Motivations

When will we know the time is right? What will push us over the edge?

We are building up technical debt (concerns or issues or solutions are put off because it would be a breaking change requiring a Pulp 4)
- Self fulfilling prophecy (making migration/upgrade more painful)

Thought experiment

if we did a release a new X release, what are the things that would need to change to make this happen?
Note: we aren't suggesting time based features, just force us to think about what things need to change in order to start putting out a roadmap where 1 thing can be picked as the Pulp 4 release

Whatever goes into Pulp4 how will it be painful for our integrators/stakeholders/developers?
Let's gather the superset of ideas for breaking changes and then select what we can afford to deliver in Pulp4.

Took a long time to deliver
Integrators had to put in huge effort to switch
Developers having to split brian between the old and new version.
The way you stood up the "old" version and the "new" version were totally different. Hard to maintain two environments.
Too many changes (tech stack, dev environment)
get management buy in first
We had to adapt downstream user (Katello) workflows to a completely new workflow (multiple repositories -> one repository many repository versions, specifically). Doing so was a massive bear and made the migration so much worse.
- A more straightforwards tech stack transition for Pulp 3 without as radical architectural changes (repo versions) would maybe have been preferable - delivered faster and migrated to more quickly

don't release so often
don't have Pulp 4 be a separate application that has to stand up separately
- parallel APIs within the same application
- or at least shared workers / content app?
do as much as we can in Pulp 3 to get close to the ideal, so that Pulp 3 is as small of a change as possible
- e.g. introducing new APIs

We perhaps made some things a bit too flexible in Pulp 3 - e.g. syncing arbitrary remotes against arbitrary repos.
- Which then made our APIs more complicated by default for things that could and should be simple.
- https://github.com/pulp/pulpcore/issues/2010
Keep

Does Pulp4 mean package that are 4.y or is it a /v4/ REST API shipped in Pulp 3.y