Introduce Scala config (bazel-contrib#1133)

* Add scala config repository to store global configuration options

* Fix example workspace

* Add docs

* Get bazel version directly

* Remove unused skylib load

Author: liucijus

README.md

@@ -54,8 +54,11 @@ http_archive(
     sha256 = "8c48283aeb70e7165af48191b0e39b7434b0368718709d1bced5c3781787d8e7",
 )
 
-load("@io_bazel_rules_scala//:version.bzl", "bazel_version")
-bazel_version(name = "bazel_version")
+# Stores Scala version and other configuration
+# 2.12 is a default version, other versions can be use by passing them explicitly:
+# scala_config(scala_version = "2.11.12")
+load("@io_bazel_rules_scala//:scala_config.bzl", "scala_config")
+scala_config()
 
 load("@io_bazel_rules_scala//scala:toolchains.bzl", "scala_register_toolchains")
 scala_register_toolchains()

WORKSPACE

@@ -26,15 +26,16 @@ load("@com_github_bazelbuild_buildtools//buildifier:deps.bzl", "buildifier_depen
 
 buildifier_dependencies()
 
-load("@io_bazel_rules_scala//:version.bzl", "bazel_version")
+load("@io_bazel_rules_scala//:scala_config.bzl", "scala_config")
 
-bazel_version(name = "bazel_version")
+scala_config()
 
+load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_MAJOR_VERSION")
 load("//scala:scala.bzl", "scala_repositories")
 
 scala_repositories(fetch_sources = True)
 
-load("//scala:scala_cross_version.bzl", "default_maven_server_urls")
+load("//scala:scala_cross_version.bzl", "default_maven_server_urls", "scala_mvn_artifact")
 load("//scala:scala_maven_import_external.bzl", "scala_maven_import_external")
 load("//twitter_scrooge:twitter_scrooge.bzl", "twitter_scrooge")
 
@@ -64,13 +65,6 @@ scalafmt_default_config()
 
 scalafmt_repositories()
 
-load(
-    "//scala:scala_cross_version.bzl",
-    "default_scala_major_version",
-    "default_scala_version",
-    "scala_mvn_artifact",
-)
-
 MAVEN_SERVER_URLS = default_maven_server_urls()
 
 # needed for the cross repo proto test
@@ -177,7 +171,7 @@ jvm_maven_import_external(
     name = "org_typelevel__cats_core",
     artifact = scala_mvn_artifact(
         "org.typelevel:cats-core:0.9.0",
-        default_scala_major_version(),
+        SCALA_MAJOR_VERSION,
     ),
     artifact_sha256 = "3ca705cba9dc0632e60477d80779006f8c636c0e2e229dda3410a0c314c1ea1d",
     server_urls = MAVEN_SERVER_URLS,
@@ -207,5 +201,4 @@ repositories(
         "org_spire_math_kind_projector",
     ],
     maven_servers = MAVEN_SERVER_URLS,
-    scala_version = default_scala_version(),
 )

examples/testing/scalatest_repositories/WORKSPACE

@@ -16,9 +16,9 @@ local_repository(
     path = "../../..",
 )
 
-load("@io_bazel_rules_scala//:version.bzl", "bazel_version")
+load("@io_bazel_rules_scala//:scala_config.bzl", "scala_config")
 
-bazel_version(name = "bazel_version")
+scala_config()
 
 load("@io_bazel_rules_scala//scala:scala.bzl", "scala_repositories")
 

jmh/jmh.bzl

@@ -2,12 +2,10 @@ load("//scala:scala.bzl", "scala_binary", "scala_library")
 load(
     "//scala:scala_cross_version.bzl",
     "default_maven_server_urls",
-    "default_scala_version",
 )
 load("//third_party/repositories:repositories.bzl", "repositories")
 
 def jmh_repositories(
-        scala_version = default_scala_version(),
         maven_servers = default_maven_server_urls(),
         overriden_artifacts = {}):
     repositories(
@@ -21,7 +19,6 @@ def jmh_repositories(
             "io_bazel_rules_scala_org_apache_commons_commons_math3",
         ],
         fetch_sources = False,
-        scala_version = scala_version,
         maven_servers = maven_servers,
         overriden_artifacts = {},
     )

scala/private/macros/scala_repositories.bzl

@@ -2,7 +2,6 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load(
     "@io_bazel_rules_scala//scala:scala_cross_version.bzl",
     _default_maven_server_urls = "default_maven_server_urls",
-    _default_scala_version = "default_scala_version",
 )
 load("//third_party/repositories:repositories.bzl", "repositories")
 
@@ -70,7 +69,6 @@ def rules_scala_setup():
         )
 
 def scala_repositories(
-        scala_version = _default_scala_version(),
         maven_servers = _default_maven_server_urls(),
         overriden_artifacts = {},
         fetch_sources = False):
@@ -89,7 +87,6 @@ def scala_repositories(
         maven_servers = _default_maven_server_urls(),
         fetch_sources = fetch_sources,
         overriden_artifacts = overriden_artifacts,
-        scala_version = scala_version,
     )
 
     native.bind(

scala/private/rule_impls.bzl

@@ -20,7 +20,7 @@ load(
     _collect_plugin_paths = "collect_plugin_paths",
 )
 load(":resources.bzl", _resource_paths = "paths")
-load("@bazel_version//:def.bzl", "BAZEL_VERSION")
+load("@io_bazel_rules_scala_config//:config.bzl", "BAZEL_VERSION")
 
 def expand_location(ctx, flags):
     if hasattr(ctx.attr, "data"):

scala/scala_cross_version.bzl

@@ -15,10 +15,6 @@
 of abstracting over Scala major version (2.11, 2.12, etc) for dependency
 resolution."""
 
-def default_scala_version():
-    """return the scala version for use in maven coordinates"""
-    return "2.12.11"
-
 def default_maven_server_urls():
     return [
         "https://repo.maven.apache.org/maven2",
@@ -36,12 +32,9 @@ def extract_major_version_underscore(scala_version):
     e.g. "2.11.11" -> "2_11" """
     return extract_major_version(scala_version).replace(".", "_")
 
-def default_scala_major_version():
-    return extract_major_version(default_scala_version())
-
 def scala_mvn_artifact(
         artifact,
-        major_scala_version = default_scala_major_version()):
+        major_scala_version):
     """Add scala version to maven artifact"""
     gav = artifact.split(":")
     groupid = gav[0]

scala/scalafmt/scalafmt_repositories.bzl

@@ -1,7 +1,6 @@
 load(
     "//scala:scala_cross_version.bzl",
     _default_maven_server_urls = "default_maven_server_urls",
-    _default_scala_version = "default_scala_version",
 )
 load("//third_party/repositories:repositories.bzl", "repositories")
 
@@ -15,7 +14,6 @@ def scalafmt_default_config(path = ".scalafmt.conf"):
     native.new_local_repository(name = "scalafmt_default", build_file_content = "\n".join(build), path = "")
 
 def scalafmt_repositories(
-        scala_version = _default_scala_version(),
         maven_servers = _default_maven_server_urls(),
         overriden_artifacts = {}):
     repositories(
@@ -45,6 +43,5 @@ def scalafmt_repositories(
         maven_servers = maven_servers,
         fetch_sources = True,
         overriden_artifacts = overriden_artifacts,
-        scala_version = scala_version,
     )
     native.register_toolchains("@io_bazel_rules_scala//scala/scalafmt:scalafmt_toolchain")

scala_config.bzl

@@ -0,0 +1,34 @@
+load("//scala:scala_cross_version.bzl", "extract_major_version")
+
+def _default_scala_version():
+    """return the scala version for use in maven coordinates"""
+    return "2.12.11"
+
+def _store_config(repository_ctx):
+    repository_ctx.file("BUILD", "exports_files(['def.bzl'])")
+
+    scala_version = repository_ctx.attr.scala_version
+    scala_major_version = extract_major_version(scala_version)
+
+    config_file_content = "\n".join([
+        "BAZEL_VERSION='" + native.bazel_version + "'",
+        "SCALA_VERSION='" + scala_version + "'",
+        "SCALA_MAJOR_VERSION='" + scala_major_version + "'",
+    ])
+
+    repository_ctx.file("config.bzl", config_file_content)
+
+_config_repository = repository_rule(
+    implementation = _store_config,
+    attrs = {
+        "scala_version": attr.string(
+            mandatory = True,
+        ),
+    },
+)
+
+def scala_config(scala_version = _default_scala_version()):
+    _config_repository(
+        name = "io_bazel_rules_scala_config",
+        scala_version = scala_version,
+    )

scala_proto/private/scala_proto_default_repositories.bzl

@@ -1,13 +1,10 @@
 load(
     "//scala:scala_cross_version.bzl",
     _default_maven_server_urls = "default_maven_server_urls",
-    _default_scala_version = "default_scala_version",
-    _scala_mvn_artifact = "scala_mvn_artifact",
 )
 load("//third_party/repositories:repositories.bzl", "repositories")
 
 def scala_proto_default_repositories(
-        scala_version = _default_scala_version(),
         maven_servers = _default_maven_server_urls(),
         overriden_artifacts = {}):
     repositories(
@@ -43,7 +40,6 @@ def scala_proto_default_repositories(
             "scala_proto_rules_opencensus_impl_core",
             "scala_proto_rules_opencensus_contrib_grpc_metrics",
         ],
-        scala_version = scala_version,
         maven_servers = maven_servers,
         fetch_sources = True,
         overriden_artifacts = overriden_artifacts,