File deletion handling for scaffold/init --update

Templates change over time: a file that made sense when you first generated your project gets renamed, split up, or just stops being relevant. Most codegen tools treat that evolution as something only a brand-new scaffold run can fix — your existing project just keeps carrying the leftover file forever. And if you'd deleted that file yourself to clean up, the next update used to bring it right back, overwriting the choice you'd already made.

The Problem

atmos scaffold generate --update and atmos init --update compute a three-way merge for every file the template still generates: what changed upstream, layered onto what you've customized locally. But that merge only ever ran for files that exist on both sides. Two real gaps followed from that:

• When the template stopped generating a file, --update never noticed. The stale file just sat there, untouched, on every future update, forever.
• When you deleted a file yourself — because you didn't need it, or you'd replaced it with something else — the next --update silently wrote it straight back, as if your deletion had never happened.

The Fix

--update-strategy=rendered now detects a file the template stopped generating and removes it, but only when your copy still matches exactly what the template last produced. If you'd edited that file since, --update doesn't guess: it surfaces an unresolved conflict instead, the same way a genuine merge conflict does, so you decide whether to keep it or let it go. --update-strategy=tracked can't offer this part safely — there's no reliable way to know which files in your project's own git history actually belonged to the template versus anything else that happened to live there.

Independently of strategy, --update also stops silently overwriting a deletion you made yourself. Both tracked and rendered now check whether a file was previously generated before recreating it, and leave your deletion in place if so. Pass --recreate-deleted to opt back into the old always-recreate behavior — it's deliberately its own flag rather than folded into --force, since --force already means "the template's version wins" for merge conflicts, and tying file recreation to it would make "resolve conflicts manually" and "recreate what I deleted" mutually exclusive. --force does, however, now resolve a deletion conflict the same way it resolves any other: if the template removed a file you'd since edited, --force deletes it anyway instead of leaving you stuck with a conflict only manual cleanup could clear.

How to Use It

# A file the template no longer generates is removed automatically on --update,
# as long as you haven't edited it -- otherwise you'll get a conflict to resolve.
atmos scaffold generate my-template ./my-project --update --update-strategy=rendered

# Recreate a file you deleted instead of leaving the deletion in place.
atmos scaffold generate my-template ./my-project --update --recreate-deleted

# Force past a deletion conflict -- the template's choice (delete it) wins.
atmos scaffold generate my-template ./my-project --update --update-strategy=rendered --force

Get Involved

See the atmos scaffold generate and atmos init docs for the full flag reference. Have feedback on this feature? Open an issue or join the conversation in the Cloud Posse community Slack.