Parallel development without the headaches using Git worktree

The real problem for parallel dev is ensuring parallel dev environments can seamlessly co-exist without treading on each other. As soon as one of them wants to open a port, talk to an external database or write to a shared location as part of testing you have them conflicting with each other.

Much of this is a legacy dev issue where there was never so much of an assumption that parallel ephemeral dev environments would be in play in the first place. But legacy dev is still most of dev.

My mind inserted an 'of' in the title. I thought the article was about doing parallel development without using Git worktrees. Prior to AI, I never used worktrees. Now I use them all the time. I think it's both due to that AI agents are well suited to do parallel development, but also due to that Claude helps me avoiding the headaches of using Git worktrees

I use git worktrees daily. I'm surprised by how hard it can be to explain them to people who have never used them. Lately I've settled on "like clones, but sharing a .git directory." The article tries to get this across by comparing them to branches, but I think clones are a more intuitive concept to compare against.

To solve some of the ergonomics issues (command verbosity, manual commands to copy over .env files and install dependencies), I wrote autowt, which is a lightweight but powerful worktree manager: https://steveasleep.com/autowt/

Once I dialed in the cli experience, I basically stopped typing 'git checkout <branch>' to change tasks, because it's easier to ignore working directory state when flipping between tasks.

Having gone down the worktree rabbit hole for a month or so, I am giving up in favor of multiple checkouts to enable many agents to work across many repos.

Worktrees worked great for me when my agents' work was mostly contained to a single repo (they got me to finally hitting rate limits, not that that was a goal). As my homelab scales, agents increasingly work across multiple repos, and that's where (my approach to) worktrees broke down; agents were spawned in a repo worktree and so avoided stepping on the toes of other agents in the same repo without any special instruction, but as soon as they needed to touch another repo, they would default to working in that repo directly, without a worktree, and thus collide with other agents, and muddy a merge process that expected the main repo clone to be clean (which turns out to have been an unnecessary design quirk, but resolving it would still not stop agents from stepping on each other's toes in secondary repos).

After a detour through ZFS dataset clones and some mounting magic that made /srv/src/ appear to be a distinct hierarchy for each agent process, I am simplifying even further and giving each agent a bare directory (sth like /srv/dev/<slug>/) where they can check out any repos they want. The git remote (/srv/git/) becomes the only integration point.

Maybe I should just bite the bullet and move into containers, but performant as they are the ergonomics still bum me out.

Edit: I may actually hold on to ZFS datasets with mounting magic. It does add a bit of complexity to dev tools, but it also reduces path-based trust bloat in harness configs, provides some interesting zfs features (zfs diff, etc)... And it's done.

What a peculiar title. The title suggest parallel dev without using worktrees, but the article is about using worktrees.