Pulp2 to Pulp3 migration fails after upgrade to Katello 3.18.3

Problem:
No declared artifact with relative path “.treeinfo” for content “<Content (pulp_type=rpm.distribution_tree): pk=d3b50e84-e665-4ac5-b15f-7468bfb77b3b>”

Prepare ran for over 4 hours, and then failed with

foreman-maintain content prepare
Running Prepare content for Pulp 3

Prepare content for Pulp 3:
Checking for valid Katello configuraton.
Starting task.
2021-06-30 15:20:43 -0500: Migrating erratum content to Pulp 3 3994/14561Migration failed, You will want to investigate: https://katellod02p.d.carfax.us/foreman_tasks/tasks/b3a0e6d8-891d-4ca3-97ae-5d5e4e1d33fc
rake aborted!
ForemanTasks::TaskError: Task b3a0e6d8-891d-4ca3-97ae-5d5e4e1d33fc: Katello::Errors::Pulp3Error: No declared artifact with relative path “.treeinfo” for content “<Content (pulp_type=rpm.distribution_tree): pk=d3b50e84-e665-4ac5-b15f-7468bfb77b3b>”
/opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.18.3.1/lib/katello/tasks/pulp3_migration.rake:33:in block (2 levels) in <top (required)>' /opt/rh/rh-ruby25/root/usr/share/gems/gems/rake-12.3.3/exe/rake:27:in <top (required)>’
Tasks: TOP => katello:pulp3_migration
(See full trace by running task with --trace)
[FAIL]
Failed executing foreman-rake katello:pulp3_migration, exit status 1

Scenario [Prepare content for Pulp 3] failed.

The following steps ended up in failing state:

[content-prepare]

Resolve the failed steps and rerun
the command. In case the failures are false positives,
use --whitelist=“content-prepare”

Expected outcome:
Pulp migration

Foreman and Proxy versions:
Version 2.3.5

Foreman and Proxy plugin versions:
[foreman-tasks] 3.0.6
[foreman_chef] 0.10.0
[foreman_discovery] 16.3.4
[foreman_docker] 5.0.0
[foreman_remote_execution] 4.2.2
[katello] 3.18.3.1

Distribution and version:
CentOS Linux release 7.9.2009

Other relevant data:

Looks like this issue in this thread: [ContentMigration] Katello::Errors::Pulp3Error

What is your pulpcore version?

# rpm -q python3-pulpcore
python3-pulpcore-3.7.6-1.el7.noarch

Do you have AlmaLinux repositories?

The version is the same as you posted.

rpm -q python3-pulpcore

python3-pulpcore-3.7.6-1.el7.noarch

I am not have AlmaLinux, but we do have CentOS 8 and OracleLinux 7/8. I’m going to try to apply the bug fix mentioned in the link you posted for pulp_2to3_models.py to see if that fixes it.

This resolved my issue. Thank you!