old_contents: load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
  
  def buildifier_dependencies():
      _maybe(
          http_archive,
          name = "bazel_skylib",
          sha256 = "7363ae6721c1648017e23a200013510c9e71ca69f398d52886ee6af7f26af436",
          strip_prefix = "bazel-skylib-c00ef493869e2966d47508e8625aae723a4a3054",
          url = "https://github.com/bazelbuild/bazel-skylib/archive/c00ef493869e2966d47508e8625aae723a4a3054.tar.gz",  # 2018-12-06
      )
      _maybe(
          http_archive,
          name = "io_bazel",
          sha256 = "f59608e56b0b68fe9b18661ae3d10f6a61aaa5f70ed11f2db52e7bc6db516454",
          strip_prefix = "bazel-0.20.0",
          urls = [
              "http://mirror.bazel.build/github.com/bazelbuild/bazel/archive/0.20.0.tar.gz",
              "https://github.com/bazelbuild/bazel/archive/0.20.0.tar.gz",
          ],
      )
  
  def _maybe(repo_rule, name, **kwargs):
      if name not in native.existing_rules():
          repo_rule(name = name, **kwargs)
  
new_contents: load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
  
  def buildifier_dependencies():
      _maybe(
          http_archive,
          name = "bazel_skylib",
          sha256 = "7363ae6721c1648017e23a200013510c9e71ca69f398d52886ee6af7f26af436",
          strip_prefix = "bazel-skylib-c00ef493869e2966d47508e8625aae723a4a3054",
          url = "https://github.com/bazelbuild/bazel-skylib/archive/c00ef493869e2966d47508e8625aae723a4a3054.tar.gz",  # 2018-12-06
      )
      _maybe(
          http_archive,
          name = "io_bazel",
          sha256 = "6ccb831e683179e0cfb351cb11ea297b4db48f9eab987601c038aa0f83037db4",
          urls = [
              "https://releases.bazel.build/0.21.0/release/bazel-0.21.0-dist.zip",
              "https://github.com/bazelbuild/bazel/releases/download/0.21.0/bazel-0.21.0-dist.zip",
          ],
      )
  
  def _maybe(repo_rule, name, **kwargs):
      if name not in native.existing_rules():
          repo_rule(name = name, **kwargs)
  
subject: Update io_bazel to 0.21.0 (#491)