diff --git a/rules/scala_proto/private/core.bzl b/rules/scala_proto/private/core.bzl
index 44d7277e2..832f756e6 100644
--- a/rules/scala_proto/private/core.bzl
+++ b/rules/scala_proto/private/core.bzl
@@ -16,6 +16,7 @@ def scala_proto_library_implementation(ctx):
 
     protos = [dep.proto for dep in proto_deps]
 
+    direct_sources = depset(direct = [source for proto in protos for source in proto.direct_sources])
     transitive_sources = depset(transitive = [proto.transitive_sources for proto in protos])
     transitive_proto_path = depset(transitive = [proto.transitive_proto_path for proto in protos])
 
@@ -32,7 +33,7 @@ def scala_proto_library_implementation(ctx):
 
     args = ctx.actions.args()
     args.add("--output_dir", gendir.path)
-    args.add_all("--", transitive_sources)
+    args.add_all("--", direct_sources)
     args.set_param_file_format("multiline")
     args.use_param_file("@%s", use_always = True)
 
@@ -43,7 +44,7 @@ def scala_proto_library_implementation(ctx):
 
     ctx.actions.run(
         mnemonic = "ScalaProtoCompile",
-        inputs = depset(direct = [], transitive = [transitive_sources]),
+        inputs = depset(transitive = [transitive_sources]),
         outputs = [gendir],
         executable = compiler.compiler.files_to_run.executable,
         tools = compiler_inputs,
diff --git a/tests/proto/BUILD b/tests/proto/BUILD
index 8f10081bd..7becf8628 100644
--- a/tests/proto/BUILD
+++ b/tests/proto/BUILD
@@ -27,3 +27,30 @@ scala_library(
         "@annex_test//:com_thesamet_scalapb_scalapb_runtime_2_12",
     ],
 )
+
+proto_library(
+    name = "one_proto",
+    srcs = ["one.proto"],
+    deps = [
+        ":zero_proto",
+    ],
+    visibility = ["//visibility:public"],
+)
+
+scala_proto_library(
+    name = "one_scala_proto",
+    deps = [
+        ":one_proto",
+    ],
+)
+
+scala_library(
+    name = "one_scala",
+    srcs = [":one_scala_proto"],
+    deps = [
+        ":zero_scala",
+        "@annex_test//:com_google_protobuf_protobuf_java",
+        "@annex_test//:com_thesamet_scalapb_lenses_2_12",
+        "@annex_test//:com_thesamet_scalapb_scalapb_runtime_2_12",
+    ],
+)
diff --git a/tests/proto/expected_one b/tests/proto/expected_one
new file mode 100644
index 000000000..dfd1a417d
--- /dev/null
+++ b/tests/proto/expected_one
@@ -0,0 +1,10 @@
+-rw----     2.0 fat        0 bx  0% stor 20100101.000000 META-INF/
+-rw----     2.0 fat       48 b-  0% stor 20100101.000000 META-INF/MANIFEST.MF
+-rw----     1.0 fat        0 b-  0% stor 20100101.000000 anx/
+-rw----     1.0 fat        0 b-  0% stor 20100101.000000 anx/proto/
+-rw----     1.0 fat        0 b-  0% stor 20100101.000000 anx/proto/one/
+-rw----     2.0 fat    14827 b-  0% stor 20100101.000002 anx/proto/one/One$.class
+-rw----     2.0 fat     3097 b-  0% stor 20100101.000002 anx/proto/one/One$OneLens.class
+-rw----     2.0 fat    18959 b-  0% stor 20100101.000002 anx/proto/one/One.class
+-rw----     2.0 fat     6376 b-  0% stor 20100101.000002 anx/proto/one/OneProto$.class
+-rw----     2.0 fat     1937 b-  0% stor 20100101.000002 anx/proto/one/OneProto.class
diff --git a/tests/proto/expected b/tests/proto/expected_zero
similarity index 100%
rename from tests/proto/expected
rename to tests/proto/expected_zero
diff --git a/tests/proto/one.proto b/tests/proto/one.proto
new file mode 100644
index 000000000..5a405b476
--- /dev/null
+++ b/tests/proto/one.proto
@@ -0,0 +1,9 @@
+syntax = "proto2";
+
+option java_package = "anx.proto";
+
+import "proto/zero.proto";
+
+message One {
+  optional Zero zero = 1;
+}
diff --git a/tests/proto/test b/tests/proto/test
index 8effff763..437638dd2 100755
--- a/tests/proto/test
+++ b/tests/proto/test
@@ -4,6 +4,11 @@
 [[ "$(bazel version | head -n1 | cut -d: -f2 | tr -d ' ')" =~ 0.15.*|0.16.* ]] || bazel build :zero_scala_proto
 
 bazel build :zero_scala
-diff expected <(
+diff expected_zero <(
     zipinfo -m -T --h-t "$(bazel info bazel-bin)/proto/zero_scala.jar"
 )
+
+bazel build :one_scala
+diff expected_one <(
+    zipinfo -m -T --h-t "$(bazel info bazel-bin)/proto/one_scala.jar"
+)