Rename pycross_wheel_library to py_wheel_library and make it work

This patch changes the name of the rule to reflect the fact that it's
not exactly the same as the one in rules_pycross.

I also took this opportunity to delete the superfluous
`namespace_pkgs.py` library (plus test) since we have a nearly
identical version already in the main repo.

I added a test to validate that the rule functions at a basic level.

References: bazelbuild#1360

WORKSPACE

@@ -34,7 +34,7 @@ python_register_multi_toolchains(
     python_versions = MINOR_MAPPING.values(),
 )
 
-load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive", "http_file")
 
 # Used for Bazel CI
 http_archive(
@@ -86,3 +86,14 @@ pip_parse(
 load("@publish_deps//:requirements.bzl", "install_deps")
 
 install_deps()
+
+# This wheel is purely here to validate the wheel extraction code. It's not
+# intended for anything else.
+http_file(
+    name = "wheel_for_testing",
+    downloaded_file_path = "numpy-1.25.2-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl",
+    sha256 = "0d60fbae8e0019865fc4784745814cff1c421df5afee233db6d88ab4f14655a2",
+    urls = [
+        "https://files.pythonhosted.org/packages/50/67/3e966d99a07d60a21a21d7ec016e9e4c2642a86fea251ec68677daf71d4d/numpy-1.25.2-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl",
+    ],
+)

python/pip_install/tools/wheel_installer/BUILD.bazel

@@ -9,6 +9,7 @@ py_library(
         "wheel.py",
         "wheel_installer.py",
     ],
+    visibility = ["//third_party/rules_pycross/pycross/private:__subpackages__"],
     deps = [
         requirement("installer"),
         requirement("pip"),

third_party/rules_pycross/pycross/private/BUILD.bazel

@@ -0,0 +1,35 @@
+# Copyright 2023 Jeremy Volkman. All rights reserved.
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//python:defs.bzl", "py_test")
+load(":wheel_library.bzl", "py_wheel_library")
+
+py_wheel_library(
+    name = "extracted_wheel_for_testing",
+    wheel = "@wheel_for_testing//file",
+)
+
+py_test(
+    name = "py_wheel_library_test",
+    srcs = [
+        "py_wheel_library_test.py",
+    ],
+    data = [
+        ":extracted_wheel_for_testing",
+    ],
+    deps = [
+        "//python/runfiles",
+    ],
+)

third_party/rules_pycross/pycross/private/providers.bzl

@@ -13,17 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Pycross providers."""
+"""Python providers."""
 
-PycrossWheelInfo = provider(
+PyWheelInfo = provider(
     doc = "Information about a Python wheel.",
     fields = {
         "name_file": "File: A file containing the canonical name of the wheel.",
         "wheel_file": "File: The wheel file itself.",
     },
 )
 
-PycrossTargetEnvironmentInfo = provider(
+PyTargetEnvironmentInfo = provider(
     doc = "A target environment description.",
     fields = {
         "file": "The JSON file containing target environment information.",

third_party/rules_pycross/pycross/private/py_wheel_library_test.py

@@ -0,0 +1,48 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+from pathlib import Path
+
+from rules_python.python.runfiles import runfiles
+
+RUNFILES = runfiles.Create()
+
+
+class TestPyWheelLibrary(unittest.TestCase):
+    def setUp(self):
+        self.extraction_dir = Path(
+            RUNFILES.Rlocation(
+                "rules_python/third_party/rules_pycross/pycross/private/extracted_wheel_for_testing"
+            )
+        )
+        self.assertTrue(self.extraction_dir.exists(), self.extraction_dir)
+        self.assertTrue(self.extraction_dir.is_dir(), self.extraction_dir)
+
+    def test_file_presence(self):
+        """Validate that the basic file layout looks good."""
+        for path in (
+            "bin/f2py",
+            "site-packages/numpy.libs/libgfortran-daac5196.so.5.0.0",
+            "site-packages/numpy/dtypes.py",
+            "site-packages/numpy/core/_umath_tests.cpython-311-aarch64-linux-gnu.so",
+        ):
+            print(self.extraction_dir / path)
+            self.assertTrue(
+                (self.extraction_dir / path).exists(), f"{path} does not exist"
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()

third_party/rules_pycross/pycross/private/tools/BUILD.bazel

@@ -13,41 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-load("@rules_python//python:defs.bzl", "py_binary", "py_library", "py_test")
-
-package(default_visibility = ["//visibility:private"])
-
-py_library(
-    name = "namespace_pkgs",
-    srcs = [
-        "namespace_pkgs.py",
-    ],
-)
-
-py_test(
-    name = "namespace_pkgs_test",
-    size = "small",
-    srcs = [
-        "namespace_pkgs_test.py",
-    ],
-    tags = [
-        "unit",
-        # TODO(philsc): Make this work.
-        "manual",
-    ],
-    deps = [
-        ":namespace_pkgs",
-    ],
-)
+load("//python:defs.bzl", "py_binary")
 
 py_binary(
     name = "wheel_installer",
     srcs = ["wheel_installer.py"],
     visibility = ["//visibility:public"],
     deps = [
-        ":namespace_pkgs",
-        # TODO(philsc): Make this work with what's available in rules_python.
-        #"@rules_pycross_pypi_deps_absl_py//:pkg",
-        #"@rules_pycross_pypi_deps_installer//:pkg",
+        "//python/pip_install/tools/wheel_installer:lib",
+        "@pypi__installer//:lib",
     ],
 )