`pip.parse` fails for source-less wheels with dependencies

[hartikainen]

(I diagnosed this with heavy help from Opus.)

🐞 bug report

Affected Rule

pip.parse.

Is this a regression?

Yes, I believe 2.2.0 works, while 2.3.1 fails.

Description

I expected py-spy==0.4.1 to work as a py_library dependency, but observed that whl_library_targets points the wrapper's srcs at an empty source target. Bazel then rejects the wrapper during analysis.

🔬 Minimal Reproduction

See examples/py-spy.

From that directory, run:

bazel test //:py_spy_test

🔥 Exception or Error

... //:srcs does not produce any py_library srcs files (expected .py or .py3)

🌍 Your Environment

Operating System:

macOS 26.5.2 arm64

Output of bazel version:

Build label: 9.2.0

Rules_python version:

2.3.1

Anything else relevant?

The workaround is to stay on 2.2.0. I have a small fix and unit tests on the separate py-spy-fix branch.