Building a Python distribution in Pants 2.13.0 fails for multiple top-level projects layout

BUILD

@@ -5,3 +5,15 @@
 # `python_requirement_library` target. Refer to
 # https://www.pantsbuild.org/docs/python-third-party-dependencies.
 python_requirements(name="reqs")
+
+python_distribution(
+    name="my-wheel",
+    dependencies=["helloworld:lib"],
+    wheel=True,
+    sdist=False,
+    provides=setup_py(
+        name="helloworld",
+        version="0.0.1",
+        description="A language translator.",
+    ),
+)

helloworld/translator/BUILD

@@ -17,14 +17,14 @@ python_tests(
 # Because this target has no source code, Pants cannot infer dependencies. We depend on `:lib`,
 #  which means we'll include all the non-test Python files in this directory, and any of
 #  their dependencies.
-python_distribution(
-    name="dist",
-    dependencies=[":lib"],
-    wheel=True,
-    sdist=True,
-    provides=setup_py(
-        name="helloworld.translator",
-        version="0.0.1",
-        description="A language translator.",
-    ),
-)
+#python_distribution(
+#    name="dist",
+#    dependencies=[":lib"],
+#    wheel=True,
+#    sdist=True,
+#    provides=setup_py(
+#        name="helloworld.translator",
+#        version="0.0.1",
+#        description="A language translator.",
+#    ),
+#)

pants.toml

@@ -2,7 +2,7 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 [GLOBAL]
-pants_version = "2.12.0"
+pants_version = "2.13.0"
 backend_packages.add = [
   "pants.backend.python",
   "pants.backend.python.lint.docformatter",
@@ -33,7 +33,7 @@ repo_id = "3B1D361B-E9F1-49A8-B761-03DCC41FD58E"
 
 [source]
 # The Python source root is the repo root. See https://www.pantsbuild.org/docs/source-roots.
-root_patterns = ["/"]
+root_patterns = ["/helloworld"]
 
 [python]
 # The default interpreter constraints for code in this repo. Individual targets can override