# Backend Branches — `npx @insforge/cli branch`

A branch is a full child of the parent project: own EC2, own PostgreSQL, own storage namespace. It shares the parent's `JWT_SECRET` (same users authenticate) but gets fresh `API_KEY` / `ANON_KEY`. Use it to test schema, RLS, auth, or function changes in isolation before merging back to parent.

Branching is **not free** — each branch consumes an EC2 instance. Use it when isolation pays off.

## When to use a branch

**Strong signals — branch first:**

- Destructive DDL on existing tables (`DROP TABLE`, `DROP COLUMN`, `ALTER COLUMN TYPE`). `git revert` doesn't restore lost data.
- New or modified RLS policies on user-data tables. RLS bugs are silent — prod users lock out or get unintended access.
- Auth provider config changes (OAuth providers, redirect URIs, SMTP). Bricks prod login if wrong.
- Multi-step refactors touching >3 tables or >1 schema.

**Moderate signals — branch if convenient:**

- Adding a new table or column (additive).
- Email templates, AI gateway config, cron schedule changes.

**Skip the branch:**

- Row-data-only changes (insert/update). Branching is about schema, not data.
- Client-side fixes that don't touch the backend.
- Edge-function logic-only changes covered by unit tests.
- Anything `git revert` handles faster.

## Mode selection

| Mode             | When                                                                                                                 |
| ---------------- | -------------------------------------------------------------------------------------------------------------------- |
| `full` (default) | Need realistic data — RLS testing with real rows, query plan tuning, large-table migrations.                         |
| `schema-only`    | Synthetic seed rows are enough. Faster to create. User-data tables (`auth.users`, `storage.objects`, …) start empty. |

Mode is **fixed at create time** — `branch reset` uses the original dump. Need a different mode → delete + recreate.

## Lifecycle commands

### `branch create <name> [--mode full|schema-only] [--no-switch]`

Creates a branch from the linked parent and auto-switches the directory's context to it (unless `--no-switch`). Provisioning takes 30–120 s for small DBs, longer for large.

`<name>`: 1–64 chars, `[a-zA-Z0-9-]`, must start with letter/digit, unique per parent.

After creation:

1. **Re-source your dev server's `.env`** — `INSFORGE_URL` / `INSFORGE_ANON_KEY` change with the switch.
2. **Deploy code that lives outside the database.** `pg_dump` copies `functions.definitions` rows but not the Deno Subhosting bundles, Vercel frontends, or Fly.io compute services — the branch's runtime starts empty. Run `functions deploy <slug>`, `deployments deploy`, and `compute deploy` for anything you need on the branch (`compute deploy`, not `compute update` — there's no service id to update yet). Symptom if you skip this: function invocations fail with `getaddrinfo ENOTFOUND deno` or `Deployment not found`.

### `branch list`

Lists active branches of the parent (or, when on a branch, that branch's siblings). The leading column shows `*` for the branch the directory is currently switched onto.

| State       | Meaning                                                                                                                |
| ----------- | ---------------------------------------------------------------------------------------------------------------------- |
| `creating`  | Provisioning EC2 + restoring pg_dump (30–120 s).                                                                       |
| `ready`     | Usable — can be switched, modified, merged, or reset.                                                                  |
| `merging`   | Merge in progress (usually < 30 s).                                                                                    |
| `merged`    | Last merge succeeded. Dormant — `branch reset` rewinds to T0 and flips back to `ready` so the same slot can be reused. |
| `resetting` | `branch reset` is restoring the T0 dump in place.                                                                      |
| `deleted`   | Soft-delete tombstone (filtered from `list`).                                                                          |

### `branch switch <name>` / `--parent`

Repoints `.insforge/project.json` at the branch (or back at the original parent). Refuses if the target branch isn't `ready`.

> **Critical:** the dev server's `.env` is **not** updated by `switch`. The SDK reads `INSFORGE_URL` / `INSFORGE_ANON_KEY` from `.env`, so without re-sourcing, the SDK silently keeps hitting the previous backend. This is the #1 source of "I switched but my changes aren't showing up."

> **Also:** each backend has its own function / frontend / compute runtime. Switching points the SDK at a different EC2 whose Deno Subhosting, Vercel, and Fly.io state are independent. If you've never deployed your code on the target (e.g. first switch to a freshly-created branch), deploy it with `functions deploy`, `deployments deploy`, and `compute deploy` — otherwise calls land on an empty runtime and fail with `getaddrinfo ENOTFOUND deno` / `Deployment not found`.

The first hop off the parent backs up `.insforge/project.json` to `.insforge/project.parent.json`. Subsequent branch ↔ branch switches don't touch the backup — `--parent` always returns to the original.

### `branch delete <name> [-y]`

Deletes a branch and reclaims its EC2. Auto-`switch --parent` if the directory is currently on the deleted branch. **Irreversible** — branch data is lost. Already-merged branches: deletion still works (the merge has already landed on parent).

## Reset vs. delete + recreate

| Want to…                                                                                              | Reach for                                                                  |
| ----------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------- |
| Rerun the experiment from a clean T0, keep the same `API_KEY` / URL so dev-server config is unchanged | `branch reset`                                                             |
| A different `--mode` (mode is fixed at create time)                                                   | delete + create                                                            |
| A fresh `appkey` / API key so callers can't talk to the old branch                                    | delete + create                                                            |
| Re-merge a branch already in `merged` with new changes layered on T0                                  | `branch reset` (re-opens the slot), make new changes, `branch merge` again |

See [branch reset](reset.md) for what reset does and does not touch.

## Failure modes

| Error                          | Meaning                                                        | Fix                         |
| ------------------------------ | -------------------------------------------------------------- | --------------------------- |
| `branch.quota_exceeded`        | Per-org cap (3 parents) or per-parent cap (2 branches) reached | Delete an old branch first  |
| `branch.parent_not_branchable` | Parent is itself a branch / not active / pre-2.x               | Use a top-level 2.x project |
| `branch.name_conflict`         | Branch name already exists on this parent                      | Pick a different name       |
| `branch.not_found`             | No branch with that name on the parent                         | Check `branch list`         |
| `branch.busy`                  | Branch is `creating` / `merging` / `resetting`                 | Wait for the in-flight op   |
| `branch.not_ready`             | Branch isn't in `ready` state for this op                      | Wait or check state         |

## Limits

- Per-org: max 3 parent projects with active branches (configurable).
- Per-parent: max 2 active branches (configurable).
- Branches do not nest (no branch-of-a-branch).
- Branches do not auto-resume when the parent resumes — resume manually.
- Branches are deleted (cascade) when the parent project is deleted.

## See also

- [branch merge](merge.md) — merging a branch back to parent (dry-run, conflict resolution, what gets applied)
- [branch reset](reset.md) — rewinding a branch to T0 (recovery / re-merge)