fix(migrations): adopt published ledgerless baseline

crates/crank-registry/src/migrations.rs

@@ -11,6 +11,7 @@ mod onboarding_product_events_v11;
 mod owned_relations;
 mod platform_key_name_reuse_v6;
 mod schema_guard;
+mod schema_guard_legacy_v1;
 mod schema_guard_v10;
 mod schema_guard_v11;
 mod schema_guard_v12;

crates/crank-registry/src/migrations/authority.rs

@@ -11,6 +11,9 @@ use super::platform_key_name_reuse_v6;
 use super::schema_guard::{
     OWNED_RELATIONS, relation_exists, validate_required_relations, validate_schema_fingerprint,
 };
+use super::schema_guard_legacy_v1::{
+    validate_ledgerless_baseline_fingerprint, validate_ledgerless_optional_fingerprints,
+};
 use super::{BASELINE_CHECKSUM, BASELINE_VERSION, apply_baseline};
 use crate::ext::ExtensionMigration;
 use sqlx::{PgConnection, PgPool, Row, Transaction, query};
@@ -389,6 +392,19 @@ impl MigrationAuthority {
         if from < 13 {
             artifact_cleanup_indexes_v13::apply(&mut transaction, &Self::sequence()[12]).await?;
         }
+        match inspect(&mut transaction).await? {
+            MigrationPreflight::Current {
+                version: CURRENT_VERSION,
+            } => {}
+            _ => {
+                return Err(MigrationError::new(
+                    "apply_failed",
+                    "apply.postflight",
+                    Some(CURRENT_VERSION),
+                    "restore_known_good_backup",
+                ));
+            }
+        }
         transaction
             .commit()
             .await
@@ -408,6 +424,12 @@ async fn inspect(connection: &mut PgConnection) -> Result<MigrationPreflight, Mi
             owned_exists |= relation_exists(connection, relation).await?;
         }
         if owned_exists {
+            if is_ledgerless_legacy_baseline(connection, canonical_exists).await? {
+                return Ok(MigrationPreflight::MigrationRequired {
+                    current: 0,
+                    target: CURRENT_VERSION,
+                });
+            }
             return Err(MigrationError::new(
                 "partial_sequence",
                 "preflight.core_missing",
@@ -541,6 +563,47 @@ async fn inspect(connection: &mut PgConnection) -> Result<MigrationPreflight, Mi
         Ok(MigrationPreflight::Current { version: current })
     }
 }
+async fn is_ledgerless_legacy_baseline(
+    connection: &mut PgConnection,
+    canonical_exists: bool,
+) -> Result<bool, MigrationError> {
+    if canonical_exists {
+        return Ok(false);
+    }
+    for relation in [
+        "__crank_migration_legacy_audit",
+        "master_key_identities",
+        "master_key_rotations",
+        "admin_bootstrap_contracts",
+        "admin_login_backoff",
+        "admin_security_audit_events",
+        "product_events",
+        "product_event_daily_rollups",
+        "onboarding_selections",
+        "artifact_blobs",
+        "artifact_sources",
+    ] {
+        if relation_exists(connection, relation).await? {
+            return Ok(false);
+        }
+    }
+    for relation in owned_relations::BASELINE {
+        if !relation_exists(connection, relation).await? {
+            return Ok(false);
+        }
+    }
+    validate_required_relations(connection, owned_relations::BASELINE, 1).await?;
+    validate_ledgerless_baseline_fingerprint(connection).await?;
+    let mcp_ledger = relation_exists(connection, "__crank_mcp_migrations").await?;
+    if mcp_ledger {
+        return Ok(false);
+    }
+    let mcp_sessions = relation_exists(connection, "mcp_transport_sessions").await?;
+    let extension_ledger = relation_exists(connection, "__crank_ext_migrations").await?;
+    validate_ledgerless_optional_fingerprints(connection, mcp_sessions, extension_ledger).await?;
+    inspect_optional_legacy_for_ledgerless_baseline(connection).await?;
+    Ok(true)
+}
 async fn validate_core_ledger(connection: &mut PgConnection) -> Result<(), MigrationError> {
     let rows = query("select version, description, checksum from __crank_core_migrations order by version limit 2")
         .fetch_all(connection)
@@ -577,9 +640,21 @@ async fn validate_core_ledger(connection: &mut PgConnection) -> Result<(), Migra
     Ok(())
 }
 async fn inspect_optional_legacy(connection: &mut PgConnection) -> Result<(), MigrationError> {
+    inspect_optional_legacy_with_policy(connection, false).await
+}
+async fn inspect_optional_legacy_for_ledgerless_baseline(
+    connection: &mut PgConnection,
+) -> Result<(), MigrationError> {
+    inspect_optional_legacy_with_policy(connection, true).await
+}
+async fn inspect_optional_legacy_with_policy(
+    connection: &mut PgConnection,
+    allow_sessions_without_ledger: bool,
+) -> Result<(), MigrationError> {
     let mcp_ledger = relation_exists(connection, "__crank_mcp_migrations").await?;
     let mcp_sessions = relation_exists(connection, "mcp_transport_sessions").await?;
-    if mcp_ledger != mcp_sessions {
+    if mcp_ledger != mcp_sessions && !(allow_sessions_without_ledger && !mcp_ledger && mcp_sessions)
+    {
         return Err(MigrationError::new(
             "legacy_conflict",
             "preflight.legacy_mcp",

crates/crank-registry/src/migrations/schema_guard.rs

@@ -325,6 +325,15 @@ pub(super) async fn validate_schema_fingerprint(
             .iter()
             .filter_map(|row| row.try_get::<String, _>("column_name").ok())
             .collect::<Vec<_>>();
+        let required = required
+            .iter()
+            .copied()
+            .filter(|column| {
+                !(current_version == 1
+                    && *table == "__crank_ext_migrations"
+                    && *column == "checksum")
+            })
+            .collect::<Vec<_>>();
         if actual.len() != required.len()
             || required
                 .iter()
@@ -337,6 +346,9 @@ pub(super) async fn validate_schema_fingerprint(
         if !relation_exists(connection, table).await? {
             continue;
         }
+        if current_version == 1 && *table == "__crank_ext_migrations" && *column == "checksum" {
+            continue;
+        }
         let row = query(
             "select data_type, is_nullable from information_schema.columns
              where table_schema = current_schema() and table_name = $1 and column_name = $2",
@@ -424,23 +436,25 @@ pub(super) async fn validate_schema_fingerprint(
             return Err(schema_error(current_version));
         }
     }
-    let required_indexes = [
-        "mcp_transport_sessions_workspace_agent_idx",
-        "mcp_transport_sessions_expires_at_idx",
-    ];
-    for index in required_indexes {
-        let present = query(
-            "select exists (select 1 from pg_catalog.pg_indexes
-             where schemaname = current_schema() and indexname = $1) as present",
-        )
-        .bind(index)
-        .fetch_one(&mut *connection)
-        .await
-        .map_err(|_| MigrationError::storage("preflight.schema"))?
-        .try_get::<bool, _>("present")
-        .map_err(|_| MigrationError::storage("preflight.schema"))?;
-        if !present {
-            return Err(schema_error(current_version));
+    if relation_exists(connection, "mcp_transport_sessions").await? {
+        let required_indexes = [
+            "mcp_transport_sessions_workspace_agent_idx",
+            "mcp_transport_sessions_expires_at_idx",
+        ];
+        for index in required_indexes {
+            let present = query(
+                "select exists (select 1 from pg_catalog.pg_indexes
+                 where schemaname = current_schema() and indexname = $1) as present",
+            )
+            .bind(index)
+            .fetch_one(&mut *connection)
+            .await
+            .map_err(|_| MigrationError::storage("preflight.schema"))?
+            .try_get::<bool, _>("present")
+            .map_err(|_| MigrationError::storage("preflight.schema"))?;
+            if !present {
+                return Err(schema_error(current_version));
+            }
         }
     }
     if current_version >= 3 {

crates/crank-registry/src/migrations/schema_guard_legacy_v1.rs

@@ -0,0 +1,198 @@
+use sha2::{Digest, Sha256};
+use sqlx::PgConnection;
+
+use super::authority::MigrationError;
+
+// Exact PostgreSQL 16 catalog contract produced by the last published
+// pre-ledger Community schema (commit 8318e4b).
+const LEDGERLESS_BASELINE_FINGERPRINT_SHA256: &str =
+    "0dbd7357a80c0d772de03ea2833013932697187b32fbd7b54be594e224e5f82f";
+const LEDGERLESS_MCP_FINGERPRINTS_SHA256: &[&str] = &[
+    // Initial published session table.
+    "53b58899dc388609cbd83fe8321a48878d610952a39d13b5fc8f05149b703683",
+    // Published session table after supports_elicitation was added.
+    "250e3e57f02283e9300bdff549305d49a6a875717ec4e4c332a2b9af3f883f09",
+    // Same published contract after an in-place upgrade from the initial layout.
+    "23c02db67cf83a3834b1ed7caa417eaafd7bcc69657d598ba831f06aeded4a62",
+];
+const LEDGERLESS_EXTENSION_FINGERPRINT_SHA256: &str =
+    "da06947028e3c18cc6ba93a58775722b425fd9989095f069316a146a2f45e921";
+
+const BASELINE_RELATIONS: &[&str] = &[
+    "workspaces",
+    "users",
+    "memberships",
+    "user_sessions",
+    "invitation_tokens",
+    "platform_api_keys",
+    "operations",
+    "operation_versions",
+    "published_operations",
+    "operation_samples",
+    "descriptors",
+    "agents",
+    "agent_versions",
+    "published_agents",
+    "agent_operation_bindings",
+    "secrets",
+    "secret_versions",
+    "auth_profiles",
+    "workspace_upstreams",
+    "yaml_import_jobs",
+    "import_jobs",
+    "approval_requests",
+    "invocation_logs",
+    "usage_rollups",
+];
+
+pub(super) async fn validate_ledgerless_baseline_fingerprint(
+    connection: &mut PgConnection,
+) -> Result<(), MigrationError> {
+    let actual = catalog_fingerprint(connection, BASELINE_RELATIONS).await?;
+    if actual == LEDGERLESS_BASELINE_FINGERPRINT_SHA256 {
+        Ok(())
+    } else {
+        Err(fingerprint_error())
+    }
+}
+
+pub(super) async fn validate_ledgerless_optional_fingerprints(
+    connection: &mut PgConnection,
+    has_mcp_sessions: bool,
+    has_extension_ledger: bool,
+) -> Result<(), MigrationError> {
+    if has_mcp_sessions {
+        let actual = catalog_fingerprint(connection, &["mcp_transport_sessions"]).await?;
+        if !LEDGERLESS_MCP_FINGERPRINTS_SHA256.contains(&actual.as_str()) {
+            return Err(fingerprint_error());
+        }
+    }
+    if has_extension_ledger {
+        let actual = catalog_fingerprint(connection, &["__crank_ext_migrations"]).await?;
+        if actual != LEDGERLESS_EXTENSION_FINGERPRINT_SHA256 {
+            return Err(fingerprint_error());
+        }
+    }
+    Ok(())
+}
+
+async fn catalog_fingerprint(
+    connection: &mut PgConnection,
+    relations: &[&str],
+) -> Result<String, MigrationError> {
+    let relations = relations
+        .iter()
+        .map(|value| (*value).to_owned())
+        .collect::<Vec<_>>();
+    let unsafe_catalog_state = sqlx::query_scalar::<_, bool>(
+        "with selected(table_name) as (select unnest($1::text[]))
+         select
+             exists (
+                 select 1 from pg_catalog.pg_class c
+                 join pg_catalog.pg_namespace n on n.oid = c.relnamespace
+                 join selected s on s.table_name = c.relname
+                 where n.nspname = current_schema()
+                   and (c.relpersistence <> 'p' or c.relrowsecurity
+                        or c.relforcerowsecurity or c.relreplident <> 'd')
+             )
+             or exists (
+                 select 1 from pg_catalog.pg_index i
+                 join pg_catalog.pg_class t on t.oid = i.indrelid
+                 join pg_catalog.pg_namespace n on n.oid = t.relnamespace
+                 join selected s on s.table_name = t.relname
+                 where n.nspname = current_schema()
+                   and (not i.indisvalid or not i.indisready or not i.indislive)
+             )
+             or exists (
+                 select 1 from pg_catalog.pg_policy p
+                 join pg_catalog.pg_class t on t.oid = p.polrelid
+                 join pg_catalog.pg_namespace n on n.oid = t.relnamespace
+                 join selected s on s.table_name = t.relname
+                 where n.nspname = current_schema()
+             )
+             or exists (
+                 select 1 from pg_catalog.pg_trigger tg
+                 join pg_catalog.pg_class t on t.oid = tg.tgrelid
+                 join pg_catalog.pg_namespace n on n.oid = t.relnamespace
+                 join selected s on s.table_name = t.relname
+                 where n.nspname = current_schema() and tg.tgenabled <> 'O'
+             )",
+    )
+    .bind(relations.clone())
+    .fetch_one(&mut *connection)
+    .await
+    .map_err(|_| MigrationError::storage("preflight.legacy_fingerprint"))?;
+    if unsafe_catalog_state {
+        return Err(fingerprint_error());
+    }
+    let fingerprint = sqlx::query_scalar::<_, String>(
+        "with baseline(table_name) as (select unnest($1::text[])), relation_rows as (
+            select jsonb_build_array('relation', c.relname, c.relkind::text) item
+            from pg_catalog.pg_class c
+            join pg_catalog.pg_namespace n on n.oid = c.relnamespace
+            join baseline b on b.table_name = c.relname
+            where n.nspname = current_schema()
+         ), column_rows as (
+            select jsonb_build_array(
+                'column', c.table_name, c.ordinal_position, c.column_name,
+                c.data_type, c.udt_name, c.is_nullable, coalesce(c.column_default, '')
+            ) item
+            from information_schema.columns c
+            join baseline b using (table_name)
+            where c.table_schema = current_schema()
+         ), constraint_rows as (
+            select jsonb_build_array(
+                'constraint', t.relname, c.conname, c.contype::text,
+                c.convalidated, pg_get_constraintdef(c.oid, true)
+            ) item
+            from pg_catalog.pg_constraint c
+            join pg_catalog.pg_class t on t.oid = c.conrelid
+            join pg_catalog.pg_namespace n on n.oid = t.relnamespace
+            join baseline b on b.table_name = t.relname
+            where n.nspname = current_schema()
+         ), index_rows as (
+            select jsonb_build_array(
+                'index', t.relname, idx.relname,
+                replace(pg_get_indexdef(i.indexrelid), format('%I.', current_schema()), '')
+            ) item
+            from pg_catalog.pg_index i
+            join pg_catalog.pg_class idx on idx.oid = i.indexrelid
+            join pg_catalog.pg_class t on t.oid = i.indrelid
+            join pg_catalog.pg_namespace n on n.oid = t.relnamespace
+            join baseline b on b.table_name = t.relname
+            where n.nspname = current_schema()
+         ), trigger_rows as (
+            select jsonb_build_array(
+                'trigger', t.relname, tg.tgname,
+                replace(pg_get_triggerdef(tg.oid, true), format('%I.', current_schema()), '')
+            ) item
+            from pg_catalog.pg_trigger tg
+            join pg_catalog.pg_class t on t.oid = tg.tgrelid
+            join pg_catalog.pg_namespace n on n.oid = t.relnamespace
+            join baseline b on b.table_name = t.relname
+            where n.nspname = current_schema() and not tg.tgisinternal
+         ), all_rows as (
+            select item from relation_rows
+            union all select item from column_rows
+            union all select item from constraint_rows
+            union all select item from index_rows
+            union all select item from trigger_rows
+         )
+         select coalesce(jsonb_agg(item order by item::text), '[]'::jsonb)::text
+         from all_rows",
+    )
+    .bind(relations)
+    .fetch_one(connection)
+    .await
+    .map_err(|_| MigrationError::storage("preflight.legacy_fingerprint"))?;
+    Ok(format!("{:x}", Sha256::digest(fingerprint.as_bytes())))
+}
+
+fn fingerprint_error() -> MigrationError {
+    MigrationError::new(
+        "partial_sequence",
+        "preflight.legacy_fingerprint",
+        Some(1),
+        "restore_known_good_backup",
+    )
+}

crates/crank-registry/tests/integration/migrations.rs

@@ -2,6 +2,7 @@ use crank_registry::{MigrationAuthority, MigrationPreflight, PostgresRegistry};
 use sqlx::Row;
 
 mod artifact_metadata;
+mod legacy_adoption;
 mod rollback;
 
 static EVENT_TRIGGER_TEST_LOCK: tokio::sync::Mutex<()> = tokio::sync::Mutex::const_new(());
@@ -153,7 +154,7 @@ async fn changed_checksum_fails_closed_without_repair() {
     );
 }
 #[tokio::test]
-async fn legacy_core_baseline_is_consolidated_without_data_loss() {
+async fn ledgerless_legacy_baseline_is_consolidated_without_data_loss() {
     let database_url = crank_test_support::postgres_schema_url("test_legacy_core").await;
     let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
     MigrationAuthority::apply(&pool).await.unwrap();
@@ -221,7 +222,8 @@ async fn legacy_core_baseline_is_consolidated_without_data_loss() {
     }
     sqlx::query(
         "drop table __crank_migrations, __crank_migration_legacy_audit,
-         __crank_mcp_migrations, mcp_transport_sessions, __crank_ext_migrations",
+         __crank_mcp_migrations, mcp_transport_sessions, __crank_ext_migrations,
+         __crank_core_migrations",
     )
     .execute(&pool)
     .await
@@ -229,7 +231,7 @@ async fn legacy_core_baseline_is_consolidated_without_data_loss() {
     assert_eq!(
         MigrationAuthority::preflight(&pool).await.unwrap(),
         MigrationPreflight::MigrationRequired {
-            current: 1,
+            current: 0,
             target: 13,
         }
     );

crates/crank-registry/tests/integration/migrations/legacy_adoption.rs

@@ -0,0 +1,190 @@
+use super::*;
+
+async fn ledgerless_v1(pool: &sqlx::PgPool) {
+    MigrationAuthority::apply(pool).await.unwrap();
+    remove_v4_schema(pool).await;
+    remove_v3_schema(pool).await;
+    sqlx::raw_sql(
+        "drop table __crank_migrations, __crank_migration_legacy_audit;
+         drop table __crank_mcp_migrations;
+         drop index mcp_transport_sessions_expires_at_idx;
+         drop table __crank_ext_migrations;
+         create table __crank_ext_migrations (
+             extension_name text not null,
+             version integer not null,
+             applied_at timestamptz not null default now(),
+             primary key (extension_name, version)
+         );
+         drop table __crank_core_migrations;",
+    )
+    .execute(pool)
+    .await
+    .unwrap();
+}
+
+#[tokio::test]
+async fn ledgerless_baseline_with_optional_index_drift_is_rejected_without_writes() {
+    let database_url = crank_test_support::postgres_schema_url("test_ledgerless_index").await;
+    let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
+    ledgerless_v1(&pool).await;
+    sqlx::raw_sql(
+        "drop index mcp_transport_sessions_workspace_agent_idx;
+         create index mcp_transport_sessions_workspace_agent_idx
+             on mcp_transport_sessions(id);",
+    )
+    .execute(&pool)
+    .await
+    .unwrap();
+
+    let error = MigrationAuthority::apply(&pool).await.unwrap_err();
+    assert_eq!(error.code(), "partial_sequence");
+    assert_eq!(error.stage(), "preflight.legacy_fingerprint");
+    let core_exists: bool = sqlx::query_scalar(
+        "select to_regclass(format('%I.%I', current_schema(), '__crank_core_migrations')) is not null",
+    )
+    .fetch_one(&pool)
+    .await
+    .unwrap();
+    assert!(!core_exists, "rejected adoption must remain read-only");
+}
+
+#[tokio::test]
+async fn ledgerless_baseline_with_disabled_integrity_triggers_is_rejected_without_writes() {
+    let database_url = crank_test_support::postgres_schema_url("test_ledgerless_triggers").await;
+    let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
+    ledgerless_v1(&pool).await;
+    sqlx::query("alter table memberships disable trigger all")
+        .execute(&pool)
+        .await
+        .unwrap();
+
+    let error = MigrationAuthority::apply(&pool).await.unwrap_err();
+    assert_eq!(error.code(), "partial_sequence");
+    assert_eq!(error.stage(), "preflight.legacy_fingerprint");
+    let core_exists: bool = sqlx::query_scalar(
+        "select to_regclass(format('%I.%I', current_schema(), '__crank_core_migrations')) is not null",
+    )
+    .fetch_one(&pool)
+    .await
+    .unwrap();
+    assert!(!core_exists, "rejected adoption must remain read-only");
+}
+
+#[tokio::test]
+async fn published_ledgerless_baseline_upgrades_without_data_loss() {
+    let database_url = crank_test_support::postgres_schema_url("test_ledgerless_baseline").await;
+    let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
+    ledgerless_v1(&pool).await;
+    sqlx::query(
+        "insert into operations
+            (id, workspace_id, name, display_name, protocol, status, created_at, updated_at)
+         values ('op_ledgerless', 'ws_default', 'ledgerless', 'Ledgerless', 'rest', 'draft', now(), now())",
+    )
+    .execute(&pool)
+    .await
+    .unwrap();
+
+    assert_eq!(
+        MigrationAuthority::preflight(&pool).await.unwrap(),
+        MigrationPreflight::MigrationRequired {
+            current: 0,
+            target: 13,
+        }
+    );
+    MigrationAuthority::apply(&pool).await.unwrap();
+
+    let operation_count: i64 =
+        sqlx::query_scalar("select count(*) from operations where id = 'op_ledgerless'")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+    assert_eq!(operation_count, 1);
+    assert_eq!(
+        MigrationAuthority::preflight(&pool).await.unwrap(),
+        MigrationPreflight::Current { version: 13 }
+    );
+}
+
+#[tokio::test]
+async fn published_in_place_mcp_upgrade_layout_is_accepted() {
+    let database_url = crank_test_support::postgres_schema_url("test_ledgerless_mcp_upgrade").await;
+    let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
+    ledgerless_v1(&pool).await;
+    sqlx::raw_sql(
+        "drop table mcp_transport_sessions;
+         create table mcp_transport_sessions (
+             id text primary key,
+             protocol_version text not null,
+             initialized boolean not null default false,
+             workspace_slug text not null,
+             agent_slug text not null,
+             created_at timestamptz not null,
+             updated_at timestamptz not null,
+             expires_at timestamptz null
+         );
+         create index mcp_transport_sessions_workspace_agent_idx
+             on mcp_transport_sessions(workspace_slug, agent_slug, updated_at desc);
+         alter table mcp_transport_sessions
+             add column supports_elicitation boolean not null default false;",
+    )
+    .execute(&pool)
+    .await
+    .unwrap();
+
+    assert_eq!(
+        MigrationAuthority::preflight(&pool).await.unwrap(),
+        MigrationPreflight::MigrationRequired {
+            current: 0,
+            target: 13,
+        }
+    );
+    MigrationAuthority::apply(&pool).await.unwrap();
+    assert_eq!(
+        MigrationAuthority::preflight(&pool).await.unwrap(),
+        MigrationPreflight::Current { version: 13 }
+    );
+}
+
+#[tokio::test]
+async fn ledgerless_baseline_with_future_drift_is_rejected_without_writes() {
+    let database_url = crank_test_support::postgres_schema_url("test_ledgerless_drift").await;
+    let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
+    ledgerless_v1(&pool).await;
+    sqlx::query("alter table invocation_logs add column trace_id text")
+        .execute(&pool)
+        .await
+        .unwrap();
+
+    let error = MigrationAuthority::apply(&pool).await.unwrap_err();
+    assert_eq!(error.code(), "partial_sequence");
+    assert_eq!(error.stage(), "preflight.legacy_fingerprint");
+    let core_exists: bool = sqlx::query_scalar(
+        "select to_regclass(format('%I.%I', current_schema(), '__crank_core_migrations')) is not null",
+    )
+    .fetch_one(&pool)
+    .await
+    .unwrap();
+    assert!(!core_exists, "rejected adoption must remain read-only");
+}
+
+#[tokio::test]
+async fn ledgerless_baseline_with_constraint_drift_is_rejected_without_writes() {
+    let database_url = crank_test_support::postgres_schema_url("test_ledgerless_constraint").await;
+    let pool = sqlx::PgPool::connect(&database_url).await.unwrap();
+    ledgerless_v1(&pool).await;
+    sqlx::query("alter table workspaces alter column status drop not null")
+        .execute(&pool)
+        .await
+        .unwrap();
+
+    let error = MigrationAuthority::apply(&pool).await.unwrap_err();
+    assert_eq!(error.code(), "partial_sequence");
+    assert_eq!(error.stage(), "preflight.legacy_fingerprint");
+    let core_exists: bool = sqlx::query_scalar(
+        "select to_regclass(format('%I.%I', current_schema(), '__crank_core_migrations')) is not null",
+    )
+    .fetch_one(&pool)
+    .await
+    .unwrap();
+    assert!(!core_exists, "rejected adoption must remain read-only");
+}