Fix scala_proto_library default outputs (bazel-contrib#1701)

* Fix scala_proto_library default outputs

scala_proto_library returns too many outputs via DefaultInfo files

It returns all  transitive jar used for compilation while it should return
pair of srcjar and compile jar for each direct proto_library dependency

* make test pass

* Add test with multiple deps

Author: simuons

scala_proto/private/scala_proto.bzl

@@ -22,14 +22,11 @@ def phase_merge_aspect_java_info(ctx, p):
 
 def phase_default_info(ctx, p):
     java_info = p.merge_aspects.java_info
+    output_jars = [jar.class_jar for jar in java_info.outputs.jars]
+    source_jars = [jar.source_jar for jar in java_info.outputs.jars if jar.source_jar]
     return struct(
         external_providers = {
-            "DefaultInfo": DefaultInfo(
-                files = depset(
-                    java_info.source_jars,
-                    transitive = [java_info.full_compile_jars],
-                ),
-            ),
+            "DefaultInfo": DefaultInfo(files = depset(output_jars + source_jars)),
         },
     )
 

test/proto/BUILD

@@ -12,6 +12,7 @@ load(
     "//scala_proto:scala_proto_toolchain.bzl",
     "scala_proto_toolchain",
 )
+load(":default_outputs_test.bzl", "default_outputs_test")
 
 scala_proto_toolchain(
     name = "test_scala_proto_toolchain_configuration",
@@ -226,3 +227,36 @@ scala_test(
     unused_dependency_checker_mode = "off",
     deps = [":pack_protos_lib"],
 )
+
+scala_proto_library(
+    name = "standalone_scala_proto",
+    deps = [":standalone_proto"],
+)
+
+default_outputs_test(
+    name = "standalone_scala_proto_outs_test",
+    expected_outs = [
+        "standalone_proto_scalapb-src.jar",
+        "standalone_proto_scalapb.jar",
+    ],
+    target_under_test = ":standalone_scala_proto",
+)
+
+scala_proto_library(
+    name = "multiple_deps_scala_proto",
+    deps = [
+        ":test2",
+        ":test3",
+    ],
+)
+
+default_outputs_test(
+    name = "multiple_deps_scala_proto_outs_test",
+    expected_outs = [
+        "test2_scalapb-src.jar",
+        "test2_scalapb.jar",
+        "test3_scalapb-src.jar",
+        "test3_scalapb.jar",
+    ],
+    target_under_test = ":multiple_deps_scala_proto",
+)

test/proto/default_outputs_test.bzl

@@ -0,0 +1,18 @@
+load("@bazel_skylib//lib:unittest.bzl", "analysistest", "asserts")
+
+def _default_outputs_test(ctx):
+    env = analysistest.begin(ctx)
+
+    target_under_test = analysistest.target_under_test(env)
+    actual_outs = [f.basename for f in target_under_test[DefaultInfo].files.to_list()]
+
+    asserts.equals(env, sorted(ctx.attr.expected_outs), sorted(actual_outs))
+
+    return analysistest.end(env)
+
+default_outputs_test = analysistest.make(
+    _default_outputs_test,
+    attrs = {
+        "expected_outs": attr.string_list(),
+    },
+)