Support PEP 345 Project-URL metadata

By including one or more Project-URL entries in PKG-INFO metadata,
PyPI can display helpful hyperlinks in a generic manner. Add support
here to be able to pass it through setup.cfg and setup.py with a
project_urls dict. See the corresponding section of the Core
Metadata Specifications from the Python Packaging User Guide for
details:

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

docs/setuptools.txt

@@ -2406,6 +2406,7 @@ name                                               str
 version                                            attr:, str
 url                             home-page          str
 download_url                    download-url       str
+project_urls                                       dict
 author                                             str
 author_email                    author-email       str
 maintainer                                         str

setup.py

@@ -98,6 +98,11 @@ setup_params = dict(
     long_description_content_type='text/x-rst; charset=UTF-8',
     keywords="CPAN PyPI distutils eggs package management",
     url="https://github.com/pypa/setuptools",
+    project_urls={
+        "Bug Tracker": "https://github.com/pypa/setuptools/issues",
+        "Documentation": "http://setuptools.readthedocs.io/",
+        "Source Code": "https://github.com/pypa/setuptools",
+    },
     src_root=None,
     packages=setuptools.find_packages(exclude=['*.tests']),
     package_data=package_data,

setuptools/command/egg_info.py

@@ -597,6 +597,7 @@ def write_pkg_info(cmd, basename, filename):
         metadata = cmd.distribution.metadata
         metadata.version, oldver = cmd.egg_version, metadata.version
         metadata.name, oldname = cmd.egg_name, metadata.name
+        metadata.project_urls = cmd.distribution.metadata.project_urls
         metadata.long_description_content_type = getattr(
             cmd.distribution,
             'long_description_content_type'

setuptools/config.py

@@ -404,6 +404,7 @@ class ConfigMetadataHandler(ConfigHandler):
         """Metadata item name to parser function mapping."""
         parse_list = self._parse_list
         parse_file = self._parse_file
+        parse_dict = self._parse_dict
 
         return {
             'platforms': parse_list,
@@ -416,6 +417,7 @@ class ConfigMetadataHandler(ConfigHandler):
             'description': parse_file,
             'long_description': parse_file,
             'version': self._parse_version,
+            'project_urls': parse_dict,
         }
 
     def _parse_version(self, value):

setuptools/dist.py

@@ -44,7 +44,7 @@ def write_pkg_file(self, file):
             self.classifiers or self.download_url):
         version = '1.1'
     # Setuptools specific for PEP 345
-    if hasattr(self, 'python_requires'):
+    if hasattr(self, 'python_requires') or self.project_urls:
         version = '1.2'
 
     file.write('Metadata-Version: %s\n' % version)
@@ -57,6 +57,8 @@ def write_pkg_file(self, file):
     file.write('License: %s\n' % self.get_license())
     if self.download_url:
         file.write('Download-URL: %s\n' % self.download_url)
+    for project_url in self.project_urls.items():
+        file.write('Project-URL: %s, %s\n' % project_url)
 
     long_desc_content_type = getattr(
         self,
@@ -327,11 +329,18 @@ class Distribution(Distribution_parse_config_files, _Distribution):
         self.long_description_content_type = attrs.get(
             'long_description_content_type'
         )
+        self.project_urls = attrs.get('project_urls', {})
         self.dependency_links = attrs.pop('dependency_links', [])
         self.setup_requires = attrs.pop('setup_requires', [])
         for ep in pkg_resources.iter_entry_points('distutils.setup_keywords'):
             vars(self).setdefault(ep.name, None)
         _Distribution.__init__(self, attrs)
+
+        # The project_urls attribute may not be supported in distutils, so
+        # prime it here from our value if not automatically set
+        self.metadata.project_urls = getattr(
+            self.metadata, 'project_urls', self.project_urls)
+
         if isinstance(self.metadata.version, numbers.Number):
             # Some people apparently take "version number" too literally :)
             self.metadata.version = str(self.metadata.version)

setuptools/tests/test_config.py

@@ -215,6 +215,22 @@ class TestMetadata:
                 'Programming Language :: Python :: 3.5',
             ]
 
+    def test_dict(self, tmpdir):
+
+        fake_env(
+            tmpdir,
+            '[metadata]\n'
+            'project_urls =\n'
+            '  Link One = https://example.com/one/\n'
+            '  Link Two = https://example.com/two/\n'
+        )
+        with get_dist(tmpdir) as dist:
+            metadata = dist.metadata
+            assert metadata.project_urls == {
+                'Link One': 'https://example.com/one/',
+                'Link Two': 'https://example.com/two/',
+            }
+
     def test_version(self, tmpdir):
 
         _, config = fake_env(

setuptools/tests/test_egg_info.py

@@ -417,6 +417,36 @@ class TestEggInfo(object):
         expected_line = 'Description-Content-Type: text/markdown'
         assert expected_line in pkg_info_lines
 
+    def test_project_urls(self, tmpdir_cwd, env):
+        # Test that specifying a `project_urls` dict to the `setup`
+        # function results in writing multiple `Project-URL` lines to
+        # the `PKG-INFO` file in the `<distribution>.egg-info`
+        # directory.
+        # `Project-URL` is described at https://packaging.python.org
+        #     /specifications/core-metadata/#project-url-multiple-use
+
+        self._setup_script_with_requires(
+            """project_urls={
+                'Link One': 'https://example.com/one/',
+                'Link Two': 'https://example.com/two/',
+                },""")
+        environ = os.environ.copy().update(
+            HOME=env.paths['home'],
+        )
+        code, data = environment.run_setup_py(
+            cmd=['egg_info'],
+            pypath=os.pathsep.join([env.paths['lib'], str(tmpdir_cwd)]),
+            data_stream=1,
+            env=environ,
+        )
+        egg_info_dir = os.path.join('.', 'foo.egg-info')
+        with open(os.path.join(egg_info_dir, 'PKG-INFO')) as pkginfo_file:
+            pkg_info_lines = pkginfo_file.read().split('\n')
+        expected_line = 'Project-URL: Link One, https://example.com/one/'
+        assert expected_line in pkg_info_lines
+        expected_line = 'Project-URL: Link Two, https://example.com/two/'
+        assert expected_line in pkg_info_lines
+
     def test_python_requires_egg_info(self, tmpdir_cwd, env):
         self._setup_script_with_requires(
             """python_requires='>=2.7.12',""")