# BE-PR-010: `feat_task_id` Deprecation & Compatibility Strategy

> Date: 2026-03-30

## Background

The `feat_task_id` column on the `proposes` table was used by the **old** Proposal
Accept flow to store the ID of the single `story/feature` task generated when a
Proposal was accepted.

With the new Essential-based Accept flow (BE-PR-007 / BE-PR-008), accepting a
Proposal now generates **multiple** story tasks (one per Essential), tracked via:
- `Task.source_proposal_id` → FK back to the Proposal
- `Task.source_essential_id` → FK back to the specific Essential

This makes `feat_task_id` obsolete.

## Decision: Retain Column, Deprecate Semantics

| Aspect | Decision |
|--------|----------|
| DB column | **Retained** — no schema migration required now |
| Existing data | Legacy rows with a non-NULL `feat_task_id` continue to expose the value via API |
| New writes | **Prohibited** — new accept flow does NOT write `feat_task_id` |
| API response | Field still present in `ProposalResponse` for backward compat |
| Client guidance | Use `generated_tasks` on the Proposal detail endpoint instead |
| Future removal | Column will be dropped in a future migration once all clients have migrated |

## Read Compatibility

- `GET /projects/{id}/proposals` — returns `feat_task_id` (may be `null`)
- `GET /projects/{id}/proposals/{id}` — returns `feat_task_id` + `generated_tasks[]`
- `PATCH /projects/{id}/proposals/{id}` — `feat_task_id` in request body is silently ignored

## Migration Path for Clients

### Backend consumers
Use `Proposal.generated_tasks` relationship (or query `Task` by `source_proposal_id`).

### Frontend
Replace `propose.feat_task_id` references with the `generated_tasks` array from
the detail endpoint. The detail page should list all generated tasks, not just one.

### CLI
CLI does not reference `feat_task_id`. No changes needed.

## Files Changed

| File | Change |
|------|--------|
| `app/models/proposal.py` | Updated docstring & column comment with deprecation notice |
| `app/schemas/schemas.py` | Marked `feat_task_id` field as deprecated |
| `app/api/routers/proposals.py` | Updated comments; field still serialized read-only |
| `tests/test_propose.py` | Updated accept tests to assert `feat_task_id is None` |

## Frontend References (to be updated in FE-PR-002+)

- `src/types/index.ts:139` — `feat_task_id: string | null`
- `src/pages/ProposeDetailPage.tsx:145,180-181` — displays feat_task_id
- `src/pages/ProposesPage.tsx:83` — displays feat_task_id in list

These will be addressed when the frontend Proposal/Essential tasks are implemented.