A couple fixes to the Rust Proto bzl to make proto libraries that use strip_import_prefix or import_prefix work with Rust Proto.

PiperOrigin-RevId: 689799840

rust/BUILD

@@ -212,6 +212,7 @@ rust_library(
 proto_lang_toolchain(
     name = "proto_rust_upb_toolchain",
     command_line = "--rust_out=$(OUT)",
+    output_files = "multiple",
     progress_message = "Generating Rust proto_library %{label}",
     runtime = ":protobuf_upb",
     visibility = ["//visibility:public"],
@@ -220,6 +221,7 @@ proto_lang_toolchain(
 proto_lang_toolchain(
     name = "proto_rust_cpp_toolchain",
     command_line = "--rust_out=$(OUT)",
+    output_files = "multiple",
     progress_message = "Generating Rust proto_library %{label}",
     runtime = ":protobuf_cpp",
     visibility = ["//visibility:public"],

rust/aspects.bzl

@@ -298,7 +298,7 @@ def _rust_proto_aspect_common(target, ctx, is_upb):
         unsupported_features = ctx.disabled_features,
     )
 
-    proto_srcs = getattr(ctx.rule.files, "srcs", [])
+    proto_srcs = target[ProtoInfo].direct_sources
     proto_deps = getattr(ctx.rule.attr, "deps", [])
     transitive_crate_mappings = []
     for dep in proto_deps: