me: temporarily refuse to handle mysql multi-schema schemas

Until it is implemented.

closes prisma/prisma#16274

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

@@ -124,6 +124,11 @@ pub(crate) trait SqlFlavour:
         None
     }
 
+    /// Check a schema for preview features not implemented in migrate/introspection.
+    fn check_schema_features(&self, _schema: &psl::ValidatedSchema) -> ConnectorResult<()> {
+        Ok(())
+    }
+
     /// The connection string received in set_params().
     fn connection_string(&self) -> Option<&str>;
 

migration-engine/connectors/sql-migration-connector/src/flavour/mysql.rs

@@ -139,6 +139,21 @@ impl SqlFlavour for MysqlFlavour {
         }
     }
 
+    fn check_schema_features(&self, schema: &psl::ValidatedSchema) -> ConnectorResult<()> {
+        let has_namespaces = schema
+            .configuration
+            .datasources
+            .first()
+            .map(|ds| !ds.namespaces.is_empty());
+        if let Some(true) = has_namespaces {
+            Err(ConnectorError::from_msg(
+                "multiSchema migrations and introspection are not implemented on MySQL yet".to_owned(),
+            ))
+        } else {
+            Ok(())
+        }
+    }
+
     fn connection_string(&self) -> Option<&str> {
         self.state
             .params()

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

@@ -123,6 +123,7 @@ impl SqlMigrationConnector {
         match target {
             DiffTarget::Datamodel(schema) => {
                 let schema = psl::parse_schema(schema).map_err(ConnectorError::new_schema_parser_error)?;
+                self.flavour.check_schema_features(&schema)?;
                 Ok(sql_schema_calculator::calculate_sql_schema(
                     &schema,
                     self.flavour.as_ref(),

migration-engine/migration-engine-tests/tests/schema_push/mod.rs

@@ -454,3 +454,36 @@ fn issue_repro_extended_indexes(api: TestApi) {
     api.schema_push_w_datasource(dm).send().assert_executable();
     api.schema_push_w_datasource(dm).send().assert_green().assert_no_steps();
 }
+
+#[test]
+fn multi_schema_not_implemented_on_mysql() {
+    test_setup::only!(Mysql);
+
+    let schema = r#"
+generator client {
+    provider = "prisma-client-js"
+    previewFeatures = ["multiSchema"]
+}
+
+datasource db {
+    provider = "mysql"
+    url = env("TEST_DATABASE_URL")
+    schemas = ["s1", "s2"]
+}
+
+model m1 {
+  id Int @id
+  @@schema("s2")
+}
+    "#;
+
+    let api = migration_core::migration_api(Some(schema.to_owned()), None).unwrap();
+    let err = tok(api.schema_push(migration_core::json_rpc::types::SchemaPushInput {
+        force: false,
+        schema: schema.to_owned(),
+    }))
+    .unwrap_err();
+
+    let expected = expect_test::expect![[""]];
+    expected.assert_eq(&err.to_string());
+}