Package metadata version 2.4

flit_core/flit_core/common.py

@@ -358,7 +358,7 @@ class Metadata(object):
     license_files = ()
     dynamic = ()
 
-    metadata_version = "2.3"
+    metadata_version = "2.4"
 
     def __init__(self, data):
         data = data.copy()
@@ -427,19 +427,15 @@ def write_metadata_file(self, fp):
         license_expr = getattr(self, self._normalise_field_name("License-Expression"))
         license = getattr(self, self._normalise_field_name("License"))
         if license_expr:
-            # TODO: License-Expression requires Metadata-Version '2.4'
-            # Backfill it to the 'License' field for now
-            # fp.write(u'License-Expression: {}\n'.format(license_expr))
-            fp.write(u'License: {}\n'.format(license_expr))
-        elif license:
+            fp.write(u'License-Expression: {}\n'.format(license_expr))
+        elif license:  # Deprecated, superseded by License-Expression
             fp.write(u'License: {}\n'.format(license))
 
         for clsfr in self.classifiers:
             fp.write(u'Classifier: {}\n'.format(clsfr))
 
-        # TODO: License-File requires Metadata-Version '2.4'
-        # for file in self.license_files:
-        #     fp.write(u'License-File: {}\n'.format(file))
+        for file in self.license_files:
+            fp.write(u'License-File: {}\n'.format(file))
 
         for req in self.requires_dist:
             normalised_req = self._normalise_requires_dist(req)

flit_core/flit_core/config.py

@@ -658,7 +658,7 @@ def read_pep621_metadata(proj, path) -> LoadedConfig:
                 if not cl.startswith('License :: '):
                     continue
                 raise ConfigError(
-                    "License classifier are deprecated in favor of the license expression. "
+                    "License classifiers are deprecated in favor of the license expression. "
                     "Remove the '{}' classifier".format(cl)
                 )
         md_dict['classifiers'] = proj['classifiers']

flit_core/tests_core/test_common.py

@@ -210,8 +210,8 @@ def test_metadata_2_3_provides_extra(provides_extra, expected_result):
     ('value', 'expected_license', 'expected_license_expression'),
     [
         ({'license': 'MIT'}, 'MIT', None),
-        ({'license_expression': 'MIT'}, 'MIT', None),  # TODO Metadata 2.4
-        ({'license_expression': 'Apache-2.0'}, 'Apache-2.0', None)  # TODO Metadata 2.4
+        ({'license_expression': 'MIT'}, None, 'MIT'),
+        ({'license_expression': 'Apache-2.0'}, None, 'Apache-2.0'),
     ],
 )
 def test_metadata_license(value, expected_license, expected_license_expression):

flit_core/tests_core/test_config.py

@@ -144,7 +144,7 @@ def test_bad_include_paths(path, err_match):
     # ({'license': "MIT License"}, "Invalid license expression: 'MIT License'"),  # TODO
     (
         {'license': 'MIT', 'classifiers': ['License :: OSI Approved :: MIT License']},
-        "License classifier are deprecated in favor of the license expression",
+        "License classifiers are deprecated in favor of the license expression",
     ),
     ({'license-files': 1}, r"\blist\b"),
     ({'license-files': ["/LICENSE"]}, r"'/LICENSE'.+must not start with '/'"),

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["flit_core >=3.10.1,<4"]
+requires = ["flit_core >=3.11,<4"]
 build-backend = "flit_core.buildapi"
 
 [project]
@@ -16,9 +16,9 @@ dependencies = [
 ]
 requires-python = ">=3.8"
 readme = "README.rst"
-license = {file = "LICENSE"}
+license = "BSD-3-Clause"
+license-files = ["LICENSE"]
 classifiers = ["Intended Audience :: Developers",
-    "License :: OSI Approved :: BSD License",
     "Programming Language :: Python :: 3",
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]