Experimental: add starlarklibrary gazelle extension

cmd/gazelle/BUILD.bazel

@@ -29,6 +29,7 @@ go_library(
         "//cmd/gazelle/internal/wspace",
         "//language/proto_go_modules",
         "//language/protobuf",
+        "//language/starlarklibrary",
         "@bazel_gazelle//config:go_default_library",
         "@bazel_gazelle//flag:go_default_library",
         "@bazel_gazelle//label:go_default_library",

cmd/gazelle/langs.go

@@ -21,11 +21,13 @@ import (
 	"github.com/bazelbuild/bazel-gazelle/language/proto"
 	"github.com/stackb/rules_proto/language/proto_go_modules"
 	"github.com/stackb/rules_proto/language/protobuf"
+	"github.com/stackb/rules_proto/language/starlarklibrary"
 )
 
 var languages = []language.Language{
 	proto.NewLanguage(),
 	protobuf.NewLanguage(),
 	golang.NewLanguage(),
 	proto_go_modules.NewLanguage(),
+	starlarklibrary.NewLanguage(),
 }

extensions/starlark_repository.bzl

@@ -0,0 +1,90 @@
+"""proto_repostitory.bzl provides the starlark_repository rule."""
+
+# Copyright 2014 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("@bazel_features//:features.bzl", "bazel_features")
+load("@build_stack_rules_proto//rules/proto:starlark_repository.bzl", "starlark_repository_attrs", starlark_repository_repo_rule = "starlark_repository")
+
+def _extension_metadata(
+        module_ctx,
+        *,
+        root_module_direct_deps = None,
+        root_module_direct_dev_deps = None,
+        reproducible = False):
+    """returns the module_ctx.extension_metadata in a bazel-version-aware way
+
+    This function was copied from the bazel-gazelle repository.
+    """
+
+    if not hasattr(module_ctx, "extension_metadata"):
+        return None
+    metadata_kwargs = {}
+    if bazel_features.external_deps.extension_metadata_has_reproducible:
+        metadata_kwargs["reproducible"] = reproducible
+    return module_ctx.extension_metadata(
+        root_module_direct_deps = root_module_direct_deps,
+        root_module_direct_dev_deps = root_module_direct_dev_deps,
+        **metadata_kwargs
+    )
+
+def _starlark_repository_impl(module_ctx):
+    # named_repos is a dict<K,V> where V is the kwargs for the actual
+    # "starlark_repository" repo rule and K is the tag.name (the name given by the
+    # MODULE.bazel author)
+    named_archives = {}
+
+    # iterate all the module tags and gather a list of named_archives.
+    #
+    # TODO(pcj): what is the best practice for version selection here? Do I need
+    # to check if module.is_root and handle that differently?
+    #
+    for module in module_ctx.modules:
+        for tag in module.tags.archive:
+            kwargs = {
+                attr: getattr(tag, attr)
+                for attr in _starlark_repository_archive_attrs.keys()
+                if hasattr(tag, attr)
+            }
+            named_archives[tag.name] = kwargs
+
+    # declare a repository rule foreach one
+    for apparent_name, kwargs in named_archives.items():
+        starlark_repository_repo_rule(
+            apparent_name = apparent_name,
+            **kwargs
+        )
+
+    return _extension_metadata(
+        module_ctx,
+        reproducible = True,
+    )
+
+_starlark_repository_archive_attrs = starlark_repository_attrs | {
+    "name": attr.string(
+        doc = "The repo name.",
+        mandatory = True,
+    ),
+}
+_starlark_repository_archive_attrs.pop("apparent_name")
+
+starlark_repository = module_extension(
+    implementation = _starlark_repository_impl,
+    tag_classes = dict(
+        archive = tag_class(
+            doc = "declare an http_archive repository that is post-processed by a custom version of gazelle that includes the 'protobuf' language",
+            attrs = _starlark_repository_archive_attrs,
+        ),
+    ),
+)

language/starlarklibrary/BUILD.bazel

@@ -0,0 +1,33 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "starlarklibrary",
+    srcs = ["language.go"],
+    importpath = "github.com/stackb/rules_proto/language/starlarklibrary",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@bazel_gazelle//config:go_default_library",
+        "@bazel_gazelle//label:go_default_library",
+        "@bazel_gazelle//language:go_default_library",
+        "@bazel_gazelle//pathtools:go_default_library",
+        "@bazel_gazelle//repo:go_default_library",
+        "@bazel_gazelle//resolve:go_default_library",
+        "@bazel_gazelle//rule:go_default_library",
+        "@com_github_bazelbuild_buildtools//build:go_default_library",
+    ],
+)
+
+go_test(
+    name = "starlarklibrary_test",
+    srcs = [
+        "bazelignore_test.go",
+        "dict_test.go",
+        "lifecycle_test.go",
+        "starlark_library_test.go",
+    ],
+    embed = [":starlarklibrary"],
+    deps = [
+        "@bazel_gazelle//config:go_default_library",
+        "@com_github_bazelbuild_buildtools//build:go_default_library",
+    ],
+)