Toolchainize //scala/scalafmt:scalafmt_toolchain

This is a pretty straightforward and easy update on top of the previous
`setup_toolchains` and `scala_toolchains_repo` changes. Part of bazel-contrib#1482.

Author: mbland

WORKSPACE

@@ -43,6 +43,7 @@ load("//scala:toolchains.bzl", "scala_toolchains")
 
 scala_toolchains(
     fetch_sources = True,
+    scalafmt = True,
     testing = True,
 )
 
@@ -81,12 +82,6 @@ load("//scala_proto:scala_proto.bzl", "scala_proto_repositories")
 
 scala_proto_repositories()
 
-load("//scala/scalafmt:scalafmt_repositories.bzl", "scalafmt_default_config", "scalafmt_repositories")
-
-scalafmt_default_config()
-
-scalafmt_repositories()
-
 MAVEN_SERVER_URLS = default_maven_server_urls()
 
 # needed for the cross repo proto test

scala/private/macros/toolchains_repo.bzl

@@ -50,6 +50,9 @@ def _scala_toolchains_repo_impl(repository_ctx):
         format_args.update(testing_build_args)
         toolchains["testing"] = _TESTING_TOOLCHAIN_BUILD
 
+    if repo_attr.scalafmt:
+        toolchains["scalafmt"] = _SCALAFMT_TOOLCHAIN_BUILD
+
     if len(toolchains) == 0:
         fail("no toolchains specified")
 
@@ -69,6 +72,7 @@ _scala_toolchains_repo = repository_rule(
         "junit": attr.bool(),
         "specs2": attr.bool(),
         "testing": attr.bool(),
+        "scalafmt": attr.bool(),
     },
 )
 
@@ -143,3 +147,12 @@ load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSIONS")
     for scala_version in SCALA_VERSIONS
 ]
 """
+
+_SCALAFMT_TOOLCHAIN_BUILD = """
+load(
+    "@@{rules_scala_repo}//scala/scalafmt/toolchain:setup_scalafmt_toolchain.bzl",
+    "setup_scalafmt_toolchains",
+)
+
+setup_scalafmt_toolchains()
+"""

scala/scalafmt/BUILD

@@ -1,4 +1,3 @@
-load("//scala/scalafmt/toolchain:setup_scalafmt_toolchain.bzl", "setup_scalafmt_toolchains")
 load("//scala/scalafmt/toolchain:toolchain.bzl", "export_scalafmt_deps")
 load("//scala/scalafmt:phase_scalafmt_ext.bzl", "scalafmt_singleton")
 load("//scala:scala.bzl", "scala_binary")
@@ -37,12 +36,13 @@ scalafmt_singleton(
     visibility = ["//visibility:public"],
 )
 
-setup_scalafmt_toolchains()
-
 # Alias for backward compatibility:
 alias(
     name = "scalafmt_toolchain",
-    actual = "scalafmt_toolchain" + version_suffix(SCALA_VERSION),
+    actual = (
+        "@io_bazel_rules_scala_toolchains//scalafmt:scalafmt_toolchain" +
+        version_suffix(SCALA_VERSION)
+    ),
 )
 
 export_scalafmt_deps(

scala/scalafmt/phase_scalafmt_ext.bzl

@@ -20,27 +20,27 @@ ext_scalafmt = {
         ),
         "_fmt": attr.label(
             cfg = "exec",
-            default = "//scala/scalafmt",
+            default = Label("//scala/scalafmt"),
             executable = True,
         ),
         "_java_host_runtime": attr.label(
             default = Label("@bazel_tools//tools/jdk:current_host_java_runtime"),
         ),
         "_runner": attr.label(
             allow_single_file = True,
-            default = "//scala/scalafmt:runner",
+            default = Label("//scala/scalafmt:runner"),
         ),
         "_testrunner": attr.label(
             allow_single_file = True,
-            default = "//scala/scalafmt:testrunner",
+            default = Label("//scala/scalafmt:testrunner"),
         ),
     },
     "outputs": {
         "scalafmt_runner": "%{name}.format",
         "scalafmt_testrunner": "%{name}.format-test",
     },
     "phase_providers": [
-        "//scala/scalafmt:phase_scalafmt",
+        Label("//scala/scalafmt:phase_scalafmt"),
     ],
 }
 

scala/scalafmt/scalafmt_repositories.bzl

@@ -79,8 +79,7 @@ def scalafmt_artifact_ids(scala_version):
 
 def scalafmt_repositories(
         maven_servers = _default_maven_server_urls(),
-        overriden_artifacts = {},
-        bzlmod_enabled = False):
+        overriden_artifacts = {}):
     for scala_version in SCALA_VERSIONS:
         repositories(
             scala_version = scala_version,
@@ -89,11 +88,6 @@ def scalafmt_repositories(
             overriden_artifacts = overriden_artifacts,
         )
 
-    if not bzlmod_enabled:
-        _register_scalafmt_toolchains()
-
-def _register_scalafmt_toolchains():
-    for scala_version in SCALA_VERSIONS:
         native.register_toolchains(str(Label(
             "//scala/scalafmt:scalafmt_toolchain" +
             version_suffix(scala_version),

scala/toolchains.bzl

@@ -3,6 +3,11 @@
 load("//junit:junit.bzl", "junit_artifact_ids")
 load("//scala/private:macros/scala_repositories.bzl", "scala_repositories")
 load("//scala/private:macros/toolchains_repo.bzl", "scala_toolchains_repo")
+load(
+    "//scala/scalafmt:scalafmt_repositories.bzl",
+    "scalafmt_artifact_ids",
+    "scalafmt_default_config",
+)
 load("//scala:scala_cross_version.bzl", "default_maven_server_urls")
 load("//scalatest:scalatest.bzl", "scalatest_artifact_ids")
 load("//specs2:specs2.bzl", "specs2_artifact_ids")
@@ -21,7 +26,9 @@ def scala_toolchains(
         scalatest = False,
         junit = False,
         specs2 = False,
-        testing = False):
+        testing = False,
+        scalafmt = False,
+        scalafmt_default_config_path = ".scalafmt.conf"):
     """Instantiates @io_bazel_rules_scala_toolchains and all its dependencies.
 
     Provides a unified interface to configuring rules_scala both directly in a
@@ -66,6 +73,9 @@ def scala_toolchains(
         specs2: whether to instantiate the Specs2 JUnit toolchain
         testing: whether to instantiate the Scalatest, JUnit, and Specs2 JUnit
             toolchains combined
+        scalafmt: whether to instantiate the Scalafmt toolchain
+        scalafmt_default_config_path: the relative path to the default Scalafmt
+            config file within the repository
     """
     scala_repositories(
         maven_servers = maven_servers,
@@ -78,6 +88,9 @@ def scala_toolchains(
         scala_compiler_srcjars = scala_compiler_srcjars,
     )
 
+    if scalafmt:
+        scalafmt_default_config(scalafmt_default_config_path)
+
     if testing:
         scalatest = True
         junit = True
@@ -106,6 +119,12 @@ def scala_toolchains(
     for scala_version in SCALA_VERSIONS:
         version_specific_artifact_ids = {}
 
+        if scalafmt:
+            version_specific_artifact_ids.update({
+                id: fetch_sources
+                for id in scalafmt_artifact_ids(scala_version)
+            })
+
         all_artifacts = (
             artifact_ids_to_fetch_sources | version_specific_artifact_ids
         )
@@ -125,6 +144,7 @@ def scala_toolchains(
         junit = junit,
         specs2 = specs2,
         testing = testing,
+        scalafmt = scalafmt,
     )
 
 def scala_register_toolchains():

test_cross_build/WORKSPACE

@@ -75,11 +75,8 @@ scala_config(
 load("@io_bazel_rules_scala//scala:toolchains.bzl", "scala_toolchains")
 
 scala_toolchains(
+    scalafmt = True,
     scalatest = True,
 )
 
 register_toolchains("@io_bazel_rules_scala_toolchains//...:all")
-
-load("@io_bazel_rules_scala//scala/scalafmt:scalafmt_repositories.bzl", "scalafmt_repositories")
-
-scalafmt_repositories()