US07-03: Harden Media and Metadata Edge Cases (#85)

migrations/versions/0015_exif_projections.py

@@ -0,0 +1,42 @@
+"""Durable EXIF projections per asset and stage (US07-03).
+
+Revision ID: 0015_exif_projections
+Revises: 0014_restore_plans
+Create Date: 2026-08-16
+
+The concept's ``exif_projections`` table, added at the point it earns its keep: a
+checkpoint that finds a field it does not own changed must be able to say so after
+a restart. ``state`` is verified | divergent | failed, and only ``verified`` counts
+as a completed metadata stage.
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0015_exif_projections"
+down_revision = "0014_restore_plans"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "exif_projections",
+        sa.Column("asset_id", sa.String(), sa.ForeignKey("assets.id"), primary_key=True),
+        sa.Column("stage", sa.String(), primary_key=True),  # safety | analysis
+        sa.Column("id", sa.String(), nullable=False),
+        sa.Column("projection_version", sa.Integer(), nullable=False, server_default="0"),
+        # What the stage asked for: {"add": [...], "remove": [...]}.
+        sa.Column("desired_json", sa.String(), nullable=True),
+        # Fields outside the stage's ownership that did not survive the write.
+        sa.Column("divergent_fields", sa.String(), nullable=True),
+        sa.Column("result_file_sha256", sa.String(), nullable=True),
+        sa.Column("state", sa.String(), nullable=False),
+        sa.Column("error_code", sa.String(), nullable=True),
+        sa.Column("verified_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("exif_projections")