Fix errors with incompatible_disallow_empty_glob (bazel-contrib#315)

gergelyfabian · andyscott · web-flow · commit cd552725122f · 2020-06-24T18:00:24.000-07:00
Allow py_library sources to be empty. If --incompatible_disallow_empty_glob is set then generated py_library targets will fail if there are no .py files. Examples are pymssql==2.1.4 and cx-Oracle==7.2.3. Set `allow_empty = True` for glob(). Bazel issue for incompatible_disallow_empty_glob: bazelbuild/bazel#8195 Co-authored-by: Andy Scott <andyscott@users.noreply.github.com>
diff --git a/packaging/whl.py b/packaging/whl.py
@@ -133,6 +133,13 @@ def _parse_metadata(self, content):
                     help='The set of extras for which to generate library targets.')
 
 def main():
+  """
+  Generate a BUILD file for an unzipped Wheel
+
+  We allow for empty Python sources as for Wheels containing only compiled C code
+  there may be no Python sources whatsoever (e.g. packages written in Cython: like `pymssql`).
+  """
+
   args = parser.parse_args()
   whl = Wheel(args.whl)
 
@@ -148,7 +155,7 @@ def main():
 
 py_library(
     name = "pkg",
-    srcs = glob(["**/*.py"]),
+    srcs = glob(["**/*.py"], allow_empty = True),
     data = glob(["**/*"], exclude=["**/*.py", "**/* *", "BUILD", "WORKSPACE"]),
     # This makes this directory a top-level in the python import
     # search path for anything that depends on this.
