diff --git a/swh/loader/package/pypi/loader.py b/swh/loader/package/pypi/loader.py
index adba58f..ca7bc2b 100644
--- a/swh/loader/package/pypi/loader.py
+++ b/swh/loader/package/pypi/loader.py
@@ -1,236 +1,236 @@
 # Copyright (C) 2019-2021  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import json
 import logging
 import os
 from typing import Any, Dict, Iterator, Optional, Sequence, Tuple
 from urllib.parse import urlparse
 
 import attr
 from pkginfo import UnpackedSDist
 
 from swh.loader.package.loader import (
     BasePackageInfo,
     PackageLoader,
     PartialExtID,
     RawExtrinsicMetadataCore,
 )
 from swh.loader.package.utils import EMPTY_AUTHOR, api_info, cached_method, release_name
 from swh.model.hashutil import hash_to_bytes
 from swh.model.model import (
     MetadataAuthority,
     MetadataAuthorityType,
     Person,
     Revision,
     RevisionType,
     Sha1Git,
     TimestampWithTimezone,
 )
 from swh.storage.interface import StorageInterface
 
 logger = logging.getLogger(__name__)
 
 
 EXTID_TYPE = "pypi-archive-sha256"
 
 
 @attr.s
 class PyPIPackageInfo(BasePackageInfo):
     raw_info = attr.ib(type=Dict[str, Any])
 
     comment_text = attr.ib(type=Optional[str])
     sha256 = attr.ib(type=str)
     upload_time = attr.ib(type=str)
 
     @classmethod
     def from_metadata(cls, metadata: Dict[str, Any]) -> "PyPIPackageInfo":
         return cls(
             url=metadata["url"],
             filename=metadata["filename"],
             raw_info=metadata,
             comment_text=metadata.get("comment_text"),
             sha256=metadata["digests"]["sha256"],
             upload_time=metadata["upload_time"],
             directory_extrinsic_metadata=[
                 RawExtrinsicMetadataCore(
                     format="pypi-project-json", metadata=json.dumps(metadata).encode(),
                 )
             ],
         )
 
     def extid(self) -> PartialExtID:
         return (EXTID_TYPE, hash_to_bytes(self.sha256))
 
 
 class PyPILoader(PackageLoader[PyPIPackageInfo]):
     """Load pypi origin's artifact releases into swh archive.
 
     """
 
     visit_type = "pypi"
 
     def __init__(
         self,
         storage: StorageInterface,
         url: str,
         max_content_size: Optional[int] = None,
     ):
         super().__init__(storage=storage, url=url, max_content_size=max_content_size)
         self.provider_url = pypi_api_url(self.url)
 
     @cached_method
     def _raw_info(self) -> bytes:
         return api_info(self.provider_url)
 
     @cached_method
     def info(self) -> Dict:
         """Return the project metadata information (fetched from pypi registry)
 
         """
         return json.loads(self._raw_info())
 
     def get_versions(self) -> Sequence[str]:
         return self.info()["releases"].keys()
 
     def get_default_version(self) -> str:
         return self.info()["info"]["version"]
 
     def get_metadata_authority(self):
         p_url = urlparse(self.url)
         return MetadataAuthority(
             type=MetadataAuthorityType.FORGE,
             url=f"{p_url.scheme}://{p_url.netloc}/",
             metadata={},
         )
 
     def get_package_info(self, version: str) -> Iterator[Tuple[str, PyPIPackageInfo]]:
         res = []
         for meta in self.info()["releases"][version]:
             if meta["packagetype"] != "sdist":
                 continue
             p_info = PyPIPackageInfo.from_metadata(meta)
             res.append((version, p_info))
 
         if len(res) == 1:
             version, p_info = res[0]
             yield release_name(version), p_info
         else:
             for version, p_info in res:
                 yield release_name(version, p_info.filename), p_info
 
     def build_revision(
         self, p_info: PyPIPackageInfo, uncompressed_path: str, directory: Sha1Git
     ) -> Optional[Revision]:
         i_metadata = extract_intrinsic_metadata(uncompressed_path)
         if not i_metadata:
             return None
 
         # from intrinsic metadata
-        name = i_metadata["version"]
+        version = i_metadata.get("version", "")
         _author = author(i_metadata)
 
         # from extrinsic metadata
         message = p_info.comment_text or ""
-        message = "%s: %s" % (name, message) if message else name
+        message = "%s: %s" % (version, message) if message else version
         date = TimestampWithTimezone.from_iso8601(p_info.upload_time)
 
         return Revision(
             type=RevisionType.TAR,
             message=message.encode("utf-8"),
             author=_author,
             date=date,
             committer=_author,
             committer_date=date,
             parents=(),
             directory=directory,
             synthetic=True,
         )
 
 
 def pypi_api_url(url: str) -> str:
     """Compute api url from a project url
 
     Args:
         url (str): PyPI instance's url (e.g: https://pypi.org/project/requests)
         This deals with correctly transforming the project's api url (e.g
         https://pypi.org/pypi/requests/json)
 
     Returns:
         api url
 
     """
     p_url = urlparse(url)
     project_name = p_url.path.rstrip("/").split("/")[-1]
     url = "%s://%s/pypi/%s/json" % (p_url.scheme, p_url.netloc, project_name)
     return url
 
 
 def extract_intrinsic_metadata(dir_path: str) -> Dict:
     """Given an uncompressed path holding the pkginfo file, returns a
        pkginfo parsed structure as a dict.
 
        The release artifact contains at their root one folder. For example:
        $ tar tvf zprint-0.0.6.tar.gz
        drwxr-xr-x root/root         0 2018-08-22 11:01 zprint-0.0.6/
        ...
 
     Args:
 
         dir_path (str): Path to the uncompressed directory
                         representing a release artifact from pypi.
 
     Returns:
         the pkginfo parsed structure as a dict if any or None if
         none was present.
 
     """
     # Retrieve the root folder of the archive
     if not os.path.exists(dir_path):
         return {}
     lst = os.listdir(dir_path)
     if len(lst) != 1:
         return {}
     project_dirname = lst[0]
     pkginfo_path = os.path.join(dir_path, project_dirname, "PKG-INFO")
     if not os.path.exists(pkginfo_path):
         return {}
     pkginfo = UnpackedSDist(pkginfo_path)
     raw = pkginfo.__dict__
     raw.pop("filename")  # this gets added with the ondisk location
     return raw
 
 
 def author(data: Dict) -> Person:
     """Given a dict of project/release artifact information (coming from
        PyPI), returns an author subset.
 
     Args:
         data (dict): Representing either artifact information or
                      release information.
 
     Returns:
         swh-model dict representing a person.
 
     """
     name = data.get("author")
     email = data.get("author_email")
     fullname = None  # type: Optional[str]
 
     if email:
         fullname = "%s <%s>" % (name, email)
     else:
         fullname = name
 
     if not fullname:
         return EMPTY_AUTHOR
 
     if name is not None:
         name = name.encode("utf-8")
 
     if email is not None:
         email = email.encode("utf-8")
 
     return Person(fullname=fullname.encode("utf-8"), name=name, email=email)
diff --git a/swh/loader/package/pypi/tests/test_pypi.py b/swh/loader/package/pypi/tests/test_pypi.py
index 0ca7312..b248840 100644
--- a/swh/loader/package/pypi/tests/test_pypi.py
+++ b/swh/loader/package/pypi/tests/test_pypi.py
@@ -1,811 +1,850 @@
 # Copyright (C) 2019-2021 The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import json
 import os
 from os import path
 from unittest.mock import patch
 
 import pytest
 
 from swh.core.pytest_plugin import requests_mock_datadir_factory
 from swh.core.tarball import uncompress
 from swh.loader.package import __version__
 from swh.loader.package.pypi.loader import (
     PyPILoader,
+    PyPIPackageInfo,
     author,
     extract_intrinsic_metadata,
     pypi_api_url,
 )
 from swh.loader.tests import assert_last_visit_matches, check_snapshot, get_stats
 from swh.model.hashutil import hash_to_bytes
 from swh.model.identifiers import (
     CoreSWHID,
     ExtendedObjectType,
     ExtendedSWHID,
     ObjectType,
 )
 from swh.model.model import (
     MetadataAuthority,
     MetadataAuthorityType,
     MetadataFetcher,
     Person,
     RawExtrinsicMetadata,
     Snapshot,
     SnapshotBranch,
     TargetType,
 )
 from swh.storage.interface import PagedResult
 
 
 @pytest.fixture
 def _0805nexter_api_info(datadir) -> bytes:
     with open(
         os.path.join(datadir, "https_pypi.org", "pypi_0805nexter_json"), "rb",
     ) as f:
         return f.read()
 
 
 def test_pypi_author_basic():
     data = {
         "author": "i-am-groot",
         "author_email": "iam@groot.org",
     }
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b"i-am-groot <iam@groot.org>",
         name=b"i-am-groot",
         email=b"iam@groot.org",
     )
 
     assert actual_author == expected_author
 
 
 def test_pypi_author_empty_email():
     data = {
         "author": "i-am-groot",
         "author_email": "",
     }
     actual_author = author(data)
 
     expected_author = Person(fullname=b"i-am-groot", name=b"i-am-groot", email=b"",)
 
     assert actual_author == expected_author
 
 
 def test_pypi_author_empty_name():
     data = {
         "author": "",
         "author_email": "iam@groot.org",
     }
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b" <iam@groot.org>", name=b"", email=b"iam@groot.org",
     )
 
     assert actual_author == expected_author
 
 
 def test_pypi_author_malformed():
     data = {
         "author": "['pierre', 'paul', 'jacques']",
         "author_email": None,
     }
 
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b"['pierre', 'paul', 'jacques']",
         name=b"['pierre', 'paul', 'jacques']",
         email=None,
     )
 
     assert actual_author == expected_author
 
 
 def test_pypi_author_malformed_2():
     data = {
         "author": "[marie, jeanne]",
         "author_email": "[marie@some, jeanne@thing]",
     }
 
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b"[marie, jeanne] <[marie@some, jeanne@thing]>",
         name=b"[marie, jeanne]",
         email=b"[marie@some, jeanne@thing]",
     )
 
     assert actual_author == expected_author
 
 
 def test_pypi_author_malformed_3():
     data = {
         "author": "[marie, jeanne, pierre]",
         "author_email": "[marie@somewhere.org, jeanne@somewhere.org]",
     }
 
     actual_author = author(data)
 
     expected_author = Person(
         fullname=(
             b"[marie, jeanne, pierre] " b"<[marie@somewhere.org, jeanne@somewhere.org]>"
         ),
         name=b"[marie, jeanne, pierre]",
         email=b"[marie@somewhere.org, jeanne@somewhere.org]",
     )
 
     actual_author == expected_author
 
 
 # configuration error #
 
 
 def test_pypi_api_url():
     """Compute pypi api url from the pypi project url should be ok"""
     url = pypi_api_url("https://pypi.org/project/requests")
     assert url == "https://pypi.org/pypi/requests/json"
 
 
 def test_pypi_api_url_with_slash():
     """Compute pypi api url from the pypi project url should be ok"""
     url = pypi_api_url("https://pypi.org/project/requests/")
     assert url == "https://pypi.org/pypi/requests/json"
 
 
 @pytest.mark.fs
 def test_pypi_extract_intrinsic_metadata(tmp_path, datadir):
     """Parsing existing archive's PKG-INFO should yield results"""
     uncompressed_archive_path = str(tmp_path)
     archive_path = path.join(
         datadir, "https_files.pythonhosted.org", "0805nexter-1.1.0.zip"
     )
     uncompress(archive_path, dest=uncompressed_archive_path)
 
     actual_metadata = extract_intrinsic_metadata(uncompressed_archive_path)
     expected_metadata = {
         "metadata_version": "1.0",
         "name": "0805nexter",
         "version": "1.1.0",
         "summary": "a simple printer of nested lest",
         "home_page": "http://www.hp.com",
         "author": "hgtkpython",
         "author_email": "2868989685@qq.com",
         "platforms": ["UNKNOWN"],
     }
 
     assert actual_metadata == expected_metadata
 
 
 @pytest.mark.fs
 def test_pypi_extract_intrinsic_metadata_failures(tmp_path):
     """Parsing inexistent path/archive/PKG-INFO yield None"""
     tmp_path = str(tmp_path)  # py3.5 work around (PosixPath issue)
     # inexistent first level path
     assert extract_intrinsic_metadata("/something-inexistent") == {}
     # inexistent second level path (as expected by pypi archives)
     assert extract_intrinsic_metadata(tmp_path) == {}
     # inexistent PKG-INFO within second level path
     existing_path_no_pkginfo = path.join(tmp_path, "something")
     os.mkdir(existing_path_no_pkginfo)
     assert extract_intrinsic_metadata(tmp_path) == {}
 
 
 # LOADER SCENARIO #
 
 # "edge" cases (for the same origin) #
 
 
 # no release artifact:
 # {visit full, status: uneventful, no contents, etc...}
 requests_mock_datadir_missing_all = requests_mock_datadir_factory(
     ignore_urls=[
         "https://files.pythonhosted.org/packages/ec/65/c0116953c9a3f47de89e71964d6c7b0c783b01f29fa3390584dbf3046b4d/0805nexter-1.1.0.zip",  # noqa
         "https://files.pythonhosted.org/packages/c4/a0/4562cda161dc4ecbbe9e2a11eb365400c0461845c5be70d73869786809c4/0805nexter-1.2.0.zip",  # noqa
     ]
 )
 
 
 def test_pypi_no_release_artifact(swh_storage, requests_mock_datadir_missing_all):
     """Load a pypi project with all artifacts missing ends up with no snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "uneventful"
     assert actual_load_status["snapshot_id"] is not None
 
     stats = get_stats(swh_storage)
     assert {
         "content": 0,
         "directory": 0,
         "origin": 1,
         "origin_visit": 1,
         "release": 0,
         "revision": 0,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     assert_last_visit_matches(swh_storage, url, status="partial", type="pypi")
 
 
 def test_pypi_fail__load_snapshot(swh_storage, requests_mock_datadir):
     """problem during loading: {visit: failed, status: failed, no snapshot}
 
     """
     url = "https://pypi.org/project/0805nexter"
     with patch(
         "swh.loader.package.pypi.loader.PyPILoader._load_snapshot",
         side_effect=ValueError("Fake problem to fail visit"),
     ):
         loader = PyPILoader(swh_storage, url)
 
         actual_load_status = loader.load()
         assert actual_load_status == {"status": "failed"}
 
         stats = get_stats(loader.storage)
 
         assert {
             "content": 6,
             "directory": 4,
             "origin": 1,
             "origin_visit": 1,
             "release": 0,
             "revision": 2,
             "skipped_content": 0,
             "snapshot": 0,
         } == stats
 
         assert_last_visit_matches(swh_storage, url, status="failed", type="pypi")
 
 
 # problem during loading:
 # {visit: partial, status: uneventful, no snapshot}
 
 
 def test_pypi_release_with_traceback(swh_storage, requests_mock_datadir):
     url = "https://pypi.org/project/0805nexter"
     with patch(
         "swh.loader.package.pypi.loader.PyPILoader.last_snapshot",
         side_effect=ValueError("Fake problem to fail the visit"),
     ):
         loader = PyPILoader(swh_storage, url)
 
         actual_load_status = loader.load()
         assert actual_load_status == {"status": "failed"}
 
         stats = get_stats(swh_storage)
 
         assert {
             "content": 0,
             "directory": 0,
             "origin": 1,
             "origin_visit": 1,
             "release": 0,
             "revision": 0,
             "skipped_content": 0,
             "snapshot": 0,
         } == stats
 
         assert_last_visit_matches(swh_storage, url, status="failed", type="pypi")
 
 
 # problem during loading: failure early enough in between swh contents...
 # some contents (contents, directories, etc...) have been written in storage
 # {visit: partial, status: eventful, no snapshot}
 
 # problem during loading: failure late enough we can have snapshots (some
 # revisions are written in storage already)
 # {visit: partial, status: eventful, snapshot}
 
 # "normal" cases (for the same origin) #
 
 
 requests_mock_datadir_missing_one = requests_mock_datadir_factory(
     ignore_urls=[
         "https://files.pythonhosted.org/packages/ec/65/c0116953c9a3f47de89e71964d6c7b0c783b01f29fa3390584dbf3046b4d/0805nexter-1.1.0.zip",  # noqa
     ]
 )
 
 # some missing release artifacts:
 # {visit partial, status: eventful, 1 snapshot}
 
 
 def test_pypi_revision_metadata_structure(
     swh_storage, requests_mock_datadir, _0805nexter_api_info
 ):
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     expected_revision_id = hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21")
     revision = swh_storage.revision_get([expected_revision_id])[0]
     assert revision is not None
 
     revision_swhid = CoreSWHID(
         object_type=ObjectType.REVISION, object_id=expected_revision_id
     )
     directory_swhid = ExtendedSWHID(
         object_type=ExtendedObjectType.DIRECTORY, object_id=revision.directory
     )
     metadata_authority = MetadataAuthority(
         type=MetadataAuthorityType.FORGE, url="https://pypi.org/",
     )
     expected_metadata = [
         RawExtrinsicMetadata(
             target=directory_swhid,
             authority=metadata_authority,
             fetcher=MetadataFetcher(
                 name="swh.loader.package.pypi.loader.PyPILoader", version=__version__,
             ),
             discovery_date=loader.visit_date,
             format="pypi-project-json",
             metadata=json.dumps(
                 json.loads(_0805nexter_api_info)["releases"]["1.2.0"][0]
             ).encode(),
             origin=url,
             revision=revision_swhid,
         )
     ]
     assert swh_storage.raw_extrinsic_metadata_get(
         directory_swhid, metadata_authority,
     ) == PagedResult(next_page_token=None, results=expected_metadata,)
 
 
 def test_pypi_visit_with_missing_artifact(
     swh_storage, requests_mock_datadir_missing_one
 ):
     """Load a pypi project with some missing artifacts ends up with 1 snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("dd0e4201a232b1c104433741dbf45895b8ac9355")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     stats = get_stats(swh_storage)
 
     assert {
         "content": 3,
         "directory": 2,
         "origin": 1,
         "origin_visit": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_contents = map(
         hash_to_bytes,
         [
             "405859113963cb7a797642b45f171d6360425d16",
             "e5686aa568fdb1d19d7f1329267082fe40482d31",
             "83ecf6ec1114fd260ca7a833a2d165e71258c338",
         ],
     )
 
     assert list(swh_storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(
         hash_to_bytes,
         [
             "b178b66bd22383d5f16f4f5c923d39ca798861b4",
             "c3a58f8b57433a4b56caaa5033ae2e0931405338",
         ],
     )
 
     assert list(swh_storage.directory_missing(expected_dirs)) == []
 
     # {revision hash: directory hash}
     expected_revs = {
         hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"): hash_to_bytes(
             "b178b66bd22383d5f16f4f5c923d39ca798861b4"
         ),  # noqa
     }
     assert list(swh_storage.revision_missing(expected_revs)) == []
 
     expected_snapshot = Snapshot(
         id=hash_to_bytes(expected_snapshot_id),
         branches={
             b"releases/1.2.0": SnapshotBranch(
                 target=hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
                 target_type=TargetType.REVISION,
             ),
             b"HEAD": SnapshotBranch(
                 target=b"releases/1.2.0", target_type=TargetType.ALIAS,
             ),
         },
     )
     check_snapshot(expected_snapshot, storage=swh_storage)
 
     assert_last_visit_matches(
         swh_storage, url, status="partial", type="pypi", snapshot=expected_snapshot_id,
     )
 
 
 def test_pypi_visit_with_1_release_artifact(swh_storage, requests_mock_datadir):
     """With no prior visit, load a pypi project ends up with 1 snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("ba6e158ada75d0b3cfb209ffdf6daa4ed34a227a")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     stats = get_stats(swh_storage)
     assert {
         "content": 6,
         "directory": 4,
         "origin": 1,
         "origin_visit": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_contents = map(
         hash_to_bytes,
         [
             "a61e24cdfdab3bb7817f6be85d37a3e666b34566",
             "938c33483285fd8ad57f15497f538320df82aeb8",
             "a27576d60e08c94a05006d2e6d540c0fdb5f38c8",
             "405859113963cb7a797642b45f171d6360425d16",
             "e5686aa568fdb1d19d7f1329267082fe40482d31",
             "83ecf6ec1114fd260ca7a833a2d165e71258c338",
         ],
     )
 
     assert list(swh_storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(
         hash_to_bytes,
         [
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d",
             "cf019eb456cf6f78d8c4674596f1c9a97ece8f44",
             "b178b66bd22383d5f16f4f5c923d39ca798861b4",
             "c3a58f8b57433a4b56caaa5033ae2e0931405338",
         ],
     )
 
     assert list(swh_storage.directory_missing(expected_dirs)) == []
 
     # {revision hash: directory hash}
     expected_revs = {
         hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"): hash_to_bytes(
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d"
         ),  # noqa
         hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"): hash_to_bytes(
             "b178b66bd22383d5f16f4f5c923d39ca798861b4"
         ),  # noqa
     }
     assert list(swh_storage.revision_missing(expected_revs)) == []
 
     expected_snapshot = Snapshot(
         id=expected_snapshot_id,
         branches={
             b"releases/1.1.0": SnapshotBranch(
                 target=hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/1.2.0": SnapshotBranch(
                 target=hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
                 target_type=TargetType.REVISION,
             ),
             b"HEAD": SnapshotBranch(
                 target=b"releases/1.2.0", target_type=TargetType.ALIAS,
             ),
         },
     )
     check_snapshot(expected_snapshot, swh_storage)
 
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=expected_snapshot_id
     )
 
 
 def test_pypi_multiple_visits_with_no_change(swh_storage, requests_mock_datadir):
     """Multiple visits with no changes results in 1 same snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     snapshot_id = hash_to_bytes("ba6e158ada75d0b3cfb209ffdf6daa4ed34a227a")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": snapshot_id.hex(),
     }
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=snapshot_id
     )
 
     stats = get_stats(swh_storage)
 
     assert {
         "content": 6,
         "directory": 4,
         "origin": 1,
         "origin_visit": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_snapshot = Snapshot(
         id=snapshot_id,
         branches={
             b"releases/1.1.0": SnapshotBranch(
                 target=hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/1.2.0": SnapshotBranch(
                 target=hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
                 target_type=TargetType.REVISION,
             ),
             b"HEAD": SnapshotBranch(
                 target=b"releases/1.2.0", target_type=TargetType.ALIAS,
             ),
         },
     )
     check_snapshot(expected_snapshot, swh_storage)
 
     actual_load_status2 = loader.load()
     assert actual_load_status2 == {
         "status": "uneventful",
         "snapshot_id": actual_load_status2["snapshot_id"],
     }
 
     visit_status2 = assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi"
     )
 
     stats2 = get_stats(swh_storage)
     expected_stats2 = stats.copy()
     expected_stats2["origin_visit"] = 1 + 1
     assert expected_stats2 == stats2
 
     # same snapshot
     assert visit_status2.snapshot == snapshot_id
 
 
 def test_pypi_incremental_visit(swh_storage, requests_mock_datadir_visits):
     """With prior visit, 2nd load will result with a different snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(swh_storage, url)
 
     visit1_actual_load_status = loader.load()
     visit1_stats = get_stats(swh_storage)
     expected_snapshot_id = hash_to_bytes("ba6e158ada75d0b3cfb209ffdf6daa4ed34a227a")
     assert visit1_actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=expected_snapshot_id
     )
 
     assert {
         "content": 6,
         "directory": 4,
         "origin": 1,
         "origin_visit": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == visit1_stats
 
     # Reset internal state
     del loader._cached__raw_info
     del loader._cached_info
 
     visit2_actual_load_status = loader.load()
     visit2_stats = get_stats(swh_storage)
 
     assert visit2_actual_load_status["status"] == "eventful", visit2_actual_load_status
     expected_snapshot_id2 = hash_to_bytes("2e5149a7b0725d18231a37b342e9b7c4e121f283")
     assert visit2_actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id2.hex(),
     }
 
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=expected_snapshot_id2
     )
 
     assert {
         "content": 6 + 1,  # 1 more content
         "directory": 4 + 2,  # 2 more directories
         "origin": 1,
         "origin_visit": 1 + 1,
         "release": 0,
         "revision": 2 + 1,  # 1 more revision
         "skipped_content": 0,
         "snapshot": 1 + 1,  # 1 more snapshot
     } == visit2_stats
 
     expected_contents = map(
         hash_to_bytes,
         [
             "a61e24cdfdab3bb7817f6be85d37a3e666b34566",
             "938c33483285fd8ad57f15497f538320df82aeb8",
             "a27576d60e08c94a05006d2e6d540c0fdb5f38c8",
             "405859113963cb7a797642b45f171d6360425d16",
             "e5686aa568fdb1d19d7f1329267082fe40482d31",
             "83ecf6ec1114fd260ca7a833a2d165e71258c338",
             "92689fa2b7fb4d4fc6fb195bf73a50c87c030639",
         ],
     )
 
     assert list(swh_storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(
         hash_to_bytes,
         [
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d",
             "cf019eb456cf6f78d8c4674596f1c9a97ece8f44",
             "b178b66bd22383d5f16f4f5c923d39ca798861b4",
             "c3a58f8b57433a4b56caaa5033ae2e0931405338",
             "e226e7e4ad03b4fc1403d69a18ebdd6f2edd2b3a",
             "52604d46843b898f5a43208045d09fcf8731631b",
         ],
     )
 
     assert list(swh_storage.directory_missing(expected_dirs)) == []
 
     # {revision hash: directory hash}
     expected_revs = {
         hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"): hash_to_bytes(
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d"
         ),  # noqa
         hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"): hash_to_bytes(
             "b178b66bd22383d5f16f4f5c923d39ca798861b4"
         ),  # noqa
         hash_to_bytes("51247143b01445c9348afa9edfae31bf7c5d86b1"): hash_to_bytes(
             "e226e7e4ad03b4fc1403d69a18ebdd6f2edd2b3a"
         ),  # noqa
     }
 
     assert list(swh_storage.revision_missing(expected_revs)) == []
 
     expected_snapshot = Snapshot(
         id=expected_snapshot_id2,
         branches={
             b"releases/1.1.0": SnapshotBranch(
                 target=hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/1.2.0": SnapshotBranch(
                 target=hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/1.3.0": SnapshotBranch(
                 target=hash_to_bytes("51247143b01445c9348afa9edfae31bf7c5d86b1"),
                 target_type=TargetType.REVISION,
             ),
             b"HEAD": SnapshotBranch(
                 target=b"releases/1.3.0", target_type=TargetType.ALIAS,
             ),
         },
     )
 
     check_snapshot(expected_snapshot, swh_storage)
 
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=expected_snapshot.id
     )
 
     urls = [
         m.url
         for m in requests_mock_datadir_visits.request_history
         if m.url.startswith("https://files.pythonhosted.org")
     ]
     # visited each artifact once across 2 visits
     assert len(urls) == len(set(urls))
 
 
 # release artifact, no new artifact
 # {visit full, status uneventful, same snapshot as before}
 
 # release artifact, old artifact with different checksums
 # {visit full, status full, new snapshot with shared history and some new
 # different history}
 
 # release with multiple sdist artifacts per pypi "version"
 # snapshot branch output is different
 
 
 def test_pypi_visit_1_release_with_2_artifacts(swh_storage, requests_mock_datadir):
     """With no prior visit, load a pypi project ends up with 1 snapshot
 
     """
     url = "https://pypi.org/project/nexter"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("a27e638a4dad6fbfa273c6ebec1c4bf320fb84c6")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     expected_snapshot = Snapshot(
         id=expected_snapshot_id,
         branches={
             b"releases/1.1.0/nexter-1.1.0.zip": SnapshotBranch(
                 target=hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/1.1.0/nexter-1.1.0.tar.gz": SnapshotBranch(
                 target=hash_to_bytes("0bf88f5760cca7665d0af4d6575d9301134fe11a"),
                 target_type=TargetType.REVISION,
             ),
         },
     )
     check_snapshot(expected_snapshot, swh_storage)
 
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=expected_snapshot.id
     )
 
 
 def test_pypi_artifact_with_no_intrinsic_metadata(swh_storage, requests_mock_datadir):
     """Skip artifact with no intrinsic metadata during ingestion
 
     """
     url = "https://pypi.org/project/upymenu"
     loader = PyPILoader(swh_storage, url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("1a8893e6a86f444e8be8e7bda6cb34fb1735a00e")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     # no branch as one artifact without any intrinsic metadata
     expected_snapshot = Snapshot(id=expected_snapshot_id, branches={})
     check_snapshot(expected_snapshot, swh_storage)
 
     assert_last_visit_matches(
         swh_storage, url, status="full", type="pypi", snapshot=expected_snapshot.id
     )
 
 
 def test_pypi_origin_not_found(swh_storage, requests_mock_datadir):
     url = "https://pypi.org/project/unknown"
     loader = PyPILoader(swh_storage, url)
 
     assert loader.load() == {"status": "failed"}
 
     assert_last_visit_matches(
         swh_storage, url, status="not_found", type="pypi", snapshot=None
     )
+
+
+def test_pypi_build_revision_missing_version_in_pkg_info(swh_storage, tmp_path):
+    """Simulate revision build when Version field is missing in PKG-INFO file."""
+    url = "https://pypi.org/project/GermlineFilter"
+    # create package info
+    p_info = PyPIPackageInfo(
+        url=url,
+        filename="GermlineFilter-1.2.tar.gz",
+        directory_extrinsic_metadata=[],
+        raw_info={},
+        comment_text="",
+        sha256="e4982353c544d94b34f02c5690ab3d3ebc93480d5b62fe6f3317f23c515acc05",
+        upload_time="2015-02-18T20:39:13",
+    )
+
+    # create PKG-INFO file with missing Version field
+    package_path = tmp_path / "GermlineFilter-1.2"
+    pkg_info_path = package_path / "PKG-INFO"
+    package_path.mkdir()
+    pkg_info_path.write_text(
+        """Metadata-Version: 1.2
+Name: germline_filter
+Home-page:
+Author: Cristian Caloian (OICR)
+Author-email: cristian.caloian@oicr.on.ca
+License: UNKNOWN
+Description: UNKNOWN
+Platform: UNKNOWN"""
+    )
+    directory = hash_to_bytes("8b864d66f356afe35033d58f8e03b7c23a66751f")
+
+    # attempt to build revision
+    loader = PyPILoader(swh_storage, url)
+    revision = loader.build_revision(p_info, str(tmp_path), directory)
+
+    # without comment_text and version in PKG-INFO, message should be empty
+    assert revision.message == b""