Regression in generate whl BUILD in 1.4.0-rc0 and later

[emirisman]

🐞 bug report

Affected Rule

generate_whl_library_build_bazel

Is this a regression?

Yes, the exact same configuration works in rules_python 1.3.0.

Description

The whl library BUILD generation has broken templating in rules_python 1.4.0-rc0 and later, leading to templating such as:

external/pip/aiocsv/BUILD.bazel:5:12: error loading package '@@pip_aiocsv//': Unable to find package for @@pip_//:config.bzl: The repository '@@pip_' could not be resolved: Repository '@@pip_' is not defined. and referenced by '@@pip//aiocsv:whl'

Resulting BUILD file:

load("@rules_python//python/private/pypi:whl_library_targets.bzl", "whl_library_targets_from_requires")
load("@pip_//:config.bzl", "target_platforms")
...

notice the templating error at second load

🔬 Minimal Reproduction

Bazel 7.6.1, bzlmod enabled, but rules_python still used via WORKSPACE.

🔥 Exception or Error

external/pip/aiocsv/BUILD.bazel:5:12: error loading package '@@pip_aiocsv//': Unable to find package for @@pip_//:config.bzl: The repository '@@pip_' could not be resolved: Repository '@@pip_' is not defined. and referenced by '@@pip//aiocsv:whl'

🌍 Your Environment

Operating System:

  
observed both on macOS and Linux
  

Output of bazel version:

  
Bazelisk version: 1.26.0
Build label: 7.6.1
Build target: @@//src/main/java/com/google/devtools/build/lib/bazel:BazelServer
Build time: Mon Mar 31 17:11:07 2025 (1743441067)
Build timestamp: 1743441067
Build timestamp as int: 1743441067
  

Rules_python version:

  
1.4.0-rc0 and later
  

Anything else relevant?

Looks like this was introduced in #2781

rules_python/python/private/pypi/generate_whl_library_build_bazel.bzl

Lines 62 to 72 in 9e613d5

	loads = [
	"""load("@rules_python//python/private/pypi:whl_library_targets.bzl", "whl_library_targets_from_requires")""",
	]
	if not kwargs.setdefault("target_platforms", None):
	dep_template = kwargs["dep_template"]
	loads.append(
	"load(\"{}\", \"{}\")".format(
	dep_template.format(name = "", target = "config.bzl"),
	"target_platforms",
	),
	)

[aignas]

Could you please check if #2834 is fixing your issue?

[emirisman]

Could you please check if #2834 is fixing your issue?

Your PR seems to resolve the issue. Thanks for the quick reply!