"""note_attachments.sha256 (M8 sync hub, step 5 — attachment blob sync)

Revision ID: 0018
Revises: 0017
Create Date: 2026-07-23

A content hash so a native client can tell which attachment blobs it already has
(dedupe) and verify integrity after downloading. Nullable; existing rows are left
un-hashed (no backfill — the file bytes may not be reachable at migration time).
"""
from alembic import op
import sqlalchemy as sa

revision = "0018"
down_revision = "0017"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column("note_attachments", sa.Column("sha256", sa.Text(), nullable=True))


def downgrade() -> None:
    op.drop_column("note_attachments", "sha256")