srcs, transitive_modules):
         swiftmodules = tuple(swiftmodules),
     )
 
+def _clang_module_map_info(swift_infos):
+    """Returns Clang module maps and include dirs from Swift deps."""
+
+    module_maps = []
+    include_dirs = []
+    seen_module_maps = {}
+    for swift_info in swift_infos:
+        for module in swift_info.direct_modules:
+            clang_module = module.clang
+            if not clang_module:
+                continue
+
+            module_map = clang_module.module_map
+            if type(module_map) != "File":
+                continue
+
+            if module_map.path in seen_module_maps:
+                continue
+
+            seen_module_maps[module_map.path] = None
+            module_maps.append(module_map)
+            include_dirs.append(module_map.dirname)
+
+    if not module_maps:
+        return None
+
+    return struct(
+        include_dirs = include_dirs,
+        module_maps = module_maps,
+    )
+
 def compile_module_interface(
         *,
         actions,
@@ -698,6 +729,13 @@ def compile(
         cc_info.compilation_context
         for cc_info in cc_infos
     ]
+
+    generated_header_module_map_info = None
+    if generated_header_name:
+        generated_header_module_map_info = _clang_module_map_info(
+            generated_module_deps_swift_infos,
+        )
+
     merged_cc_info = cc_common.merge_cc_infos(
         cc_infos = cc_infos + private_cc_infos +
                    implicit_cc_infos,
@@ -913,6 +951,10 @@ to use swift_common.compile(include_dev_srch_paths = ...) instead.\
     else:
         includes = []
 
+    if generated_header_module_map_info:
+        public_hdrs.extend(generated_header_module_map_info.module_maps)
+        includes.extend(generated_header_module_map_info.include_dirs)
+
     module_context = create_swift_module_context(
         name = module_name,
         clang = create_clang_module_inputs(

test/fixtures/generated_header/BUILD

@@ -1,3 +1,8 @@
+load("@rules_cc//cc:objc_library.bzl", "objc_library")
+load(
+    "//swift:swift_interop_hint.bzl",
+    "swift_interop_hint",
+)
 load(
     "//swift:swift_library.bzl",
     "swift_library",
@@ -55,3 +60,37 @@ swift_library(
     generates_header = False,
     tags = FIXTURE_TAGS,
 )
+
+objc_library(
+    name = "c_dependency",
+    srcs = ["CDependency.m"],
+    hdrs = ["CDependency.h"],
+    aspect_hints = [":c_dependency_hint"],
+    tags = FIXTURE_TAGS,
+    target_compatible_with = ["@platforms//os:macos"],
+    deps = ["@system_sdk//:Foundation"],
+)
+
+swift_interop_hint(
+    name = "c_dependency_hint",
+    module_name = "GeneratedHeaderCDependency",
+    tags = FIXTURE_TAGS,
+)
+
+swift_library(
+    name = "generated_header_with_c_dep",
+    srcs = ["UsesCDependency.swift"],
+    generates_header = True,
+    tags = FIXTURE_TAGS,
+    target_compatible_with = ["@platforms//os:macos"],
+    deps = [":c_dependency"],
+)
+
+objc_library(
+    name = "objc_consumer_of_generated_header",
+    srcs = ["ObjcConsumer.m"],
+    enable_modules = True,
+    tags = FIXTURE_TAGS,
+    target_compatible_with = ["@platforms//os:macos"],
+    deps = [":generated_header_with_c_dep"],
+)

test/fixtures/generated_header/CDependency.h

@@ -0,0 +1,18 @@
+// Copyright 2026 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+@interface GHCBox<ObjectType> : NSObject
+@end

test/fixtures/generated_header/CDependency.m

@@ -0,0 +1,18 @@
+// Copyright 2026 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "test/fixtures/generated_header/CDependency.h"
+
+@implementation GHCBox
+@end

test/fixtures/generated_header/ObjcConsumer.m

@@ -0,0 +1,19 @@
+// Copyright 2026 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "test/fixtures/generated_header/generated_header_with_c_dep-Swift.h"
+
+void useGeneratedHeader(GHUsesCDependency *object, NSObject *value) {
+  (void)[object box:value];
+}

test/fixtures/generated_header/UsesCDependency.swift

@@ -0,0 +1,23 @@
+// Copyright 2026 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+import GeneratedHeaderCDependency
+
+@objc(GHUsesCDependency)
+public class UsesCDependency: NSObject {
+  @objc public func box(_ value: NSObject) -> GHCBox<NSObject> {
+    fatalError("not implemented")
+  }
+}

test/generated_header_tests.bzl

@@ -14,6 +14,7 @@
 
 """Tests for `swift_library.generated_header`."""
 
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 load(
     "//test/rules:action_command_line_test.bzl",
     "make_action_command_line_test_rule",
@@ -108,6 +109,15 @@ def generated_header_test_suite(name, tags = []):
         target_compatible_with = ["@platforms//os:macos"],
     )
 
+    build_test(
+        name = "{}_objc_consumer_finds_generated_header_imports".format(name),
+        targets = [
+            "//test/fixtures/generated_header:objc_consumer_of_generated_header",
+        ],
+        tags = all_tags,
+        target_compatible_with = ["@platforms//os:macos"],
+    )
+
     # Verify that no generated header is created if the target doesn't request
     # it.
     provider_test(