Passing source-jar into JavaInfo

scala/private/rule_impls.bzl

@@ -401,7 +401,7 @@ def _compile_or_empty(
     if len(ctx.files.srcs) + len(srcjars.to_list()) == 0:
         _build_nosrc_jar(ctx)
 
-        scala_compilation_provider = _create_scala_compilation_provider(ctx, ctx.outputs.jar, deps_providers)
+        scala_compilation_provider = _create_scala_compilation_provider(ctx, ctx.outputs.jar, None, deps_providers)
 
         #  no need to build ijar when empty
         return struct(
@@ -476,7 +476,8 @@ def _compile_or_empty(
             #  so set ijar == jar
             ijar = ctx.outputs.jar
 
-        scala_compilation_provider = _create_scala_compilation_provider(ctx, ijar, deps_providers)
+        source_jar = _pack_source_jar(ctx)
+        scala_compilation_provider = _create_scala_compilation_provider(ctx, ijar, source_jar, deps_providers)
 
         # compile the java now
         java_jar = try_to_compile_java_jar(
@@ -513,7 +514,7 @@ def _compile_or_empty(
             merged_provider = merged_provider
         )
 
-def _create_scala_compilation_provider(ctx, ijar, deps_providers):
+def _create_scala_compilation_provider(ctx, ijar, source_jar, deps_providers):
     exports = []
     if hasattr(ctx.attr, "exports"):
         exports = [dep[JavaInfo] for dep in ctx.attr.exports]
@@ -523,6 +524,7 @@ def _create_scala_compilation_provider(ctx, ijar, deps_providers):
     return JavaInfo(
         output_jar = ctx.outputs.jar,
         compile_jar = ijar,
+        source_jar = source_jar,
         deps = deps_providers,
         exports = exports,
         runtime_deps = runtime_deps,
@@ -962,9 +964,7 @@ def _scala_binary_common(
             rjars,  #calling rules need this for the classpath in the launcher
     )
 
-def _pack_source_jars(ctx):
-    source_jars = []
-
+def _pack_source_jar(ctx):
     # collect .scala sources and pack a source jar for Scala
     scala_sources = [
         f
@@ -986,10 +986,13 @@ def _pack_source_jars(ctx):
         java_toolchain = find_java_toolchain(ctx, ctx.attr._java_toolchain),
         host_javabase = find_java_runtime_toolchain(ctx, ctx.attr._host_javabase),
     )
-    if scala_source_jar:
-        source_jars.append(scala_source_jar)
 
-    return source_jars
+    return scala_source_jar
+
+def _pack_source_jars(ctx):
+    source_jar = _pack_source_jar(ctx)
+    #_pack_source_jar may return None if java_common.pack_sources returned None (and it can)
+    return [source_jar] if source_jar else []
 
 def scala_binary_impl(ctx):
     scalac_provider = _scalac_provider(ctx)

scala/scala_import.bzl

@@ -25,11 +25,10 @@ def _scala_import_impl(ctx):
         jars2labels,
     )  #last to override the label of the export compile jars to the current target
 
-    current_target_providers = [_new_java_info(ctx, jar) for jar in current_target_compile_jars]
-
-    # Handle the case with no jars.
-    # TODO(#8867): Migrate away from the placeholder jar hack when #8867 is fixed.
-    if not current_target_providers:
+    if current_target_compile_jars:
+        current_target_providers = [_new_java_info(ctx, jar) for jar in current_target_compile_jars]
+    else:
+        # TODO(#8867): Migrate away from the placeholder jar hack when #8867 is fixed.
         current_target_providers = [_new_java_info(ctx, ctx.file._placeholder_jar)]
 
     return struct(

test_expect_failure/missing_direct_deps/internal_deps/BUILD

@@ -44,7 +44,6 @@ scala_library(
 
 custom_jvm(
     name = "direct_java_provider_dependency",
-    main = "//test/src/main/resources/scalarules/test:hellos-and-byes.jar", #just any jar would do
     deps = ["transitive_dependency"],
 )
 

test_expect_failure/missing_direct_deps/internal_deps/custom-jvm-rule.bzl

@@ -1,6 +1,7 @@
 #This rule is an example for a jvm rule that doesn't support Jars2Labels
 def _custom_jvm_impl(ctx):   
-    jar = ctx.file.main
+    # TODO(#8867): Migrate away from the placeholder jar hack when #8867 is fixed.
+    jar = ctx.file._placeholder_jar
     provider = JavaInfo(output_jar = jar,
              compile_jar = jar,
              deps = [target[JavaInfo] for target in ctx.attr.deps]
@@ -10,7 +11,10 @@ def _custom_jvm_impl(ctx):
 custom_jvm = rule(
     implementation = _custom_jvm_impl,
     attrs = {
-        "main": attr.label(allow_single_file = True), #just used so we'll be able to build the JavaInfo with a "main" jar
         "deps": attr.label_list(),
+        "_placeholder_jar": attr.label(
+            allow_single_file = True,
+            default = Label("@io_bazel_rules_scala//scala:libPlaceHolderClassToCreateEmptyJarForScalaImport.jar"),
+        ),
     },
 )

twitter_scrooge/twitter_scrooge.bzl

@@ -372,7 +372,8 @@ def _scrooge_scala_library_impl(ctx):
     )
     if ctx.attr.exports:
         exports = [exp[JavaInfo] for exp in ctx.attr.exports]
-        all_java = java_common.merge(_concat_lists(exports, [aspect_info.java_info]))
+        exports.append(aspect_info.java_info)
+        all_java = java_common.merge(exports)
     else:
         all_java = aspect_info.java_info