Provide Distribution.origin reflecting content of direct_url.json.

importlib_metadata/__init__.py

@@ -3,8 +3,10 @@
 import abc
 import csv
 import sys
+import json
 import zipp
 import email
+import types
 import inspect
 import pathlib
 import operator
@@ -625,6 +627,16 @@ def url_req_space(req):
             space = url_req_space(section.value)
             yield section.value + space + quoted_marker(section.name)
 
+    @property
+    def origin(self):
+        return self._load_json('direct_url.json')
+
+    def _load_json(self, filename):
+        return pass_none(json.loads)(
+            self.read_text(filename),
+            object_hook=lambda data: types.SimpleNamespace(**data),
+        )
+
 
 class DistributionFinder(MetaPathFinder):
     """

newsfragments/404.feature.rst

@@ -0,0 +1 @@
+Added ``Distribution.origin`` supplying the ``direct_url.json`` in a ``SimpleNamespace``.

tests/fixtures.py

@@ -1,6 +1,7 @@
 import os
 import sys
 import copy
+import json
 import shutil
 import pathlib
 import tempfile
@@ -131,6 +132,27 @@ def make_uppercase(self):
         build_files(files, self.site_dir)
 
 
+class DistInfoPkgEditable(DistInfoPkg):
+    """
+    Package with a PEP 660 direct_url.json.
+    """
+
+    some_hash = '524127ce937f7cb65665130c695abd18ca386f60bb29687efb976faa1596fdcc'
+    files: FilesSpec = {
+        'distinfo_pkg-1.0.0.dist-info': {
+            'direct_url.json': json.dumps(
+                {
+                    "archive_info": {
+                        "hash": f"sha256={some_hash}",
+                        "hashes": {"sha256": f"{some_hash}"},
+                    },
+                    "url": "file:///path/to/distinfo_pkg-1.0.0.editable-py3-none-any.whl",
+                }
+            )
+        },
+    }
+
+
 class DistInfoPkgWithDot(OnSysPath, SiteBuilder):
     files: FilesSpec = {
         "pkg_dot-1.0.0.dist-info": {

tests/test_main.py

@@ -457,3 +457,10 @@ def import_names_from_package(package_name):
         # sources_fallback-pkg has one import ('sources_fallback') inferred from
         # SOURCES.txt (top_level.txt and installed-files.txt is missing)
         assert import_names_from_package('sources_fallback-pkg') == {'sources_fallback'}
+
+
+class EditableDistributionTest(fixtures.DistInfoPkgEditable, unittest.TestCase):
+    def test_origin(self):
+        dist = Distribution.from_name('distinfo-pkg')
+        assert dist.origin.url.endswith('.whl')
+        assert dist.origin.archive_info.hashes.sha256