From 559a915f4211ee570da97d606bd6912b110fb737 Mon Sep 17 00:00:00 2001
From: Andrew Sinclair <asinclair@google.com>
Date: Thu, 10 Oct 2024 14:54:14 -0700
Subject: [PATCH] Use an aspect to validate the transitive deps of an
 android_feature_module.

This is prework before we filter out all dexes to ensure users aren't confused.

PiperOrigin-RevId: 684587452
Change-Id: Ie0b783725730ee17075120c52dc61f0ca0e60d40
---
 ...droid_feature_module_validation_aspect.bzl | 42 +++++++++++++++++++
 rules/android_application/attrs.bzl           |  3 +-
 2 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 rules/android_application/android_feature_module_validation_aspect.bzl

diff --git a/rules/android_application/android_feature_module_validation_aspect.bzl b/rules/android_application/android_feature_module_validation_aspect.bzl
new file mode 100644
index 000000000..f0ca1a507
--- /dev/null
+++ b/rules/android_application/android_feature_module_validation_aspect.bzl
@@ -0,0 +1,42 @@
+# 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.
+
+"""Aspect to validate the transitive dependencies of an android_feature_module."""
+_SRCS_DISALLOWED_EXTENSIONS = ["java", "kt", "srcjar"]
+
+_DISALLOWED_RULE_TYPES = ["java_import", "aar_import"]
+
+def _has_disallowed_srcs(srcs):
+    if not srcs:
+        return False
+    for src in srcs:
+        if src.extension in _SRCS_DISALLOWED_EXTENSIONS:
+            return True
+    return False
+
+def _impl(target, ctx):
+    if ctx.rule.kind in _DISALLOWED_RULE_TYPES:
+        fail("android_feature_module cannot transitively depend on {} rules".format(ctx.rule.kind))
+    srcs = getattr(ctx.rule.files, "srcs", [])
+    if _has_disallowed_srcs(srcs):
+        fail("android_feature_module cannot transitively depend on Java/Kotlin sources and {} has Java/Kotlin sources".format(target.label))
+    if getattr(ctx.rule.attr, "resource_files", False):
+        fail("android_feature_module cannot transitively depend on resource_files and {} has resource_files".format(target.label))
+    return []
+
+android_feature_module_validation_aspect = aspect(
+    implementation = _impl,
+    attr_aspects = ["deps", "exports"],
+    doc = "An aspect that validates the dependencies of an android_feature_module.",
+)
diff --git a/rules/android_application/attrs.bzl b/rules/android_application/attrs.bzl
index 0ba9c4bda..51d71700c 100644
--- a/rules/android_application/attrs.bzl
+++ b/rules/android_application/attrs.bzl
@@ -24,6 +24,7 @@ load(
     _attrs = "attrs",
 )
 load("//rules:visibility.bzl", "PROJECT_VISIBILITY")
+load(":android_feature_module_validation_aspect.bzl", "android_feature_module_validation_aspect")
 
 visibility(PROJECT_VISIBILITY)
 
@@ -102,7 +103,7 @@ ANDROID_APPLICATION_ATTRS = _attrs.add(
 )
 
 ANDROID_FEATURE_MODULE_ATTRS = dict(
-    binary = attr.label(),
+    binary = attr.label(aspects = [android_feature_module_validation_aspect]),
     feature_name = attr.string(),
     library = attr.label(
         allow_rules = ["android_library"],