Correctly exclude both the actual and virtual header when using `swif…

…t_interop_hint.exclude_hdrs` on a `cc_library` that has `include_prefix` and/or `strip_include_prefix` set.

PiperOrigin-RevId: 412917671

swift/internal/swift_clang_module_aspect.bzl

@@ -14,6 +14,7 @@
 
 """Propagates unified `SwiftInfo` providers for C/Objective-C targets."""
 
+load("@bazel_skylib//lib:sets.bzl", "sets")
 load(":attrs.bzl", "swift_toolchain_attrs")
 load(":compiling.bzl", "derive_module_name", "precompile_clang_module")
 load(":derived_files.bzl", "derived_files")
@@ -188,7 +189,42 @@ def create_swift_interop_info(
         unsupported_features = unsupported_features,
     )
 
+def _compute_all_excluded_headers(*, exclude_headers, target):
+    """Returns the full set of headers to exclude for a target.
+
+    This function specifically handles the `cc_library` logic around the
+    `include_prefix` and `strip_include_prefix` attributes, which cause Bazel to
+    create a virtual header (symlink) for every public header in the target. For
+    the generated module map to be created, we must exclude both the actual
+    header file and the symlink.
+
+    Args:
+        exclude_headers: A list of `File`s representing headers that should be
+            excluded from the module.
+        target: The target to which the aspect is being applied.
+
+    Returns:
+        A list containing the complete set of headers that should be excluded,
+        including any virtual header symlinks that match a real header in the
+        excluded headers list passed into the function.
+    """
+    exclude_headers_set = sets.make(exclude_headers)
+    virtual_exclude_headers = []
+
+    for action in target.actions:
+        if action.mnemonic != "Symlink":
+            continue
+
+        original_header = action.inputs.to_list()[0]
+        virtual_header = action.outputs.to_list()[0]
+
+        if sets.contains(exclude_headers_set, original_header):
+            virtual_exclude_headers.append(virtual_header)
+
+    return exclude_headers + virtual_exclude_headers
+
 def _generate_module_map(
+        *,
         actions,
         compilation_context,
         dependent_module_names,
@@ -234,17 +270,32 @@ def _generate_module_map(
     else:
         private_headers = compilation_context.direct_private_headers
 
-    module_map_file = derived_files.module_map(
-        actions = actions,
-        target_name = target.label.name,
-    )
-
     # Sort dependent module names and the headers to ensure a deterministic
     # order in the output file, in the event the compilation context would ever
     # change this on us. For files, use the execution path as the sorting key.
     def _path_sorting_key(file):
         return file.path
 
+    public_headers = sorted(
+        compilation_context.direct_public_headers,
+        key = _path_sorting_key,
+    )
+
+    module_map_file = derived_files.module_map(
+        actions = actions,
+        target_name = target.label.name,
+    )
+
+    if exclude_headers:
+        # If we're excluding headers from the module map, make sure to pick up
+        # any virtual header symlinks that might be created, for example, by a
+        # `cc_library` using the `include_prefix` and/or `strip_include_prefix`
+        # attributes.
+        exclude_headers = _compute_all_excluded_headers(
+            exclude_headers = exclude_headers,
+            target = target,
+        )
+
     write_module_map(
         actions = actions,
         dependent_module_names = sorted(dependent_module_names),
@@ -253,10 +304,7 @@ def _generate_module_map(
         module_map_file = module_map_file,
         module_name = module_name,
         private_headers = sorted(private_headers, key = _path_sorting_key),
-        public_headers = sorted(
-            compilation_context.direct_public_headers,
-            key = _path_sorting_key,
-        ),
+        public_headers = public_headers,
         public_textual_headers = sorted(
             compilation_context.direct_textual_headers,
             key = _path_sorting_key,

test/BUILD

@@ -1,4 +1,5 @@
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
+load(":cc_library_tests.bzl", "cc_library_test_suite")
 load(":debug_settings_tests.bzl", "debug_settings_test_suite")
 load(":generated_header_tests.bzl", "generated_header_test_suite")
 load(":interop_hints_tests.bzl", "interop_hints_test_suite")
@@ -7,6 +8,8 @@ load(":swift_through_non_swift_tests.bzl", "swift_through_non_swift_test_suite")
 
 licenses(["notice"])
 
+cc_library_test_suite()
+
 debug_settings_test_suite()
 
 generated_header_test_suite()
@@ -27,5 +30,6 @@ bzl_library(
     deps = [
         "//test/fixtures:starlark_tests_bzls",
         "//test/rules:starlark_tests_bzls",
+        "@bazel_skylib//rules:build_test",
     ],
 )

test/cc_library_tests.bzl

@@ -0,0 +1,53 @@
+# Copyright 2021 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.
+
+"""Tests for interoperability with `cc_library`-specific features."""
+
+load(
+    "@bazel_skylib//rules:build_test.bzl",
+    "build_test",
+)
+
+def cc_library_test_suite():
+    """Test suite for interoperability with `cc_library`-specific features."""
+    name = "cc_library"
+
+    # Verify that Swift can import a `cc_library` that uses `include_prefix`,
+    # `strip_include_prefix`, or both.
+    build_test(
+        name = "{}_swift_imports_cc_library_with_include_prefix_manipulation".format(name),
+        targets = [
+            "@build_bazel_rules_swift//test/fixtures/cc_library:import_prefix_and_strip_prefix",
+            "@build_bazel_rules_swift//test/fixtures/cc_library:import_prefix_only",
+            "@build_bazel_rules_swift//test/fixtures/cc_library:import_strip_prefix_only",
+        ],
+        tags = [name],
+    )
+
+    # Verify that `swift_interop_hint.exclude_hdrs` correctly excludes headers
+    # from a `cc_library` that uses `include_prefix` and/or
+    # `strip_include_prefix` (i.e., both the real header and the virtual header
+    # are excluded).
+    build_test(
+        name = "{}_swift_interop_hint_excludes_headers_with_include_prefix_manipulation".format(name),
+        targets = [
+            "@build_bazel_rules_swift//test/fixtures/cc_library:import_prefix_and_strip_prefix_with_exclusion",
+        ],
+        tags = [name],
+    )
+
+    native.test_suite(
+        name = name,
+        tags = [name],
+    )

test/fixtures/cc_library/BUILD

@@ -0,0 +1,95 @@
+load(
+    "//swift:swift.bzl",
+    "swift_interop_hint",
+    "swift_library",
+)
+load("//test/fixtures:common.bzl", "FIXTURE_TAGS")
+
+package(
+    default_visibility = ["//test:__subpackages__"],
+)
+
+licenses(["notice"])
+
+###############################################################################
+# Fixtures for testing complex `cc_library` interop cases.
+
+cc_library(
+    name = "prefix_only",
+    hdrs = [
+        "header.h",
+        "header_prefix_only.h",
+    ],
+    aspect_hints = ["//swift:auto_module"],
+    include_prefix = "some/prefix",
+    tags = FIXTURE_TAGS,
+)
+
+cc_library(
+    name = "strip_prefix_only",
+    hdrs = [
+        "header.h",
+        "header_strip_prefix_only.h",
+    ],
+    aspect_hints = ["//swift:auto_module"],
+    strip_include_prefix = "//test",
+    tags = FIXTURE_TAGS,
+)
+
+cc_library(
+    name = "prefix_and_strip_prefix",
+    hdrs = [
+        "header.h",
+        "header_prefix_and_strip_prefix.h",
+    ],
+    aspect_hints = ["//swift:auto_module"],
+    include_prefix = "some/prefix",
+    strip_include_prefix = "//test",
+    tags = FIXTURE_TAGS,
+)
+
+cc_library(
+    name = "prefix_and_strip_prefix_with_exclusion",
+    hdrs = [
+        "header.h",
+        "header_with_error.h",
+    ],
+    aspect_hints = [":prefix_and_strip_prefix_with_exclusion_swift_hint"],
+    include_prefix = "some/prefix",
+    strip_include_prefix = "//test",
+    tags = FIXTURE_TAGS,
+)
+
+swift_interop_hint(
+    name = "prefix_and_strip_prefix_with_exclusion_swift_hint",
+    exclude_hdrs = ["header_with_error.h"],
+    tags = FIXTURE_TAGS,
+)
+
+swift_library(
+    name = "import_prefix_only",
+    srcs = ["ImportPrefixOnly.swift"],
+    tags = FIXTURE_TAGS,
+    deps = [":prefix_only"],
+)
+
+swift_library(
+    name = "import_strip_prefix_only",
+    srcs = ["ImportStripPrefixOnly.swift"],
+    tags = FIXTURE_TAGS,
+    deps = [":strip_prefix_only"],
+)
+
+swift_library(
+    name = "import_prefix_and_strip_prefix",
+    srcs = ["ImportPrefixAndStripPrefix.swift"],
+    tags = FIXTURE_TAGS,
+    deps = [":prefix_and_strip_prefix"],
+)
+
+swift_library(
+    name = "import_prefix_and_strip_prefix_with_exclusion",
+    srcs = ["ImportPrefixAndStripPrefixWithExclusion.swift"],
+    tags = FIXTURE_TAGS,
+    deps = [":prefix_and_strip_prefix_with_exclusion"],
+)

test/fixtures/cc_library/ImportPrefixAndStripPrefix.swift

@@ -0,0 +1,3 @@
+import test_fixtures_cc_library_prefix_and_strip_prefix
+
+func f(_ x: some_structure) {}

test/fixtures/cc_library/ImportPrefixAndStripPrefixWithExclusion.swift

@@ -0,0 +1,3 @@
+import test_fixtures_cc_library_prefix_and_strip_prefix_with_exclusion
+
+func f(_ x: some_structure) {}

test/fixtures/cc_library/ImportPrefixOnly.swift

@@ -0,0 +1,3 @@
+import test_fixtures_cc_library_prefix_only
+
+func f(_ x: some_structure) {}

test/fixtures/cc_library/ImportStripPrefixOnly.swift

@@ -0,0 +1,3 @@
+import test_fixtures_cc_library_strip_prefix_only
+
+func f(_ x: some_structure) {}

test/fixtures/cc_library/header.h

@@ -0,0 +1,8 @@
+#ifndef RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_H_
+#define RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_H_
+
+typedef struct {
+  int field;
+} some_structure;
+
+#endif  // RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_H_

test/fixtures/cc_library/header_prefix_and_strip_prefix.h

@@ -0,0 +1,6 @@
+#ifndef RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_PREFIX_AND_STRIP_PREFIX_H_
+#define RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_PREFIX_AND_STRIP_PREFIX_H_
+
+#include "some/prefix/fixtures/cc_library/header.h"
+
+#endif  // RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_PREFIX_AND_STRIP_PREFIX_H_

test/fixtures/cc_library/header_prefix_only.h

@@ -0,0 +1,6 @@
+#ifndef RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_PREFIX_ONLY_H_
+#define RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_PREFIX_ONLY_H_
+
+#include "some/prefix/header.h"
+
+#endif  // RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_PREFIX_ONLY_H_

test/fixtures/cc_library/header_strip_prefix_only.h

@@ -0,0 +1,6 @@
+#ifndef RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_STRIP_PREFIX_ONLY_H_
+#define RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_STRIP_PREFIX_ONLY_H_
+
+#include "fixtures/cc_library/header.h"
+
+#endif  // RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_STRIP_PREFIX_ONLY_H_

test/fixtures/cc_library/header_with_error.h

@@ -0,0 +1,6 @@
+#ifndef RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_WITH_ERROR_H_
+#define RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_WITH_ERROR_H_
+
+#error This should never get processed.
+
+#endif  // RULES_SWIFT_TEST_FIXTURES_CC_LIBRARY_HEADER_WITH_ERROR_H_