fix cycle when loading externals

Change-Id: Ie2978cc5e832d08fee2f53608e26d31e09a76e79

example/WORKSPACE.bazel

@@ -2,3 +2,7 @@ local_repository(
     name = "rules_clang_tidy",
     path = "..",
 )
+
+load("@rules_clang_tidy//:dependencies.bzl", "rules_clang_tidy_dependencies")
+
+rules_clang_tidy_dependencies()

private/local_workspace_status.bzl

@@ -2,7 +2,50 @@
 Determines the workspace status used as an input to `apply_fixes` rules.
 """
 
-load("@bazel_skylib//lib:versions.bzl", "versions")
+# we can't load @bazel_skylib yet since this bzl file is loaded in
+# dependencies.bzl (which is responsible for loading @bazel_skylib)
+
+# https://github.com/bazelbuild/bazel-skylib/blob/652c8f0b2817daaa2570b7a3b2147643210f7dc7/lib/versions.bzl
+
+def _extract_version_number(bazel_version):
+    """Extracts the semantic version number from a version string
+
+    Args:
+      bazel_version: the version string that begins with the semantic version
+        e.g. "1.2.3rc1 abc1234" where "abc1234" is a commit hash.
+
+    Returns:
+      The semantic version string, like "1.2.3".
+    """
+    for i in range(len(bazel_version)):
+        c = bazel_version[i]
+        if not (c.isdigit() or c == "."):
+            return bazel_version[:i]
+    return bazel_version
+
+# Parse the bazel version string from `native.bazel_version`.
+# e.g.
+# "0.10.0rc1 abc123d" => (0, 10, 0)
+# "0.3.0" => (0, 3, 0)
+def _parse_bazel_version(bazel_version):
+    """Parses a version string into a 3-tuple of ints
+
+    int tuples can be compared directly using binary operators (<, >).
+
+    For a development build of Bazel, this returns an unspecified version tuple
+    that compares higher than any released version.
+
+    Args:
+      bazel_version: the Bazel version string
+
+    Returns:
+      An int 3-tuple of a (major, minor, patch) version.
+    """
+
+    version = _extract_version_number(bazel_version)
+    if not version:
+        return (999999, 999999, 999999)
+    return tuple([int(n) for n in version.split(".")])
 
 def _setup_status_file(rctx):
     """
@@ -83,7 +126,7 @@ BUILD_WORKSPACE_DIRECTORY = "{workspace_root}"
         executable = False,
     )
 
-    if versions.is_at_least("7.1.0", native.bazel_version):
+    if _parse_bazel_version(native.bazel_version) >= _parse_bazel_version("7.1.0"):
         _setup_status_file(rctx)
     else:
         rctx.file(