Move scala_binary to its own file (#813)

* add a note about code organization in CONTRIBUTING.md

* wip move scala_binary out

* fully split out scala_binary properly

* _library_outputs is the same thing as common_outputs

* fix a bunch more scalac_provider references

* rename scala_provider function to get_scalac_provider per review

* back to the old variable names

CONTRIBUTING.md

@@ -17,6 +17,12 @@ Before you start working on a larger contribution, you should get in touch
 with us first. Use the issue tracker to explain your idea so we can help and
 possibly guide you.
 
+### Code organization
+
+Core Scala rules (including their implementations) and macros go in [./scala/private/rules/](./scala/private/rules/)
+and [./scala/private/macros/](./scala/private/macros/), respectively, and are re-exported for public use
+in [./scala/scala.bzl](./scala/scala.bzl).
+
 ### Code reviews and other contributions.
 **All submissions, including submissions by project members, require review.**
 Please follow the instructions in [the contributors documentation](http://bazel.io/contributing.html).

scala/private/common_attributes.bzl

@@ -0,0 +1,137 @@
+"""Shared attributes for rules"""
+
+load(
+    "@io_bazel_rules_scala//scala/private:coverage_replacements_provider.bzl",
+    _coverage_replacements_provider = "coverage_replacements_provider",
+)
+load(
+    "@io_bazel_rules_scala//scala:plusone.bzl",
+    _collect_plus_one_deps_aspect = "collect_plus_one_deps_aspect",
+)
+
+common_attrs_for_plugin_bootstrapping = {
+    "srcs": attr.label_list(allow_files = [
+        ".scala",
+        ".srcjar",
+        ".java",
+    ]),
+    "deps": attr.label_list(
+        aspects = [
+            _collect_plus_one_deps_aspect,
+            _coverage_replacements_provider.aspect,
+        ],
+        providers = [[JavaInfo]],
+    ),
+    "plugins": attr.label_list(allow_files = [".jar"]),
+    "runtime_deps": attr.label_list(providers = [[JavaInfo]]),
+    "data": attr.label_list(allow_files = True),
+    "resources": attr.label_list(allow_files = True),
+    "resource_strip_prefix": attr.string(),
+    "resource_jars": attr.label_list(allow_files = True),
+    "scalacopts": attr.string_list(),
+    "javacopts": attr.string_list(),
+    "jvm_flags": attr.string_list(),
+    "scalac_jvm_flags": attr.string_list(),
+    "javac_jvm_flags": attr.string_list(),
+    "expect_java_output": attr.bool(
+        default = True,
+        mandatory = False,
+    ),
+    "print_compile_time": attr.bool(
+        default = False,
+        mandatory = False,
+    ),
+}
+
+common_attrs = {}
+
+common_attrs.update(common_attrs_for_plugin_bootstrapping)
+
+common_attrs.update({
+    # using stricts scala deps is done by using command line flag called 'strict_java_deps'
+    # switching mode to "on" means that ANY API change in a target's transitive dependencies will trigger a recompilation of that target,
+    # on the other hand any internal change (i.e. on code that ijar omits) WON’T trigger recompilation by transitive dependencies
+    "_dependency_analyzer_plugin": attr.label(
+        default = Label(
+            "@io_bazel_rules_scala//third_party/dependency_analyzer/src/main:dependency_analyzer",
+        ),
+        allow_files = [".jar"],
+        mandatory = False,
+    ),
+    "unused_dependency_checker_mode": attr.string(
+        values = [
+            "warn",
+            "error",
+            "off",
+            "",
+        ],
+        mandatory = False,
+    ),
+    "_unused_dependency_checker_plugin": attr.label(
+        default = Label(
+            "@io_bazel_rules_scala//third_party/unused_dependency_checker/src/main:unused_dependency_checker",
+        ),
+        allow_files = [".jar"],
+        mandatory = False,
+    ),
+    "unused_dependency_checker_ignored_targets": attr.label_list(default = []),
+    "_code_coverage_instrumentation_worker": attr.label(
+        default = "@io_bazel_rules_scala//src/java/io/bazel/rulesscala/coverage/instrumenter",
+        allow_files = True,
+        executable = True,
+        cfg = "host",
+    ),
+})
+
+implicit_deps = {
+    "_singlejar": attr.label(
+        executable = True,
+        cfg = "host",
+        default = Label("@bazel_tools//tools/jdk:singlejar"),
+        allow_files = True,
+    ),
+    "_zipper": attr.label(
+        executable = True,
+        cfg = "host",
+        default = Label("@bazel_tools//tools/zip:zipper"),
+        allow_files = True,
+    ),
+    "_java_toolchain": attr.label(
+        default = Label("@bazel_tools//tools/jdk:current_java_toolchain"),
+    ),
+    "_host_javabase": attr.label(
+        default = Label("@bazel_tools//tools/jdk:current_java_runtime"),
+        cfg = "host",
+    ),
+    "_java_runtime": attr.label(
+        default = Label("@bazel_tools//tools/jdk:current_java_runtime"),
+    ),
+    "_scalac": attr.label(
+        default = Label(
+            "@io_bazel_rules_scala//src/java/io/bazel/rulesscala/scalac",
+        ),
+    ),
+    "_exe": attr.label(
+        executable = True,
+        cfg = "host",
+        default = Label("@io_bazel_rules_scala//src/java/io/bazel/rulesscala/exe:exe"),
+    ),
+}
+
+launcher_template = {
+    "_java_stub_template": attr.label(
+        default = Label("@io_bazel_rules_scala//java_stub_template/file"),
+    ),
+}
+
+# Single dep to allow IDEs to pickup all the implicit dependencies.
+resolve_deps = {
+    "_scala_toolchain": attr.label_list(
+        default = [
+            Label(
+                "//external:io_bazel_rules_scala/dependency/scala/scala_library",
+            ),
+        ],
+        allow_files = False,
+    ),
+}

scala/private/common_outputs.bzl

@@ -0,0 +1,8 @@
+"""Common outputs used in rule outputs"""
+
+common_outputs = {
+    "jar": "%{name}.jar",
+    "deploy_jar": "%{name}_deploy.jar",
+    "manifest": "%{name}_MANIFEST.MF",
+    "statsfile": "%{name}.statsfile",
+}