Rename {io_bazel_,}rules_scala_config (bazel-contrib#1709)

Shortens `@io_bazel_rules_scala_config` to `@rules_scala_config` in
light of the `@io_bazel_rules_scala` removal in bazel-contrib#1696. Part of bazel-contrib#1482.

Adds a section to `README.md` indicating this as a breaking change, with
advice on working around any breakages that aren't immediately fixable.

Includes updates the "Builtin repositories no longer visible by default
under Bzlmod" section to improve clarity.

Per @simuons's advice in
bazel-contrib#1703 (comment).

Author: mbland

README.md

@@ -495,6 +495,80 @@ extension. However, you must register explicitly in your `MODULE.bazel` file any
 toolchains that you want to take precedence over the toolchains configured by
 `scala_deps`.
 
+### `@io_bazel_rules_scala_config` is now `@rules_scala_config`
+
+Since `@io_bazel_rules_scala` is no longer hardcoded in `rules_scala` internals,
+we've shortened `@io_bazel_rules_scala_config` to `@rules_scala_config`. This
+shouldn't affect most users, but it may break some builds using
+`@io_bazel_rules_scala_config` to define custom [cross-compilation targets](
+./docs/cross-compilation.md).
+
+If you can't fix uses of `@io_bazel_rules_scala_config` in your own project
+immediately, you can remap `@rules_scala_config` via [`use_repo()`]:
+
+[`use_repo()`]: https://bazel.build/rules/lib/globals/module#use_repo
+
+```py
+scala_config = use_extension(
+    "@rules_scala//scala/extensions:config.bzl",
+    "scala_config",
+)
+
+use_repo(scala_config, io_bazel_rules_scala_config = "rules_scala_config")
+```
+
+If any of your dependencies still require `@io_bazel_rules_scala_config`, use
+one of the following mechanisms to override it with `@rules_scala_config`:
+
+#### Bzlmod
+
+For [`bazel_dep()`][] dependencies, use [`override_repo()`][] to
+override `@io_bazel_rules_scala_config` with `@rules_scala_config`:
+
+```py
+bazel_dep(name = "foo", version = "1.0.0")
+
+foo_ext = use_extension("@foo//:ext.bzl", "foo_ext")
+override_repo(foo_ext, io_bazel_rules_scala_config = "rules_scala_config")
+```
+
+[`bazel_dep()`]: https://bazel.build/rules/lib/globals/module#bazel_dep
+[`override_repo()`]: https://bazel.build/rules/lib/globals/module#override_repo
+
+For [`archive_override()`][] and [`git_override()`][] dependencies, use the
+`repo_mapping` attribute passed through to the underlying [`http_archive()`][]
+and [`git_repository()`][] rules:
+
+```py
+archive_override(
+    ...
+    repo_mapping = {
+        "@io_bazel_rules_scala_config": "@rules_scala_config",
+    }
+    ...
+)
+```
+
+[`archive_override()`]: https://bazel.build/rules/lib/globals/module#archive_override
+[`git_override()`]: https://bazel.build/rules/lib/globals/module#git_override
+[`http_archive()`]: https://bazel.build/rules/lib/repo/http#http_archive-repo_mapping
+[`git_repository()`]: https://bazel.build/rules/lib/repo/git#git_repository-repo_mapping
+
+#### `WORKSPACE`
+
+Use the `repo_mapping` attribute of [`http_archive()`][] or
+[`git_repository()`][]:
+
+```py
+http_archive(
+    ...
+    repo_mapping = {
+        "@io_bazel_rules_scala_config": "@rules_scala_config",
+    }
+    ...
+)
+```
+
 ### Bzlmod configuration (coming soon!)
 
 The upcoming Bzlmod implementation will funnel through the `scala_toolchains()`
@@ -565,7 +639,7 @@ now, as there's not yet a corresponding [`toolchain_type()`](
 https://bazel.build/versions/6.1.0/reference/be/platform#toolchain_type) target
 in `@rules_java`.
 
-### Builtin repositories no longer visible without `use_repo()` under Bzlmod
+### Builtin repositories no longer visible by default under Bzlmod
 
 Under Bzlmod, repos are only visible to the module extension that creates them,
 unless the `MODULE.bazel` file brings them into scope with
@@ -587,9 +661,12 @@ setup_scala_toolchain(
 )
 ```
 
-This worked under `WORKSPACE`, but broke under Bzlmod, the error message
-indicating that the builtin `@org_scala_sbt_compiler_interface` toolchain jar
-isn't visible:
+`setup_scala_toolchains` is a macro that can take user specified classpath
+targets as described in [docs/scala_toolchain.md](./docs/scala_toolchain.md).
+Without explicit `*_classpath` or `*_deps` arguments, `setup_scala_toolchain()`
+defaults to using dependency repositories generated by `rules_scala` itself.
+This worked under `WORKSPACE`, but breaks under Bzlmod, because the builtin
+toolchain dependency repos are no longer in the project's scope by default:
 
 ```txt
 ERROR: no such package
@@ -600,20 +677,12 @@ ERROR: no such package
     No repository visible as '@org_scala_sbt_compiler_interface_3_3_5'
 ```
 
-`setup_scala_toolchains` is a macro that can take user specified classpath
-targets as described in [docs/scala_toolchain.md](./docs/scala_toolchain.md).
-Otherwise, it _generates new classpath targets_ using the builtin `rules_scala`
-repositories, but these repositories are no longer in the global scope, causing
-the breakage. (A big part of the Bzlmodification work involved enabling
-`rules_scala` to generate and register toolchains _without_ forcing users to
-bring their dependencies into scope.)
-
-One way to fix this specific problem is to call `use_repo` for every such
-repository needed by the toolchain. Another fix, in this case, is to [use
-`scala_toolchain` directly instead](
-https://github.com/michalbogacz/scala-bazel-monorepo/blob/2cac860f386dcaa1c3be56cd25a84b247d335743/BUILD.bazel).
-Its underlying `BUILD` rule uses the builtin toolchain dependencies via existing
-targets visible within `rules_scala`, without forcing users to import them:
+In this case, where the toolchain only sets different compiler options, the best
+fix is to [use `scala_toolchain` directly instead][scala_tc_direct]. Its
+underlying `BUILD` rule uses builtin toolchain dependencies via existing targets
+visible within `rules_scala`, without forcing users to import them:
+
+[scala_tc_direct]: https://github.com/michalbogacz/scala-bazel-monorepo/blob/2cac860f386dcaa1c3be56cd25a84b247d335743/BUILD.bazel
 
 ```py
 load("@rules_scala//scala:scala_toolchain.bzl", "scala_toolchain")
@@ -635,6 +704,12 @@ toolchain(
 )
 ```
 
+A big part of the Bzlmodification work involved enabling `rules_scala` to
+generate and register toolchains _without_ forcing users to bring their
+dependencies into scope. However, another way to fix this specific problem is to
+call `use_repo` for every builtin repository needed by the
+`setup_scala_toolchain()` call.
+
 ## Breaking changes coming in `rules_scala` 8.x
 
 __The main objective of 8.x will be to enable existing users to migrate to Bazel

docs/cross-compilation.md

@@ -6,9 +6,8 @@ especially for toolchain and rule developers.
 
 ## Quick start
 
-The `scala_config` module extension (or`WORKSPACE` macro) creates the
-`@io_bazel_rules_scala_config` repository. It accepts two parameters that
-specify the the Scala versions supported within the project:
+The `scala_config` module extension (or`WORKSPACE` macro) accepts two parameters
+that specify the the Scala versions supported within the project:
 
 - `scala_version` – a single default version
 - `scala_versions` – a list of versions supported or required by the project
@@ -54,8 +53,6 @@ scala_config(
 )
 ```
 
-
-
 The first parameter, `scala_version`, defines the default version of Scala to
 use when building the project. Values from `scala_versions` can override the
 default in one of two ways:
@@ -90,8 +87,8 @@ one.
 ## Version configuration
 
 The `scala_config` module extension (or `WORKSPACE` macro) creates the
-`@io_bazel_rules_scala_config` repository. Its generated `config.bzl` file
-contains several variables, including:
+`@rules_scala_config` repository. Its generated `config.bzl` file contains
+several variables, including:
 
 - `SCALA_VERSION` – representing the default Scala version, e.g., `"3.3.1"`
 - `SCALA_VERSIONS` – representing all configured Scala versions, e.g.,
@@ -105,8 +102,8 @@ value.
 
 ### `scala_version`
 
-The root package of `@io_bazel_rules_scala_config` defines the following build
-setting (specifically, a ['string_setting()' from '@bazel_skylib'](
+The root package of `@rules_scala_config` defines the following build setting
+(specifically, a ['string_setting()' from '@bazel_skylib'](
 https://github.com/bazelbuild/bazel-skylib/blob/1.7.1/docs/common_settings_doc.md#string_setting)):
 
 ```py
@@ -199,7 +196,7 @@ See the complete documentation in the [scala_cross_version_select.bzl](
 
 ```py
 deps = select({
-    "@io_bazel_rules_scala_config//:scala_version_3_3_1": [...],
+    "@rules_scala_config//:scala_version_3_3_1": [...],
     ...
 })
 ```
@@ -218,15 +215,13 @@ and then `load()` the macro in a `BUILD` file:
 
 ```py
 load(":my_macros.bzl", "srcs")
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSIONS")
 load("@rules_scala//:scala_cross_version.bzl", "version_suffix")
-
-_SCALA_VERSION_SETTING_PREFIX = "@io_bazel_rules_scala_config//:scala_version"
+load("@rules_scala_config//:config.bzl", "SCALA_VERSIONS")
 
 scala_library(
     ...
     srcs = select({
-        SCALA_VERSION_SETTING_PREFIX + version_suffix(v): srcs(v)
+        "@rules_scala_config//:scala_version" + version_suffix(v): srcs(v)
         for v in SCALA_VERSIONS
     }),
     ...
@@ -244,14 +239,14 @@ configured.
 ```py
 def _scala_version_transition_impl(settings, attr):
     if attr.scala_version:
-        return {"@io_bazel_rules_scala_config//:scala_version": attr.scala_version}
+        return {"@rules_scala_config//:scala_version": attr.scala_version}
     else:
         return {}
 
 scala_version_transition = transition(
     implementation = _scala_version_transition_impl,
     inputs = [],
-    outputs = ["@io_bazel_rules_scala_config//:scala_version"],
+    outputs = ["@rules_scala_config//:scala_version"],
 )
 ```
 
@@ -328,7 +323,7 @@ https://bazel.build/reference/be/platforms-and-toolchains#toolchain) rule:
 ```py
 toolchain(
     ...
-    target_settings = ["@io_bazel_rules_scala_config//:scala_version_3_3_1"],
+    target_settings = ["@rules_scala_config//:scala_version_3_3_1"],
     ...
 )
 ```

dt_patches/compiler_sources/extensions.bzl

@@ -1,4 +1,3 @@
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSION")
 load(
     "@rules_scala//scala:scala_cross_version.bzl",
     "default_maven_server_urls",
@@ -15,6 +14,7 @@ load(
     "@rules_scala//third_party/repositories:scala_3_5.bzl",
     _scala_3_version = "scala_version",
 )
+load("@rules_scala_config//:config.bzl", "SCALA_VERSION")
 
 _IS_SCALA_2 = SCALA_VERSION.startswith("2.")
 _IS_SCALA_3 = SCALA_VERSION.startswith("3.")

examples/testing/multi_frameworks_toolchain/BUILD

@@ -3,7 +3,7 @@ load(
     "@rules_scala//testing:testing.bzl",
     "setup_scala_testing_toolchain",
 )
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSION")
+load("@rules_scala_config//:config.bzl", "SCALA_VERSION")
 
 # This example uses the same toolchain deps you'd get from using
 # `scala_toolchains(junit = True, scalatest = True, specs2 = True)`. It's a

jmh/toolchain/toolchain.bzl

@@ -4,7 +4,7 @@ load(
     "//scala:scala_cross_version.bzl",
     _versioned_repositories = "repositories",
 )
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSION")
+load("@rules_scala_config//:config.bzl", "SCALA_VERSION")
 
 DEP_PROVIDERS = [
     "jmh_classpath",

scala/BUILD

@@ -1,7 +1,7 @@
 load("//scala:scala_cross_version.bzl", "version_suffix")
 load("//scala:scala_toolchain.bzl", "scala_toolchain")
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSION")
 load("@rules_java//java:defs.bzl", "java_import", "java_library")
+load("@rules_scala_config//:config.bzl", "SCALA_VERSION")
 
 toolchain_type(
     name = "toolchain_type",

scala/private/macros/scala_repositories.bzl

@@ -5,7 +5,7 @@ load(
     "version_suffix",
 )
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSIONS")
+load("@rules_scala_config//:config.bzl", "SCALA_VERSIONS")
 
 def _dt_patched_compiler_impl(rctx):
     # Need to give the file a .zip extension so rctx.extract knows what type of archive it is
@@ -31,7 +31,7 @@ _COMPILER_SOURCE_ALIAS_TEMPLATE = """alias(
 """
 
 _COMPILER_SOURCES_ENTRY_TEMPLATE = """
-        "@io_bazel_rules_scala_config//:scala_version{scala_version_suffix}":
+        "@rules_scala_config//:scala_version{scala_version_suffix}":
             "@scala_compiler_source{scala_version_suffix}//:src","""
 
 def _compiler_sources_repo_impl(rctx):

scala/private/macros/setup_scala_toolchain.bzl

@@ -1,7 +1,7 @@
 load("//scala:scala_toolchain.bzl", "scala_toolchain")
 load("//scala:providers.bzl", "declare_deps_provider")
 load("//scala:scala_cross_version.bzl", "repositories", "version_suffix")
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSION")
+load("@rules_scala_config//:config.bzl", "SCALA_VERSION")
 
 def setup_scala_toolchain(
         name,
@@ -98,7 +98,10 @@ def setup_scala_toolchain(
         name = name,
         toolchain = ":%s_impl" % name,
         toolchain_type = Label("//scala:toolchain_type"),
-        target_settings = ["@io_bazel_rules_scala_config//:scala_version" + version_suffix(scala_version)],
+        target_settings = [
+            "@rules_scala_config//:scala_version" +
+            version_suffix(scala_version),
+        ],
         visibility = visibility,
     )
 

scala/scala_cross_version.bzl

@@ -74,14 +74,14 @@ def repositories(scala_version, repos):
 
 def _scala_version_transition_impl(settings, attr):
     if attr.scala_version:
-        return {"@io_bazel_rules_scala_config//:scala_version": attr.scala_version}
+        return {"@rules_scala_config//:scala_version": attr.scala_version}
     else:
         return {}
 
 scala_version_transition = transition(
     implementation = _scala_version_transition_impl,
     inputs = [],
-    outputs = ["@io_bazel_rules_scala_config//:scala_version"],
+    outputs = ["@rules_scala_config//:scala_version"],
 )
 
 toolchain_transition_attr = {

scala/scala_cross_version_select.bzl

@@ -1,5 +1,5 @@
-load("@io_bazel_rules_scala_config//:config.bzl", "SCALA_VERSIONS")
 load(":scala_cross_version.bzl", "version_suffix")
+load("@rules_scala_config//:config.bzl", "SCALA_VERSIONS")
 
 def select_for_scala_version(default = [], **kwargs):
     """
@@ -41,7 +41,7 @@ def select_for_scala_version(default = [], **kwargs):
     """
 
     return select({
-        "@io_bazel_rules_scala_config//:scala_version" + version_suffix(scala_version): _matches_for_version(scala_version, kwargs, default)
+        "@rules_scala_config//:scala_version" + version_suffix(scala_version): _matches_for_version(scala_version, kwargs, default)
         for scala_version in SCALA_VERSIONS
     })