Sync
Regenerate a project from the changed model without losing the work done in it, by merging every file three ways.
Generation writes a draft project once. When the model changes afterwards, appling generate --sync brings the project up to the model and keeps what you, or the AI tools working through the registry, changed in it.
appling generate --sync modelsHow it works
Every generation stores what it produced in the project’s .appling/baseline/: the files and, in .appling/baseline-tasks.json, the registry. Sync then takes three versions of every file:
| Version | Where it comes from |
|---|---|
| base | the baseline of the last generation |
| yours | the project as it is now |
| model | a fresh generation of the current model, in a temporary folder |
| Case | Result |
|---|---|
| you did not change the file | the model’s version replaces it |
| the model did not change the file | your version stays |
| both changed it, in different places | both changes, merged with git merge-file |
| both changed the same lines | the file gets conflict markers (<<<<<<< yours, >>>>>>> model) and the registry a task to resolve them |
| the model adds a file | it is added |
| the model no longer produces a file you did not change | it is removed; if you changed it, it stays |
Afterwards the fresh generation becomes the new baseline. Sync needs git on the PATH.
Before the merge: migrations
Sync first applies the model’s pending migration steps, exactly as --migrate does, so renames reach the database as renames. The files a framework owns as history are never merged; every extension lists them:
| Extension | Not synced |
|---|---|
| Django | */migrations/**, .venv/**, __pycache__, db.sqlite3, uv.lock |
| Ash | deps/**, _build/**, priv/repo/migrations/**, priv/resource_snapshots/**, priv/static/**, mix.lock |
| Go | go.sum |
| Rust | target/**, Cargo.lock |
After a sync that added fields, create their migrations the usual way: uv run python manage.py makemigrations for Django, mix ash.codegen <name> for Ash.
The registry after a sync
The registry comes from the fresh generation, with the work done since the last one kept: an entry you marked done stays done as long as what was missing is still the same, and attempts and notes carry over. New elements arrive as new entries; files with conflict markers get an entry (sync) <file>.