0058_commits_snapshots_global.py
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| 1 | """Make commits and snapshots globally content-addressed — remove repo_id. |
| 2 | |
| 3 | Commits and snapshots are content-addressed objects identified by their SHA-256 |
| 4 | hash alone. They do not belong to any repo. Repo membership is tracked in |
| 5 | separate ref tables (musehub_commit_refs, musehub_snapshot_refs), exactly |
| 6 | mirroring how musehub_object_refs tracks object membership. |
| 7 | |
| 8 | Changes: |
| 9 | - Drop repo_id FK + composite indexes from musehub_commits |
| 10 | - Drop repo_id FK + index from musehub_snapshots |
| 11 | - Create musehub_commit_refs (repo_id, commit_id) |
| 12 | - Create musehub_snapshot_refs (repo_id, snapshot_id) |
| 13 | - Backfill both ref tables from existing rows |
| 14 | """ |
| 15 | |
| 16 | from __future__ import annotations |
| 17 | |
| 18 | import sqlalchemy as sa |
| 19 | from alembic import op |
| 20 | |
| 21 | revision = "0058" |
| 22 | down_revision = "0057" |
| 23 | branch_labels = None |
| 24 | depends_on = None |
| 25 | |
| 26 | |
| 27 | def upgrade() -> None: |
| 28 | # ── 1. Create musehub_commit_refs ──────────────────────────────────────── |
| 29 | op.create_table( |
| 30 | "musehub_commit_refs", |
| 31 | sa.Column("repo_id", sa.String(128), sa.ForeignKey("musehub_repos.repo_id", ondelete="CASCADE"), primary_key=True), |
| 32 | sa.Column("commit_id", sa.String(128), sa.ForeignKey("musehub_commits.commit_id", ondelete="CASCADE"), primary_key=True), |
| 33 | sa.Column("created_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()), |
| 34 | ) |
| 35 | op.create_index("ix_musehub_commit_refs_repo_id", "musehub_commit_refs", ["repo_id"]) |
| 36 | |
| 37 | # ── 2. Create musehub_snapshot_refs ────────────────────────────────────── |
| 38 | op.create_table( |
| 39 | "musehub_snapshot_refs", |
| 40 | sa.Column("repo_id", sa.String(128), sa.ForeignKey("musehub_repos.repo_id", ondelete="CASCADE"), primary_key=True), |
| 41 | sa.Column("snapshot_id", sa.String(128), sa.ForeignKey("musehub_snapshots.snapshot_id", ondelete="CASCADE"), primary_key=True), |
| 42 | sa.Column("created_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()), |
| 43 | ) |
| 44 | op.create_index("ix_musehub_snapshot_refs_repo_id", "musehub_snapshot_refs", ["repo_id"]) |
| 45 | |
| 46 | # ── 3. Backfill commit refs from existing musehub_commits rows ──────────── |
| 47 | op.execute( |
| 48 | """ |
| 49 | INSERT INTO musehub_commit_refs (repo_id, commit_id, created_at) |
| 50 | SELECT repo_id, commit_id, now() |
| 51 | FROM musehub_commits |
| 52 | ON CONFLICT DO NOTHING |
| 53 | """ |
| 54 | ) |
| 55 | |
| 56 | # ── 4. Backfill snapshot refs from existing musehub_snapshots rows ──────── |
| 57 | op.execute( |
| 58 | """ |
| 59 | INSERT INTO musehub_snapshot_refs (repo_id, snapshot_id, created_at) |
| 60 | SELECT repo_id, snapshot_id, now() |
| 61 | FROM musehub_snapshots |
| 62 | ON CONFLICT DO NOTHING |
| 63 | """ |
| 64 | ) |
| 65 | |
| 66 | # ── 5. Drop composite indexes on musehub_commits ───────────────────────── |
| 67 | op.drop_index("ix_musehub_commits_repo_branch", table_name="musehub_commits") |
| 68 | op.drop_index("ix_musehub_commits_repo_timestamp", table_name="musehub_commits") |
| 69 | |
| 70 | # ── 6. Drop repo_id FK + column from musehub_commits ───────────────────── |
| 71 | op.drop_constraint("musehub_commits_repo_id_fkey", "musehub_commits", type_="foreignkey") |
| 72 | op.drop_index("ix_musehub_commits_repo_id", table_name="musehub_commits") |
| 73 | op.drop_column("musehub_commits", "repo_id") |
| 74 | |
| 75 | # ── 7. Drop repo_id FK + column from musehub_snapshots ─────────────────── |
| 76 | op.drop_constraint("musehub_snapshots_repo_id_fkey", "musehub_snapshots", type_="foreignkey") |
| 77 | op.drop_index("ix_musehub_snapshots_repo_id", table_name="musehub_snapshots") |
| 78 | op.drop_column("musehub_snapshots", "repo_id") |
| 79 | |
| 80 | |
| 81 | def downgrade() -> None: |
| 82 | # Re-add repo_id to musehub_snapshots (data loss — refs table is lost) |
| 83 | op.add_column("musehub_snapshots", sa.Column("repo_id", sa.String(128), nullable=True)) |
| 84 | op.create_foreign_key( |
| 85 | "musehub_snapshots_repo_id_fkey", "musehub_snapshots", |
| 86 | "musehub_repos", ["repo_id"], ["repo_id"], ondelete="CASCADE", |
| 87 | ) |
| 88 | op.create_index("ix_musehub_snapshots_repo_id", "musehub_snapshots", ["repo_id"]) |
| 89 | |
| 90 | # Re-add repo_id to musehub_commits |
| 91 | op.add_column("musehub_commits", sa.Column("repo_id", sa.String(128), nullable=True)) |
| 92 | op.create_foreign_key( |
| 93 | "musehub_commits_repo_id_fkey", "musehub_commits", |
| 94 | "musehub_repos", ["repo_id"], ["repo_id"], ondelete="CASCADE", |
| 95 | ) |
| 96 | op.create_index("ix_musehub_commits_repo_id", "musehub_commits", ["repo_id"]) |
| 97 | op.create_index("ix_musehub_commits_repo_branch", "musehub_commits", ["repo_id", "branch"]) |
| 98 | op.create_index("ix_musehub_commits_repo_timestamp","musehub_commits", ["repo_id", "timestamp"]) |
| 99 | |
| 100 | op.drop_index("ix_musehub_snapshot_refs_repo_id", table_name="musehub_snapshot_refs") |
| 101 | op.drop_table("musehub_snapshot_refs") |
| 102 | op.drop_index("ix_musehub_commit_refs_repo_id", table_name="musehub_commit_refs") |
| 103 | op.drop_table("musehub_commit_refs") |