feat: add support for Requires-External metadata

flit_core/flit_core/common.py

@@ -341,6 +341,9 @@ def write_metadata_file(self, fp):
         for extra in self.provides_extra:
             fp.write(u'Provides-Extra: {}\n'.format(extra))
 
+        for ext in self.requires_external:
+            fp.write(u'Requires-External: {}\n'.format(ext))
+
         if self.description is not None:
             fp.write(u'\n' + self.description + u'\n')
 

flit_core/flit_core/config.py

@@ -15,7 +15,8 @@ class ConfigError(ValueError):
 metadata_list_fields = {
     'classifiers',
     'requires',
-    'dev-requires'
+    'dev-requires',
+    'requires-external',
 }
 
 metadata_allowed_fields = {
@@ -305,6 +306,9 @@ def _prep_metadata(md_sect, path):
 
     md_dict['provides_extra'] = sorted(res.reqs_by_extra.keys())
 
+    if 'requires-external' in md_dict:
+        md_dict['requires_external'] = md_dict.pop('requires-external')
+
     # For internal use, record the main requirements as a '.none' extra.
     res.reqs_by_extra['.none'] = reqs_noextra
 

tests/samples/requires-external/module1.py

@@ -0,0 +1,3 @@
+"""Example module"""
+
+__version__ = '0.1'

tests/samples/requires-external/pyproject.toml

@@ -0,0 +1,12 @@
+[build-system]
+requires = ["flit"]
+
+[tool.flit.metadata]
+module = "module1"
+author = "Sir Robin"
+author-email = "robin@camelot.uk"
+home-page = "http://github.com/sirrobin/module1"
+requires-external = [
+    "git",
+    "ffmpeg",
+]

tests/test_wheel.py

@@ -71,6 +71,16 @@ def test_entry_points(copy_sample):
         assert 'console_scripts' in cp.sections()
         assert 'myplugins' in cp.sections()
 
+def test_requires_external(copy_sample):
+    td = copy_sample('requires-external')
+    make_wheel_in(td / 'pyproject.toml', td)
+    assert_isfile(td / 'module1-0.1-py2.py3-none-any.whl')
+    with unpack(td / 'module1-0.1-py2.py3-none-any.whl') as td_unpack:
+        with open(str(Path(td_unpack) / 'module1-0.1.dist-info' / 'METADATA')) as f:
+            txt = f.read()
+            assert 'Requires-External: git' in txt
+            assert 'Requires-External: ffmpeg' in txt
+
 def test_entry_points_conflict(copy_sample):
     td = copy_sample('entrypoints_conflict')
     with pytest.raises(EntryPointsConflict):