fix: remove custom parse_utc_iso8601_datetime which doesn't handle mi…

…ssing microseconds

Gave a test failure on CI with the string '2023-07-24T00:24:05+00:00'

CHANGELOG.rst

@@ -14,7 +14,7 @@ Change Log
 Unreleased
 ~~~~~~~~~~
 
-*
+* Removed custom datetime parser in favor of ``datetime.fromisoformat`` which is more robust.
 
 [1.4.0] - 2023-08-07
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

blockstore/apps/bundles/store.py

@@ -18,7 +18,6 @@
 import json
 import logging
 import mimetypes
-import pytz
 
 from django.core.files.base import ContentFile, File
 from django.dispatch import Signal
@@ -317,7 +316,7 @@ def get(self, bundle_uuid: UUID, snapshot_digest: bytes) -> Snapshot:
                 bundle_uuid, snapshot_json.get('links', {})
             ),
             hash_digest=bytes_from_hex_str(snapshot_json['hash_digest']),
-            created_at=parse_utc_iso8601_datetime(snapshot_json['created_at']),
+            created_at=datetime.fromisoformat(snapshot_json['created_at']),
         )
 
     def create(self, bundle_uuid, paths_to_files, links=None):
@@ -476,8 +475,8 @@ def get(self, draft_uuid: UUID) -> StagedDraft:
             base_snapshot=base_snapshot,
             files_to_overwrite=FileInfo.from_json_dict(draft_summary_json['files_to_overwrite']),
             links_to_overwrite=links_to_overwrite,
-            created_at=parse_utc_iso8601_datetime(draft_summary_json['created_at']),
-            updated_at=parse_utc_iso8601_datetime(draft_summary_json['updated_at']),
+            created_at=datetime.fromisoformat(draft_summary_json['created_at']),
+            updated_at=datetime.fromisoformat(draft_summary_json['updated_at']),
         )
 
     def create(self, draft_uuid: UUID, bundle_uuid: UUID, name: str,
@@ -839,23 +838,6 @@ def create_hash(start_data=b''):
     return blake2b(start_data, digest_size=20)
 
 
-def parse_utc_iso8601_datetime(datetime_str):
-    """
-    Create a UTC datetime from a str generated by calling datetime.isoformat()
-
-    Python's datetime module is incapable of parsing the ISO 8601 string output
-    that it itself produces (it can't do timezones with ":" in them), so we need
-    to only parse the part before that and then manually add UTC timezone
-    information into it. This is a hack -- it will ignore whatever timezone is
-    really there and force it to be interpreted as UTC.
-
-    This hack should not be necessary once we move to Python 3.7 and can be
-    replaced with datetime.fromisoformat().
-    """
-    parsed_dt = datetime.strptime(datetime_str, r'%Y-%m-%dT%H:%M:%S.%f+00:00')
-    return pytz.utc.localize(parsed_dt).astimezone(timezone.utc)
-
-
 def bytes_from_hex_str(hex_str):
     """Return bytes given a hexidecimal string representation of binary data."""
     if hex_str is None:

requirements/base.in

@@ -12,5 +12,4 @@ edx-auth-backends
 edx-django-release-util
 edx-django-utils
 mysqlclient
-pytz
 sqlparse

requirements/base.txt

@@ -100,7 +100,6 @@ python3-openid==3.2.0
     # via social-auth-core
 pytz==2023.3
     # via
-    #   -r requirements/base.in
     #   django
     #   djangorestframework
     #   drf-yasg

requirements/local.txt

@@ -315,8 +315,6 @@ python3-openid==3.2.0
     #   social-auth-core
 pytz==2023.3
     # via
-    #   -r requirements/docs.txt
-    #   -r requirements/test.txt
     #   babel
     #   django
     #   djangorestframework

requirements/production.txt

@@ -162,7 +162,6 @@ python3-openid==3.2.0
     #   social-auth-core
 pytz==2023.3
     # via
-    #   -r requirements/base.txt
     #   django
     #   djangorestframework
     #   drf-yasg

requirements/test.txt

@@ -225,7 +225,6 @@ python3-openid==3.2.0
     #   social-auth-core
 pytz==2023.3
     # via
-    #   -r requirements/base.txt
     #   django
     #   djangorestframework
     #   drf-yasg