From 991cdf09a92386d22de007280d72b0aca2fb4c5f Mon Sep 17 00:00:00 2001
From: Googler <noreply@google.com>
Date: Mon, 25 Mar 2024 23:43:33 -0700
Subject: [PATCH] Implement provides in rule based toolchain.

BEGIN_PUBLIC
Implement provides in rule based toolchain.
END_PUBLIC

PiperOrigin-RevId: 619082926
Change-Id: I938640981bd10f0e3d41402d211672a45264df1a
---
 cc/toolchains/mutually_exclusive_category.bzl | 29 +++++++++++++++++++
 tests/rule_based_toolchain/features/BUILD     | 10 ++++++-
 .../features/features_test.bzl                | 14 +++++----
 3 files changed, 46 insertions(+), 7 deletions(-)
 create mode 100644 cc/toolchains/mutually_exclusive_category.bzl

diff --git a/cc/toolchains/mutually_exclusive_category.bzl b/cc/toolchains/mutually_exclusive_category.bzl
new file mode 100644
index 0000000..9920290
--- /dev/null
+++ b/cc/toolchains/mutually_exclusive_category.bzl
@@ -0,0 +1,29 @@
+# Copyright 2024 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.
+"""Rule for mutually exclusive categories in the rule based toolchain."""
+
+load(":cc_toolchain_info.bzl", "MutuallyExclusiveCategoryInfo")
+
+def _cc_mutually_exclusive_category_impl(ctx):
+    return [MutuallyExclusiveCategoryInfo(
+        label = ctx.label,
+        name = str(ctx.label),
+    )]
+
+cc_mutually_exclusive_category = rule(
+    implementation = _cc_mutually_exclusive_category_impl,
+    doc = "A category of features, for which only one can be enabled",
+    attrs = {},
+    provides = [MutuallyExclusiveCategoryInfo],
+)
diff --git a/tests/rule_based_toolchain/features/BUILD b/tests/rule_based_toolchain/features/BUILD
index 95f67aa..cc3c0c7 100644
--- a/tests/rule_based_toolchain/features/BUILD
+++ b/tests/rule_based_toolchain/features/BUILD
@@ -3,6 +3,7 @@ load("//cc/toolchains:args.bzl", "cc_args")
 load("//cc/toolchains:feature.bzl", "cc_feature")
 load("//cc/toolchains:feature_constraint.bzl", "cc_feature_constraint")
 load("//cc/toolchains:feature_set.bzl", "cc_feature_set")
+load("//cc/toolchains:mutually_exclusive_category.bzl", "cc_mutually_exclusive_category")
 load("//cc/toolchains/impl:external_feature.bzl", "cc_external_feature")
 load("//tests/rule_based_toolchain:analysis_test_suite.bzl", "analysis_test_suite")
 load(":features_test.bzl", "TARGETS", "TESTS")
@@ -59,13 +60,20 @@ util.helper_target(
     implies = [":simple"],
 )
 
+cc_mutually_exclusive_category(
+    name = "category",
+)
+
 util.helper_target(
     cc_feature,
     name = "mutual_exclusion_feature",
     args = [":c_compile"],
     enabled = True,
     feature_name = "mutual_exclusion",
-    mutually_exclusive = [":simple"],
+    mutually_exclusive = [
+        ":simple",
+        ":category",
+    ],
 )
 
 util.helper_target(
diff --git a/tests/rule_based_toolchain/features/features_test.bzl b/tests/rule_based_toolchain/features/features_test.bzl
index f0b15fd..2345cd7 100644
--- a/tests/rule_based_toolchain/features/features_test.bzl
+++ b/tests/rule_based_toolchain/features/features_test.bzl
@@ -89,6 +89,7 @@ def _feature_collects_mutual_exclusion_test(env, targets):
         FeatureInfo,
     ).mutually_exclusive().contains_exactly([
         targets.simple.label,
+        targets.category.label,
     ])
 
 def _feature_set_collects_features_test(env, targets):
@@ -144,17 +145,18 @@ def _feature_can_be_overridden_test(env, targets):
     overrides.overrides().some().label().equals(targets.builtin_feature.label)
 
 TARGETS = [
+    ":builtin_feature",
     ":c_compile",
-    ":simple",
-    ":simple2",
+    ":category",
+    ":direct_constraint",
     ":feature_set",
-    ":requires",
     ":implies",
     ":mutual_exclusion_feature",
-    ":direct_constraint",
-    ":transitive_constraint",
-    ":builtin_feature",
     ":overrides",
+    ":requires",
+    ":simple",
+    ":simple2",
+    ":transitive_constraint",
 ]
 
 # @unsorted-dict-items