bazel: "foo-bar is not a legal workspace name" error is reported on Bazel@HEAD

It seems that on Bazel@HEAD (e6cce762d846f3915b834c278fcb7fa0072ea530) hyphen character is not accepted any more in workspace name?

/** A collection of global Starlark build API functions that apply to WORKSPACE files. */
public class WorkspaceGlobals implements WorkspaceGlobalsApi {

  // Must start with a letter and can contain letters, numbers, and underscores
  private static final Pattern LEGAL_WORKSPACE_NAME = Pattern.compile("^\\p{Alpha}\\w*$");

Am I missing something? I see these errors:

 $ bazel build org.eclipse.jgit.ssh.apache/...
[...]
ERROR: /home/davido/.cache/bazel/_bazel_davido/e1ee1c2b4d81e57e5c4b6fbb219eece8/external/sshd-osgi/WORKSPACE:2:10: sshd-osgi is not a legal workspace name
ERROR: /home/davido/.cache/bazel/_bazel_davido/e1ee1c2b4d81e57e5c4b6fbb219eece8/external/sshd-sftp/WORKSPACE:2:10: sshd-sftp is not a legal workspace name
ERROR: /home/davido/.cache/bazel/_bazel_davido/e1ee1c2b4d81e57e5c4b6fbb219eece8/external/log-api/WORKSPACE:2:10: log-api is not a legal workspace name
INFO: Analyzed target //org.eclipse.jgit.ssh.apache:ssh-apache (28 packages loaded, 1339 targets configured).
INFO: Found 1 target...

The error is reported for the workspace line, e.g. in external/log-api/WORKSPACE:2:10:

# DO NOT EDIT: automatically generated WORKSPACE file for maven_jar rule
workspace(name = "log-api")

The build still succeeds.