Vendor dependencies

Let's see how I like this workflow.

vendor/cxx/tools/buck/prelude/android/android_library.bzl

@@ -0,0 +1,92 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under both the MIT license found in the
+# LICENSE-MIT file in the root directory of this source tree and the Apache
+# License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+# of this source tree.
+
+load(
+    "@prelude//android:android_providers.bzl",
+    "AndroidLibraryIntellijInfo",
+    "AndroidResourceInfo",
+    "merge_android_packageable_info",
+    "merge_exported_android_resource_info",
+)
+load("@prelude//android:android_toolchain.bzl", "AndroidToolchainInfo")
+load("@prelude//android:r_dot_java.bzl", "get_dummy_r_dot_java")
+load("@prelude//java:java_library.bzl", "build_java_library")
+load("@prelude//java:java_providers.bzl", "create_native_providers", "to_list")
+load("@prelude//java:java_toolchain.bzl", "JavaToolchainInfo")
+load("@prelude//kotlin:kotlin_library.bzl", "build_kotlin_library")
+
+def android_library_impl(ctx: "context") -> ["provider"]:
+    packaging_deps = ctx.attrs.deps + (ctx.attrs.deps_query or []) + ctx.attrs.exported_deps + ctx.attrs.runtime_deps
+    if ctx.attrs._build_only_native_code:
+        shared_library_info, cxx_resource_info = create_native_providers(ctx.actions, ctx.label, packaging_deps)
+        return [
+            shared_library_info,
+            cxx_resource_info,
+            # Add an unused default output in case this target is used as an attr.source() anywhere.
+            DefaultInfo(default_outputs = [ctx.actions.write("unused.jar", [])]),
+        ]
+
+    java_providers, android_library_intellij_info = build_android_library(ctx)
+    android_providers = [android_library_intellij_info] if android_library_intellij_info else []
+
+    return to_list(java_providers) + [
+        merge_android_packageable_info(
+            ctx.label,
+            ctx.actions,
+            packaging_deps,
+            manifest = ctx.attrs.manifest,
+        ),
+        merge_exported_android_resource_info(ctx.attrs.exported_deps),
+    ] + android_providers
+
+def build_android_library(
+        ctx: "context") -> ("JavaProviders", [AndroidLibraryIntellijInfo.type, None]):
+    java_toolchain = ctx.attrs._java_toolchain[JavaToolchainInfo]
+    bootclasspath_entries = [] + ctx.attrs._android_toolchain[AndroidToolchainInfo].android_bootclasspath
+    additional_classpath_entries = []
+    android_library_intellij_info = None
+
+    dummy_r_dot_java = _get_dummy_r_dot_java(ctx, java_toolchain)
+    if dummy_r_dot_java:
+        additional_classpath_entries.append(dummy_r_dot_java)
+        android_library_intellij_info = AndroidLibraryIntellijInfo(
+            dummy_r_dot_java = dummy_r_dot_java,
+        )
+
+    if ctx.attrs.language != None and ctx.attrs.language.lower() == "kotlin":
+        return build_kotlin_library(
+            ctx,
+            additional_classpath_entries = additional_classpath_entries,
+            bootclasspath_entries = bootclasspath_entries,
+        ), android_library_intellij_info
+    else:
+        return build_java_library(
+            ctx,
+            ctx.attrs.srcs,
+            additional_classpath_entries = additional_classpath_entries,
+            bootclasspath_entries = bootclasspath_entries,
+        ), android_library_intellij_info
+
+def _get_dummy_r_dot_java(
+        ctx: "context",
+        java_toolchain: "JavaToolchainInfo") -> ["artifact", None]:
+    android_resources = [resource for resource in filter(None, [
+        x.get(AndroidResourceInfo)
+        for x in ctx.attrs.deps + (ctx.attrs.deps_query or []) + ctx.attrs.provided_deps + (getattr(ctx.attrs, "provided_deps_query", []) or [])
+    ]) if resource.res != None]
+    if len(android_resources) == 0:
+        return None
+
+    dummy_r_dot_java_library_info = get_dummy_r_dot_java(
+        ctx,
+        ctx.attrs._android_toolchain[AndroidToolchainInfo].merge_android_resources[RunInfo],
+        java_toolchain,
+        dedupe(android_resources),
+        ctx.attrs.resource_union_package,
+    )
+
+    return dummy_r_dot_java_library_info.library_output.abi