Toolchainize //scala/scalafmt:scalafmt_toolchain (bazelbuild#1678)

* 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 bazelbuild#1482.

* Make test_reproducibility.sh build test/coverage_*

Replaces the nonexistent `//test/coverage/...` target with packages that
actually exist, rendering the test more meaningful.

A spurious failure caused me to run the following to inspect what was
happening:

```txt
RULES_SCALA_TEST_ONLY=test_build_is_identical ./test_reproducibility.sh
```

This caused me to see that the following command was failing because
`//test/coverage/...` didn't exist:

```txt
bazel build --collect_code_coverage -- //test/coverage/...
```

* Export `SCALAFMT_TOOLCHAIN_TYPE` constant

Reduces string duplication in `//scala/scalafmt/toolchain/*.bzl` files.

* Remove scalafmt_toolchain dep_providers default

It's likely that no one will ever rely on the default when defining
their own `scalafmt_toolchain`.

While investigating bazelbuild#1675, I realized the `dep_providers` default was
set to a nonexistent target. This didn't break our tests because our
Scalafmt toolchains are created by `setup_scala_toolchain`, which sets
`dep_providers` explicitly.

I thought about aliasing the provider generated for the toolchain for
`SCALA_VERSION` in `@io_bazel_rules_scala_toolchains//scalafmt`, or
generating a new one. I ultimately decided to remove the default,
because the `deps_providers` is literally the only attribute. Anyone
defining their own `scalafmt_toolchain` will certainly define their own
`deps_providers` target(s).

* Update tests for Bazel 6 + Bzlmod

Copied the regular expression used to optionally match canonical repo
name prefixes in `buildozer` commands from bazelbuild#1622. These never failed
when building with Bzlmod and Bazel 7.4.1, but did under Bazel 6.5.0.

* Fix `//third_party` tests with `$(rootpath)`

Fixes `{strict_deps,unused_dependency_checker}_test` from
`//third_party/dependency_analyzer/src/test` under Bazel 8 by updating
`$(location)` to `$(rootpath)`. Part of bazelbuild#1652.

`//third_party/dependency_analyzer/src/test:strict_deps_test` and
`//third_party/dependency_analyzer/src/test:unused_dependency_checker_test`
both failed with errors of the form:

```txt
StrictDepsTest:
- error on indirect dependency target *** FAILED *** (379 milliseconds)
  nice errors on sequence of strings.this.infos.exists(nice errors on
  sequence of strings.this.checkErrorContainsMessage(target)) was false
  expected an error on //commons:Target to appear in errors (with
  buildozer command)!
  Errors: List(object apache is not a member of package org)
  (StrictDepsTest.scala:85)
```

This happened both under `WORKSPACE` and Bzlmod. Copying the test script
with the following (with `$ID` being one of `7`, `8`, `7-updated`, or
`8-updated`) helped reveal the differences:

```txt
cp bazel-bin/third_party/dependency_analyzer/src/test/strict_deps_test \
  strict_deps_test-$ID.sh
```

Under Bazel 7, we find the following lines whether using `$(location)`
or `$(rootpath)` on the `org.apache.commons` artifact (the other
artifacts already use `$(rootpath)`:

```txt
 -Dscala.library.location=external/io_bazel_rules_scala_scala_library_2_12_20/scala-library-2.12.20.jar
 -Dscala.reflect.location=external/io_bazel_rules_scala_scala_reflect_2_12_20/scala-reflect-2.12.20.jar
 -Dguava.jar.location=external/com_google_guava_guava_21_0_with_file/guava-21.0.jar
 -Dapache.commons.jar.location=external/org_apache_commons_commons_lang_3_5_without_file/commons-lang3-3.5.jar
```

Under Bazel 8, notice that the `external/` prefix has become `../` for
the other paths already using `$(rootpath)`, but remains `external/` for
the `$(location)` artifact. This breaks the Bazel 8 build:

```txt
-Dscala.library.location=../io_bazel_rules_scala_scala_library_2_12_20/scala-library-2.12.20.jar
-Dscala.reflect.location=../io_bazel_rules_scala_scala_reflect_2_12_20/scala-reflect-2.12.20.jar
-Dguava.jar.location=../com_google_guava_guava_21_0_with_file/guava-21.0.jar
-Dapache.commons.jar.location=external/org_apache_commons_commons_lang_3_5_without_file/commons-lang3-3.5.jar
```

Under Bazel 8, using `$(rootpath)` for the `org.apache.commons` artifact
converts its `external/`, fixing the Bazel 8 build:

```txt
-Dscala.library.location=../io_bazel_rules_scala_scala_library_2_12_20/scala-library-2.12.20.jar
-Dscala.reflect.location=../io_bazel_rules_scala_scala_reflect_2_12_20/scala-reflect-2.12.20.jar
-Dguava.jar.location=../com_google_guava_guava_21_0_with_file/guava-21.0.jar
-Dapache.commons.jar.location=../org_apache_commons_commons_lang_3_5_without_file/commons-lang3-3.5.jar
```

WORKSPACE

@@ -50,6 +50,7 @@ load("//scala:toolchains.bzl", "scala_toolchains")
 
 scala_toolchains(
     fetch_sources = True,
+    scalafmt = True,
     testing = True,
 )
 
@@ -71,12 +72,6 @@ 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()
-
 # needed for the cross repo proto test
 local_repository(
     name = "proto_cross_repo_boundary",

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

@@ -20,7 +20,7 @@ ext_scalafmt = {
         ),
         "_fmt": attr.label(
             cfg = "exec",
-            default = "//scala/scalafmt",
+            default = Label("//scala/scalafmt"),
             executable = True,
         ),
         "_java_host_runtime": attr.label(
@@ -30,19 +30,19 @@ ext_scalafmt = {
         ),
         "_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

@@ -4,6 +4,10 @@ load(
     "version_suffix",
     _default_maven_server_urls = "default_maven_server_urls",
 )
+load(
+    "//scala_proto/default:repositories.bzl",
+    "SCALAPB_COMPILE_ARTIFACT_IDS",
+)
 load("//third_party/repositories:repositories.bzl", "repositories")
 load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSIONS")
 
@@ -32,22 +36,16 @@ def scalafmt_default_config(path = ".scalafmt.conf", **kwargs):
 _SCALAFMT_DEPS = [
     "com_geirsson_metaconfig_core",
     "com_geirsson_metaconfig_typesafe_config",
-    "com_google_protobuf_protobuf_java",
     "com_lihaoyi_fansi",
-    "com_lihaoyi_fastparse",
-    "com_lihaoyi_sourcecode",
     "com_typesafe_config",
-    "org_scala_lang_modules_scala_collection_compat",
     "org_scala_lang_scalap",
     "org_scalameta_common",
     "org_scalameta_parsers",
     "org_scalameta_scalafmt_core",
     "org_scalameta_scalameta",
     "org_scalameta_trees",
     "org_typelevel_paiges_core",
-    "scala_proto_rules_scalapb_lenses",
-    "scala_proto_rules_scalapb_runtime",
-]
+] + SCALAPB_COMPILE_ARTIFACT_IDS
 
 _SCALAFMT_DEPS_2_11 = [
     "com_lihaoyi_pprint",
@@ -79,8 +77,7 @@ 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 +86,6 @@ 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/scalafmt/toolchain/setup_scalafmt_toolchain.bzl

@@ -1,4 +1,8 @@
-load("//scala/scalafmt/toolchain:toolchain.bzl", "scalafmt_toolchain")
+load(
+    "//scala/scalafmt/toolchain:toolchain.bzl",
+    "SCALAFMT_TOOLCHAIN_TYPE",
+    "scalafmt_toolchain",
+)
 load("//scala/scalafmt:scalafmt_repositories.bzl", "scalafmt_artifact_ids")
 load("//scala:providers.bzl", "declare_deps_provider")
 load("//scala:scala_cross_version.bzl", "version_suffix")
@@ -28,9 +32,7 @@ def setup_scalafmt_toolchain(
             version_suffix(scala_version),
         ],
         toolchain = ":%s_impl" % name,
-        toolchain_type = Label(
-            "//scala/scalafmt/toolchain:scalafmt_toolchain_type",
-        ),
+        toolchain_type = SCALAFMT_TOOLCHAIN_TYPE,
         visibility = visibility,
     )
 

scala/scalafmt/toolchain/toolchain.bzl

@@ -1,6 +1,10 @@
 load("@io_bazel_rules_scala//scala:providers.bzl", _DepsInfo = "DepsInfo")
 load("//scala/private/toolchain_deps:toolchain_deps.bzl", "expose_toolchain_deps")
 
+SCALAFMT_TOOLCHAIN_TYPE = Label(
+    "//scala/scalafmt/toolchain:scalafmt_toolchain_type",
+)
+
 def _scalafmt_toolchain_impl(ctx):
     toolchain = platform_common.ToolchainInfo(
         dep_providers = ctx.attr.dep_providers,
@@ -10,20 +14,12 @@ def _scalafmt_toolchain_impl(ctx):
 scalafmt_toolchain = rule(
     _scalafmt_toolchain_impl,
     attrs = {
-        "dep_providers": attr.label_list(
-            default = [
-                "@io_bazel_rules_scala//scala/scalafmt:scalafmt_classpath_provider",
-            ],
-            providers = [_DepsInfo],
-        ),
+        "dep_providers": attr.label_list(providers = [_DepsInfo]),
     },
 )
 
 def _export_scalafmt_deps_impl(ctx):
-    return expose_toolchain_deps(
-        ctx,
-        "@io_bazel_rules_scala//scala/scalafmt/toolchain:scalafmt_toolchain_type",
-    )
+    return expose_toolchain_deps(ctx, SCALAFMT_TOOLCHAIN_TYPE)
 
 export_scalafmt_deps = rule(
     _export_scalafmt_deps_impl,
@@ -32,6 +28,6 @@ export_scalafmt_deps = rule(
             mandatory = True,
         ),
     },
-    toolchains = ["@io_bazel_rules_scala//scala/scalafmt/toolchain:scalafmt_toolchain_type"],
+    toolchains = [SCALAFMT_TOOLCHAIN_TYPE],
     incompatible_use_toolchain_transition = True,
 )

scala/toolchains.bzl

@@ -2,8 +2,13 @@
 
 load("//junit:junit.bzl", "junit_artifact_ids")
 load("//scala/private:macros/scala_repositories.bzl", "scala_repositories")
-load("//scala: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("//scala:toolchains_repo.bzl", "scala_toolchains_repo")
 load("//scalatest:scalatest.bzl", "scalatest_artifact_ids")
 load("//specs2:specs2.bzl", "specs2_artifact_ids")
 load("//specs2:specs2_junit.bzl", "specs2_junit_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():

scala/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()
+"""

test/shell/test_scala_library.sh

@@ -59,14 +59,14 @@ test_scala_library_expect_failure_on_missing_direct_internal_deps() {
 }
 
 test_scala_library_expect_failure_on_missing_direct_external_deps_jar() {
-  dependenecy_target='@com_google_guava_guava_21_0//:com_google_guava_guava_21_0'
+  dependenecy_target='@[a-z_.~+-]*com_google_guava_guava_21_0//:com_google_guava_guava_21_0'
   test_target='test_expect_failure/missing_direct_deps/external_deps:transitive_external_dependency_user'
 
   test_scala_library_expect_failure_on_missing_direct_deps $dependenecy_target $test_target
 }
 
 test_scala_library_expect_failure_on_missing_direct_external_deps_file_group() {
-  dependenecy_target='@com_google_guava_guava_21_0_with_file//:com_google_guava_guava_21_0_with_file'
+  dependenecy_target='@[a-z_.~+-]*com_google_guava_guava_21_0_with_file//:com_google_guava_guava_21_0_with_file'
   test_target='test_expect_failure/missing_direct_deps/external_deps:transitive_external_dependency_user_file_group'
 
   test_scala_library_expect_failure_on_missing_direct_deps $dependenecy_target $test_target

test/shell/test_strict_dependency.sh

@@ -60,7 +60,7 @@ test_strict_deps_filter_excluded_target() {
 
 test_strict_deps_filter_included_target() {
   local test_target="//test_expect_failure/missing_direct_deps/filtering:b"
-  local expected_message="buildozer 'add deps @com_google_guava_guava_21_0//:com_google_guava_guava_21_0' ${test_target}"
+  local expected_message="buildozer 'add deps @[a-z_.~+-]*com_google_guava_guava_21_0//:com_google_guava_guava_21_0' ${test_target}"
 
   test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message \
     "${expected_message}" ${test_target} \

test/shell/test_unused_dependency.sh

@@ -79,7 +79,7 @@ test_unused_deps_filter_excluded_target() {
 
 test_unused_deps_filter_included_target() {
   local test_target="//test_expect_failure/unused_dependency_checker/filtering:b"
-  local expected_message="buildozer 'remove deps @com_google_guava_guava_21_0//:com_google_guava_guava_21_0' ${test_target}"
+  local expected_message="buildozer 'remove deps @[a-z_.~+-]*com_google_guava_guava_21_0//:com_google_guava_guava_21_0' ${test_target}"
 
   test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message \
     "${expected_message}" ${test_target} \

test_cross_build/WORKSPACE

@@ -66,11 +66,8 @@ 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()

test_reproducibility.sh

@@ -20,11 +20,18 @@ non_deploy_jar_md5_sum() {
     find bazel-bin/test -name "*.jar" ! -name "*_deploy.jar" ! -path 'bazel-bin/test/jmh/*' | xargs -n 1 -P 5 $(md5_util) | sort
 }
 
+
 test_build_is_identical() {
+    local test_coverage_packages=()
+
+    for package_dir in test/coverage_*; do
+        test_coverage_packages+=("//${package_dir}/...")
+    done
+
     bazel clean #ensure we are starting from square one
     bazel build test/...
     # Also build instrumented jars.
-    bazel build --collect_code_coverage -- //test/coverage/...
+    bazel build --collect_code_coverage -- "${test_coverage_packages[@]}"
     non_deploy_jar_md5_sum > hash1
     bazel clean
     sleep 10 # to make sure that if timestamps slip in we get different ones
@@ -37,7 +44,8 @@ test_build_is_identical() {
     fi
 
     bazel build --disk_cache $random_dir test/...
-    bazel build --disk_cache $random_dir --collect_code_coverage -- //test/coverage/...
+    bazel build --disk_cache $random_dir --collect_code_coverage -- \
+        "${test_coverage_packages[@]}"
     non_deploy_jar_md5_sum > hash2
     diff hash1 hash2
 }

third_party/dependency_analyzer/src/test/analyzer_test.bzl

@@ -57,7 +57,7 @@ def tests():
         ],
         jvm_flags = common_jvm_flags + [
             "-Dguava.jar.location=$(rootpath @com_google_guava_guava_21_0_with_file//jar)",
-            "-Dapache.commons.jar.location=$(location @org_apache_commons_commons_lang_3_5_without_file//:linkable_org_apache_commons_commons_lang_3_5_without_file)",
+            "-Dapache.commons.jar.location=$(rootpath @org_apache_commons_commons_lang_3_5_without_file//:linkable_org_apache_commons_commons_lang_3_5_without_file)",
         ],
         unused_dependency_checker_mode = "off",
         deps = scala_std_dependencies + [
@@ -76,7 +76,7 @@ def tests():
             "io/bazel/rulesscala/dependencyanalyzer/UnusedDependencyCheckerTest.scala",
         ],
         jvm_flags = common_jvm_flags + [
-            "-Dapache.commons.jar.location=$(location @org_apache_commons_commons_lang_3_5_without_file//:linkable_org_apache_commons_commons_lang_3_5_without_file)",
+            "-Dapache.commons.jar.location=$(rootpath @org_apache_commons_commons_lang_3_5_without_file//:linkable_org_apache_commons_commons_lang_3_5_without_file)",
         ],
         unused_dependency_checker_mode = "off",
         deps = scala_std_dependencies + [