Return user-readable drift summary in migrate dev

libs/datamodel/core/src/ast/mod.rs

@@ -52,7 +52,7 @@ pub(crate) use renderer::Renderer;
 #[derive(Debug, Clone, PartialEq)]
 pub struct SchemaAst {
     /// All models, enums, datasources, generators or type aliases
-    pub tops: Vec<Top>,
+    pub(crate) tops: Vec<Top>,
 }
 
 impl SchemaAst {

migration-engine/connectors/migration-connector/src/lib.rs

@@ -83,6 +83,9 @@ pub trait DatabaseMigrationMarker: Debug + Send + Sync {
 
     /// Is the migration empty?
     fn is_empty(&self) -> bool;
+
+    /// Render a human-readable summary of the migrations content, for drift diagnostics.
+    fn summary(&self) -> String;
 }
 
 /// Shorthand for a [Result](https://doc.rust-lang.org/std/result/enum.Result.html) where the error

migration-engine/connectors/mongodb-migration-connector/src/mongodb_migration.rs

@@ -11,6 +11,22 @@ impl DatabaseMigrationMarker for MongoDbMigration {
     fn is_empty(&self) -> bool {
         self.steps.is_empty()
     }
+
+    fn summary(&self) -> String {
+        let mut out = String::with_capacity(self.steps.len() * 10);
+
+        for step in &self.steps {
+            match step {
+                MongoDbMigrationStep::CreateCollection(collection) => {
+                    out.push_str("- Added collection `");
+                    out.push_str(collection);
+                    out.push_str("`\n");
+                }
+            }
+        }
+
+        out
+    }
 }
 
 #[derive(Debug)]

migration-engine/connectors/sql-migration-connector/src/sql_migration.rs

@@ -159,7 +159,11 @@ impl SqlMigration {
                     DriftType::RemovedTable => out.push_str("\n[-] Removed tables\n"),
                     DriftType::RemovedUdt => out.push_str("\n[-] Removed UDTs\n"),
                     DriftType::RemovedView => out.push_str("\n[-] Removed views\n"),
-                    DriftType::RedefinedTable => out.push_str("\n[*] Redefined tables\n"),
+                    DriftType::RedefinedTable => {
+                        out.push_str("\n[*] Redefined table `");
+                        out.push_str(item_name);
+                        out.push_str("`\n")
+                    }
                     DriftType::ChangedEnum => {
                         out.push_str("\n[*] Changed the `");
                         out.push_str(item_name);
@@ -373,6 +377,10 @@ impl DatabaseMigrationMarker for SqlMigration {
     fn is_empty(&self) -> bool {
         self.steps.is_empty()
     }
+
+    fn summary(&self) -> String {
+        self.drift_summary()
+    }
 }
 
 // The order of the variants matters for sorting. The steps are sorted _first_

migration-engine/core/src/commands/dev_diagnostic.rs

@@ -75,11 +75,10 @@ fn check_for_reset_conditions(output: &DiagnoseMigrationHistoryOutput) -> Option
         ))
     }
 
-    if let Some(DriftDiagnostic::DriftDetected { rollback }) = &output.drift {
-        tracing::info!(rollback = rollback.as_str(), "DriftDetected diagnostic");
-
-        reset_reasons
-            .push("Drift detected: Your database schema is not in sync with your migration history.".to_owned())
+    if let Some(DriftDiagnostic::DriftDetected { summary }) = &output.drift {
+        let mut reason = format!("Drift detected: Your database schema is not in sync with your migration history.\n");
+        reason.push_str(summary);
+        reset_reasons.push(reason);
     }
 
     match &output.history {

migration-engine/core/src/commands/diagnose_migration_history.rs

@@ -138,14 +138,12 @@ impl<'a> MigrationCommand for DiagnoseMigrationHistoryCommand {
         let (drift, error_in_unapplied_migration) = {
             if input.opt_in_to_shadow_database {
                 let drift = match connector
-                    .diff(DiffTarget::Database, DiffTarget::Migrations(&applied_migrations))
+                    .diff(DiffTarget::Migrations(&applied_migrations), DiffTarget::Database)
                     .await
                     .map(|mig| if mig.is_empty() { None } else { Some(mig) })
                 {
                     Ok(Some(rollback)) => Some(DriftDiagnostic::DriftDetected {
-                        rollback: connector
-                            .database_migration_step_applier()
-                            .render_script(&rollback, &connector.destructive_change_checker().pure_check(&rollback)),
+                        summary: rollback.summary(),
                     }),
                     Err(error) => Some(DriftDiagnostic::MigrationFailedToApply { error }),
                     _ => None,
@@ -290,8 +288,8 @@ pub enum DriftDiagnostic {
     /// The database schema of the current database does not match what would be
     /// expected at its stage in the migration history.
     DriftDetected {
-        /// A database script to correct the drift by reverting to the expected schema.
-        rollback: String,
+        /// The human-readable contents of the drift.
+        summary: String,
     },
     /// When a migration fails to apply cleanly to a shadow database.
     MigrationFailedToApply {
@@ -304,7 +302,7 @@ impl DriftDiagnostic {
     /// For tests.
     pub fn unwrap_drift_detected(self) -> String {
         match self {
-            DriftDiagnostic::DriftDetected { rollback } => rollback,
+            DriftDiagnostic::DriftDetected { summary } => summary,
             other => panic!("unwrap_drift_detected on {:?}", other),
         }
     }

migration-engine/migration-engine-tests/src/sync_test_api.rs

@@ -1,3 +1,4 @@
+pub use expect_test::expect;
 pub use test_macros::test_connector;
 pub use test_setup::{BitFlags, Capabilities, Tags};
 

migration-engine/migration-engine-tests/tests/migrations/dev_diagnostic_tests.rs

@@ -75,10 +75,8 @@ fn dev_diagnostic_detects_drift(api: TestApi) {
 
     let DevDiagnosticOutput { action } = api.dev_diagnostic(&directory).send().into_output();
 
-    assert_eq!(
-        action.as_reset(),
-        Some("Drift detected: Your database schema is not in sync with your migration history.")
-    );
+    let expected_start = "Drift detected: Your database schema is not in sync with your migration history.";
+    assert!(action.as_reset().unwrap().starts_with(expected_start));
 }
 
 #[test_connector(exclude(Postgres, Mssql))]
@@ -200,7 +198,12 @@ fn dev_diagnostic_can_detect_when_the_migrations_directory_is_behind(api: TestAp
 
     let DevDiagnosticOutput { action } = api.dev_diagnostic(&directory).send().into_output();
 
-    assert_eq!(action.as_reset(), Some(format!("- Drift detected: Your database schema is not in sync with your migration history.\n- The following migration(s) are applied to the database but missing from the local migrations directory: {}\n", name)).as_deref());
+    let message = action.as_reset().unwrap();
+    assert!(message.contains("- Drift detected: Your database schema is not in sync with your migration history"));
+    assert!(message.contains(&format!(
+        "The following migration(s) are applied to the database but missing from the local migrations directory: {}",
+        name
+    )));
 }
 
 #[test_connector]
@@ -258,13 +261,10 @@ fn dev_diagnostic_can_detect_when_history_diverges(api: TestApi) {
 
     let DevDiagnosticOutput { action } = api.dev_diagnostic(&directory).send().into_output();
 
-    let expected_message = format!(
-        "- Drift detected: Your database schema is not in sync with your migration history.\n- The migrations recorded in the database diverge from the local migrations directory. Last common migration: `{}`. Migrations applied to the database but absent from the migrations directory are: {}\n",
-        first_migration_name,
-        deleted_migration_name,
-    );
+    let message = action.as_reset().unwrap();
 
-    assert_eq!(action.as_reset(), Some(expected_message.as_str()));
+    assert!(message.contains("Drift detected: Your database schema is not in sync with your migration history"));
+    assert!(message.contains(&format!("- The migrations recorded in the database diverge from the local migrations directory. Last common migration: `{}`. Migrations applied to the database but absent from the migrations directory are: {}", first_migration_name, deleted_migration_name)));
 }
 
 #[test_connector]
@@ -462,7 +462,7 @@ fn with_an_invalid_unapplied_migration_should_report_it(api: TestApi) {
 }
 
 #[test_connector(tags(Postgres))]
-fn drift_can_be_detected_without_migrations_table(api: TestApi) {
+fn drift_can_be_detected_without_migrations_table_dev(api: TestApi) {
     let directory = api.create_migrations_directory();
 
     api.raw_cmd("CREATE TABLE \"cat\" (\nid SERIAL PRIMARY KEY\n);");
@@ -477,10 +477,14 @@ fn drift_can_be_detected_without_migrations_table(api: TestApi) {
 
     let DevDiagnosticOutput { action } = api.dev_diagnostic(&directory).send().into_output();
 
-    assert_eq!(
-        action.as_reset(),
-        Some("Drift detected: Your database schema is not in sync with your migration history.")
-    );
+    let expect = expect![[r#"
+        Drift detected: Your database schema is not in sync with your migration history.
+
+        [+] Added tables
+          - cat
+    "#]];
+
+    expect.assert_eq(action.as_reset().unwrap());
 }
 
 #[test_connector(tags(Mysql8), exclude(Vitess))]

migration-engine/migration-engine-tests/tests/migrations/diagnose_migration_history_tests.rs

@@ -89,12 +89,15 @@ fn diagnose_migration_history_with_opt_in_to_shadow_database_calculates_drift(ap
         .send_sync()
         .into_output();
 
-    let expected_rollback_warnings =
-         format!("/*\n  Warnings:\n\n  - You are about to drop the column `fluffiness` on the `{}` table. All the data in the column will be lost.\n\n*/", api.normalize_identifier("Cat"));
-
     let rollback = drift.unwrap().unwrap_drift_detected();
 
-    assert!(rollback.starts_with(&expected_rollback_warnings), "{}", rollback);
+    let snapshot = expect_test::expect![[r#"
+
+        [*] Changed the `Cat` table
+          [+] Added column `fluffiness`
+    "#]];
+
+    snapshot.assert_eq(&rollback);
 
     assert!(history.is_none());
     assert!(failed_migration_names.is_empty());
@@ -324,7 +327,7 @@ fn diagnose_migrations_history_can_detect_when_the_folder_is_behind(api: TestApi
 
     assert!(failed_migration_names.is_empty());
     assert!(edited_migration_names.is_empty());
-    assert!(matches!(drift, Some(DriftDiagnostic::DriftDetected { rollback: _ })));
+    assert!(matches!(drift, Some(DriftDiagnostic::DriftDetected { summary: _ })));
     assert_eq!(
         history,
         Some(HistoryDiagnostic::MigrationsDirectoryIsBehind {
@@ -407,7 +410,7 @@ fn diagnose_migrations_history_can_detect_when_history_diverges(api: TestApi) {
 
     assert!(failed_migration_names.is_empty());
     assert!(edited_migration_names.is_empty());
-    assert!(matches!(drift, Some(DriftDiagnostic::DriftDetected { rollback: _ })));
+    assert!(matches!(drift, Some(DriftDiagnostic::DriftDetected { summary: _ })));
     assert_eq!(
         history,
         Some(HistoryDiagnostic::HistoriesDiverge {
@@ -734,7 +737,7 @@ fn drift_can_be_detected_without_migrations_table(api: TestApi) {
         .send_sync()
         .into_output();
 
-    assert!(matches!(drift, Some(DriftDiagnostic::DriftDetected { rollback: _ })));
+    assert!(matches!(drift, Some(DriftDiagnostic::DriftDetected { summary: _ })));
     assert!(
         matches!(history, Some(HistoryDiagnostic::DatabaseIsBehind { unapplied_migration_names: migs }) if migs.len() == 1)
     );