Rust protobuf 2->3: Update build system

tldr: remove protobuf2 from Android Rust and upgrade everything to pb3.

These commits update:
- The grpcio rust crate to use protobuf 3
- The build system to always use the new libprotobuf (pb3) instead of the _deprecated variant (for pb2); they also force-enable libprotobuf everywhere, ignoring the use_protobuf3 flag, removes the tests related to pb2
- The following modules, which required syntax changes:
-- packages/modules/Bluetooth
-- device/google/cuttlefish
-- vendor/auto

Bug: 308790516
Test: m rust
Ignore-AOSP-First: must be done in main to upgrade cuttlefish+vendor with the rest all at once
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:7d0783ce22b3d7d369786d4b16067c79c033185b)
Merged-In: I1d07c433aca41ccfe2e710821cf930c413dc12d6
Change-Id: I1d07c433aca41ccfe2e710821cf930c413dc12d6

rust/protobuf.go

@@ -59,6 +59,7 @@ type ProtobufProperties struct {
 
 	// Use protobuf version 3.x. This will be deleted once we migrate all current users
 	// of protobuf off of 2.x.
+	// ludovicb@: DEPRECATED, to be removed
 	Use_protobuf3 *bool
 
 	// List of exported include paths containing proto files for dependent rust_protobuf modules.
@@ -77,10 +78,6 @@ type protobufDecorator struct {
 	protoFlags     android.ProtoFlags
 }
 
-func (proto *protobufDecorator) useProtobuf3() bool {
-	return Bool(proto.Properties.Use_protobuf3)
-}
-
 func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps) android.Path {
 	var protoFlags android.ProtoFlags
 	var grpcProtoFlags android.ProtoFlags
@@ -90,12 +87,7 @@ func (proto *protobufDecorator) GenerateSource(ctx ModuleContext, deps PathDeps)
 	protoFiles := android.PathsForModuleSrc(ctx, proto.Properties.Protos)
 	grpcFiles := android.PathsForModuleSrc(ctx, proto.Properties.Grpc_protos)
 
-	// For now protobuf2 (the deprecated version) remains the default. This will change in the
-	// future as we update the various users.
-	protoPluginPath := ctx.Config().HostToolPath(ctx, "protoc-gen-rust-deprecated")
-	if proto.useProtobuf3() == true {
-		protoPluginPath = ctx.Config().HostToolPath(ctx, "protoc-gen-rust")
-	}
+	protoPluginPath := ctx.Config().HostToolPath(ctx, "protoc-gen-rust")
 
 	commonProtoFlags = append(commonProtoFlags, defaultProtobufFlags...)
 	commonProtoFlags = append(commonProtoFlags, proto.Properties.Proto_flags...)
@@ -219,13 +211,7 @@ func (proto *protobufDecorator) genModFileContents() string {
 		lines = append(
 			lines,
 			"pub mod empty {",
-			"    pub use protobuf::well_known_types::Empty;",
-			"}",
-			"pub mod wrappers {",
-			"    pub use protobuf::well_known_types::{",
-			"        DoubleValue, FloatValue, Int64Value, UInt64Value, Int32Value, UInt32Value,",
-			"        BoolValue, StringValue, BytesValue",
-			"    };",
+			"    pub use protobuf::well_known_types::empty::Empty;",
 			"}")
 	}
 
@@ -238,20 +224,10 @@ func (proto *protobufDecorator) SourceProviderProps() []interface{} {
 
 func (proto *protobufDecorator) SourceProviderDeps(ctx DepsContext, deps Deps) Deps {
 	deps = proto.BaseSourceProvider.SourceProviderDeps(ctx, deps)
-	useProtobuf3 := proto.useProtobuf3()
-	if useProtobuf3 == true {
-		deps.Rustlibs = append(deps.Rustlibs, "libprotobuf")
-	} else {
-		deps.Rustlibs = append(deps.Rustlibs, "libprotobuf_deprecated")
-	}
+	deps.Rustlibs = append(deps.Rustlibs, "libprotobuf")
 	deps.HeaderLibs = append(deps.SharedLibs, proto.Properties.Header_libs...)
 
 	if len(proto.Properties.Grpc_protos) > 0 {
-		if useProtobuf3 == true {
-			ctx.PropertyErrorf("protos", "rust_protobuf with grpc_protos defined must currently use "+
-				"`use_protobuf3: false,` in the Android.bp file. This is temporary until the "+
-				"grpcio crate is updated to use the current version of the protobuf crate.")
-		}
 		deps.Rustlibs = append(deps.Rustlibs, "libgrpcio", "libfutures")
 		deps.HeaderLibs = append(deps.HeaderLibs, "libprotobuf-cpp-full")
 	}

rust/protobuf_test.go

@@ -21,54 +21,6 @@ import (
 	"android/soong/android"
 )
 
-func TestRustProtobuf(t *testing.T) {
-	ctx := testRust(t, `
-		rust_protobuf {
-			name: "librust_proto",
-			protos: ["buf.proto", "proto.proto"],
-			crate_name: "rust_proto",
-			source_stem: "buf",
-			shared_libs: ["libfoo_shared"],
-			static_libs: ["libfoo_static"],
-		}
-		cc_library_shared {
-			name: "libfoo_shared",
-			export_include_dirs: ["shared_include"],
-		}
-		cc_library_static {
-			name: "libfoo_static",
-			export_include_dirs: ["static_include"],
-		}
-	`)
-	// Check that libprotobuf is added as a dependency.
-	librust_proto := ctx.ModuleForTests("librust_proto", "android_arm64_armv8-a_dylib").Module().(*Module)
-	if !android.InList("libprotobuf_deprecated", librust_proto.Properties.AndroidMkDylibs) {
-		t.Errorf("libprotobuf_deprecated dependency missing for rust_protobuf (dependency missing from AndroidMkDylibs)")
-	}
-
-	// Make sure the correct plugin is being used.
-	librust_proto_out := ctx.ModuleForTests("librust_proto", "android_arm64_armv8-a_source").Output("buf.rs")
-	cmd := librust_proto_out.RuleParams.Command
-	if w := "protoc-gen-rust-deprecated"; !strings.Contains(cmd, w) {
-		t.Errorf("expected %q in %q", w, cmd)
-	}
-
-	// Check exported include directories
-	if w := "-Ishared_include"; !strings.Contains(cmd, w) {
-		t.Errorf("expected %q in %q", w, cmd)
-	}
-	if w := "-Istatic_include"; !strings.Contains(cmd, w) {
-		t.Errorf("expected %q in %q", w, cmd)
-	}
-
-	// Check proto.rs, the second protobuf, is listed as an output
-	librust_proto_outputs := ctx.ModuleForTests("librust_proto", "android_arm64_armv8-a_source").AllOutputs()
-	if android.InList("proto.rs", librust_proto_outputs) {
-		t.Errorf("rust_protobuf is not producing multiple outputs; expected 'proto.rs' in list, got: %#v ",
-			librust_proto_outputs)
-	}
-}
-
 func TestRustProtobuf3(t *testing.T) {
 	ctx := testRust(t, `
 		rust_protobuf {

rust/testing.go

@@ -132,12 +132,6 @@ func GatherRequiredDepsForTest() string {
 			srcs: ["foo.rs"],
 			host_supported: true,
 		}
-		rust_library {
-			name: "libprotobuf_deprecated",
-			crate_name: "protobuf",
-			srcs: ["foo.rs"],
-			host_supported: true,
-		}
 		rust_library {
 			name: "libgrpcio",
 			crate_name: "grpcio",