Export default apex version from updatable_modules.go to Bazel's

apex_toolchain through soong_injection.

This is necessary to keep both Bazel and Soong in sync.

Test: presubmit
Bug: 238723069
Fixes: 238153998

Change-Id: Ibf4a8ed91d358dc7800c10e4112485a52f0606bb

apex/Android.bp

@@ -26,6 +26,7 @@ bootstrap_go_package {
         "apex_sdk_member.go",
         "apex_singleton.go",
         "builder.go",
+        "bp2build.go",
         "deapexer.go",
         "key.go",
         "prebuilt.go",

apex/bp2build.go

@@ -0,0 +1,30 @@
+// Copyright (C) 2022 The Android Open Source Project
+//
+// 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.
+package apex
+
+import (
+	"android/soong/android"
+	"strings"
+)
+
+// This file contains the bp2build integration for the apex package.
+
+// Export constants as Starlark using bp2build to Bazel.
+func BazelApexToolchainVars() string {
+	content := []string{
+		"# GENERATED BY SOONG. DO NOT EDIT.",
+		"default_manifest_version = " + android.DefaultUpdatableModuleVersion, // constants.go is different in every branch.
+	}
+	return strings.Join(content, "\n")
+}

bp2build/conversion.go

@@ -10,6 +10,8 @@ import (
 	cc_config "android/soong/cc/config"
 	java_config "android/soong/java/config"
 
+	"android/soong/apex"
+
 	"github.com/google/blueprint/proptools"
 )
 
@@ -28,6 +30,9 @@ func CreateSoongInjectionFiles(cfg android.Config, metrics CodegenMetrics) []Baz
 	files = append(files, newFile("java_toolchain", GeneratedBuildFileName, "")) // Creates a //java_toolchain package.
 	files = append(files, newFile("java_toolchain", "constants.bzl", java_config.BazelJavaToolchainVars(cfg)))
 
+	files = append(files, newFile("apex_toolchain", GeneratedBuildFileName, "")) // Creates a //apex_toolchain package.
+	files = append(files, newFile("apex_toolchain", "constants.bzl", apex.BazelApexToolchainVars()))
+
 	files = append(files, newFile("metrics", "converted_modules.txt", strings.Join(metrics.convertedModules, "\n")))
 
 	files = append(files, newFile("product_config", "soong_config_variables.bzl", cfg.Bp2buildSoongConfigDefinitions.String()))

bp2build/conversion_test.go

@@ -103,6 +103,14 @@ func TestCreateBazelFiles_Bp2Build_CreatesDefaultFiles(t *testing.T) {
 			dir:      "java_toolchain",
 			basename: "constants.bzl",
 		},
+		{
+			dir:      "apex_toolchain",
+			basename: GeneratedBuildFileName,
+		},
+		{
+			dir:      "apex_toolchain",
+			basename: "constants.bzl",
+		},
 		{
 			dir:      "metrics",
 			basename: "converted_modules.txt",