Removed no-longer-needed pre_migration codepath.

Removes part of the changes for #7280.

fixes #8166

CHANGES/8166.bugfix

@@ -0,0 +1 @@
+Fixed an edge-case failure in erratum-migration when doing repeated migrations.

pulp_2to3_migration/app/pre_migration.py

@@ -1,7 +1,6 @@
 import logging
 
 from collections import namedtuple
-from datetime import datetime
 
 from django.db import transaction
 from django.db.models import Max, Q
@@ -222,61 +221,6 @@ def pre_migrate_content_type(content_model, mutable_type, lazy_type, premigrate_
             pulp2content.clear()
             existing_count = 0
 
-    # If a content type needs to be associated per-repo, we need to make sure that the
-    # existing content hasn't been associated with a new repo since our last migration,
-    # and if so, we need to go back and create a Pulp2Content for these new relations.
-    if set_pulp2_repo and last_updated:
-        # last_updated is a unix timestamp that sometimes defaults to 0 (if there is no
-        # existing content). If there's no existing content we can just skip this entire
-        # process; otherwise we need to convert it to use in our Django query.
-        last_updated = datetime.utcfromtimestamp(last_updated)
-
-        # This content requires to set pulp 2 repo. E.g. for errata, because 1 pulp2
-        # content unit is converted into N pulp3 content units and repo_id is the only
-        # way to have unique records for those.
-        content_relations = Pulp2RepoContent.objects.filter(
-            pulp2_content_type_id=record._content_type_id,
-            pulp2_repository__not_in_plan=False,
-            pulp2_created__gte=last_updated
-        ).select_related(
-            'pulp2_repository'
-        ).only(
-            'pulp2_repository'
-        )
-
-        mongo_content_qs = content_model.pulp2.objects(
-            id__in=content_relations.values_list('pulp2_unit_id', flat=True))
-        pulp2_content_by_id = {
-            record.id: record for record in mongo_content_qs.only(*mongo_fields).no_cache()
-        }
-
-        for relation in content_relations:
-            record = pulp2_content_by_id[relation.pulp2_unit_id]
-            downloaded = record.downloaded if hasattr(record, 'downloaded') else False
-            item = Pulp2Content(
-                pulp2_id=record.id,
-                pulp2_content_type_id=record._content_type_id,
-                pulp2_last_updated=record._last_updated,
-                pulp2_storage_path=record._storage_path,
-                downloaded=downloaded,
-                pulp2_repo=relation.pulp2_repository
-            )
-            _logger.debug(
-                'Add content item to the list to migrate: {item}'.format(item=item))
-            pulp2content.append(item)
-            pulp2content_pb.total += 1
-            pulp2detail_pb.total += 1
-
-        pulp2content_batch = Pulp2Content.objects.bulk_create(pulp2content,
-                                                              ignore_conflicts=True)
-        pulp2content_pb.done += len(pulp2content_batch)
-        pulp2content_pb.save()
-
-        content_model.pulp_2to3_detail.pre_migrate_content_detail(pulp2content_batch)
-
-        pulp2detail_pb.done += len(pulp2content_batch)
-        pulp2detail_pb.save()
-
     pulp2content_pb.save()
     pulp2detail_pb.save()