feat(py_wheel): Add support for specifying Project-URL in METADATA (#1276)

`Project-URL` is a field available in core metadata since version 1.2,
which allows specifying additional URLs and display as Project Links in
PyPI package web page.


https://packaging.python.org/en/latest/specifications/core-metadata/#project-url-multiple-use

This change adds the support to specify that.

Author: sfc-gh-wzhao

docs/packaging.md

@@ -157,6 +157,10 @@ py_wheel(
     },
     homepage = "www.example.com",
     license = "Apache 2.0",
+    project_urls = {
+        "Bug Tracker": "www.example.com/issues",
+        "Documentation": "www.example.com/docs",
+    },
     python_tag = "py3",
     # Requirements embedded into the wheel metadata.
     requires = ["pytest"],

examples/wheel/BUILD.bazel

@@ -99,7 +99,7 @@ def test_customized_wheel(self):
                 record_contents,
                 # The entries are guaranteed to be sorted.
                 b"""\
-example_customized-0.0.1.dist-info/METADATA,sha256=vRiyyV45PC5fzK_40nSTtIn3yYzDdsbBAbUvkZiRyc8,461
+example_customized-0.0.1.dist-info/METADATA,sha256=QYQcDJFQSIqan8eiXqL67bqsUfgEAwf2hoK_Lgi1S-0,559
 example_customized-0.0.1.dist-info/NOTICE,sha256=Xpdw-FXET1IRgZ_wTkx1YQfo1-alET0FVf6V1LXO4js,76
 example_customized-0.0.1.dist-info/README,sha256=WmOFwZ3Jga1bHG3JiGRsUheb4UbLffUxyTdHczS27-o,40
 example_customized-0.0.1.dist-info/RECORD,,
@@ -131,6 +131,8 @@ def test_customized_wheel(self):
 License: Apache 2.0
 Description-Content-Type: text/markdown
 Summary: A one-line summary of this test package
+Project-URL: Bug Tracker, www.example.com/issues
+Project-URL: Documentation, www.example.com/docs
 Classifier: License :: OSI Approved :: Apache Software License
 Classifier: Intended Audience :: Developers
 Requires-Dist: pytest

examples/wheel/wheel_test.py

@@ -176,6 +176,11 @@ _other_attrs = {
         doc = "A string specifying the license of the package.",
         default = "",
     ),
+    "project_urls": attr.string_dict(
+        doc = ("A string dict specifying additional browsable URLs for the project and corresponding labels, " +
+               "where label is the key and url is the value. " +
+               'e.g `{{"Bug Tracker": "http://bitbucket.org/tarek/distribute/issues/"}}`'),
+    ),
     "python_requires": attr.string(
         doc = (
             "Python versions required by this distribution, e.g. '>=3.5,<3.7'"
@@ -191,6 +196,7 @@ _other_attrs = {
     ),
 }
 
+_PROJECT_URL_LABEL_LENGTH_LIMIT = 32
 _DESCRIPTION_FILE_EXTENSION_TO_TYPE = {
     "md": "text/markdown",
     "rst": "text/x-rst",
@@ -301,6 +307,11 @@ def _py_wheel_impl(ctx):
     if ctx.attr.summary:
         metadata_contents.append("Summary: %s" % ctx.attr.summary)
 
+    for label, url in sorted(ctx.attr.project_urls.items()):
+        if len(label) > _PROJECT_URL_LABEL_LENGTH_LIMIT:
+            fail("`label` {} in `project_urls` is too long. It is limited to {} characters.".format(len(label), _PROJECT_URL_LABEL_LENGTH_LIMIT))
+        metadata_contents.append("Project-URL: %s, %s" % (label, url))
+
     for c in ctx.attr.classifiers:
         metadata_contents.append("Classifier: %s" % c)
 

python/private/py_wheel.bzl

@@ -0,0 +1,18 @@
+# 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.
+"""Tests for py_wheel."""
+
+load(":py_wheel_tests.bzl", "py_wheel_test_suite")
+
+py_wheel_test_suite(name = "py_wheel_tests")

tools/build_defs/python/tests/py_wheel/BUILD.bazel

@@ -0,0 +1,39 @@
+"""Test for py_wheel."""
+
+load("@rules_testing//lib:analysis_test.bzl", "analysis_test")
+load("@rules_testing//lib:truth.bzl", "matching")
+load("@rules_testing//lib:util.bzl", rt_util = "util")
+load("//python:packaging.bzl", "py_wheel")
+load("//tools/build_defs/python/tests:util.bzl", pt_util = "util")
+
+_tests = []
+
+def _test_too_long_project_url_label(name, config):
+    rt_util.helper_target(
+        config.rule,
+        name = name + "_wheel",
+        distribution = name + "_wheel",
+        python_tag = "py3",
+        version = "0.0.1",
+        project_urls = {"This is a label whose length is above the limit!": "www.example.com"},
+    )
+    analysis_test(
+        name = name,
+        target = name + "_wheel",
+        impl = _test_too_long_project_url_label_impl,
+        expect_failure = True,
+    )
+
+def _test_too_long_project_url_label_impl(env, target):
+    env.expect.that_target(target).failures().contains_predicate(
+        matching.str_matches("in `project_urls` is too long"),
+    )
+
+_tests.append(_test_too_long_project_url_label)
+
+def py_wheel_test_suite(name):
+    config = struct(rule = py_wheel, base_test_rule = py_wheel)
+    native.test_suite(
+        name = name,
+        tests = pt_util.create_tests(_tests, config = config),
+    )