chore: add support transactional ddl for client

I didn't know that mysql doesn't support transactional ddl.
It means that we cannot create table, alter table and etc. in
transaction. At the moment migra supports only postgres client,
that can be use transaction for ddl.

migra-cli/src/database/clients/mysql.rs

@@ -10,7 +10,7 @@ pub struct MySqlConnection {
 
 impl OpenDatabaseConnection for MySqlConnection {
     fn open(connection_string: &str) -> StdResult<Self> {
-        let pool = Pool::new(connection_string)?;
+        let pool = Pool::new_manual(1, 1, connection_string)?;
         let conn = pool.get_conn()?;
         Ok(MySqlConnection { conn })
     }
@@ -25,6 +25,8 @@ impl DatabaseStatements for MySqlConnection {
     }
 }
 
+impl SupportsTransactionalDDL for MySqlConnection {}
+
 impl DatabaseConnection for MySqlConnection {
     fn batch_execute(&mut self, query: &str) -> StdResult<()> {
         self.conn.query_drop(query)?;

migra-cli/src/database/clients/postgres.rs

@@ -23,6 +23,13 @@ impl DatabaseStatements for PostgresConnection {
     }
 }
 
+impl SupportsTransactionalDDL for PostgresConnection {
+    #[inline]
+    fn supports_transactional_ddl(&self) -> bool {
+        true
+    }
+}
+
 impl DatabaseConnection for PostgresConnection {
     fn batch_execute(&mut self, query: &str) -> StdResult<()> {
         self.client.batch_execute(query)?;

migra-cli/src/database/connection.rs

@@ -13,7 +13,14 @@ pub trait DatabaseStatements {
     fn create_migration_table_stmt(&self) -> &'static str;
 }
 
-pub trait DatabaseConnection: DatabaseStatements {
+pub trait SupportsTransactionalDDL {
+    #[inline]
+    fn supports_transactional_ddl(&self) -> bool {
+        false
+    }
+}
+
+pub trait DatabaseConnection: DatabaseStatements + SupportsTransactionalDDL {
     fn batch_execute(&mut self, query: &str) -> StdResult<()>;
 
     fn execute<'b>(&mut self, query: &str, params: ToSqlParams<'b>) -> StdResult<u64>;

migra-cli/src/database/mod.rs

@@ -9,6 +9,7 @@ pub mod prelude {
     pub use super::adapter::{ToSql, ToSqlParams, TryFromSql};
     pub use super::connection::{
         AnyConnection, DatabaseConnection, DatabaseStatements, OpenDatabaseConnection,
+        SupportsTransactionalDDL,
     };
     pub use super::migration::ManageMigration;
     pub use super::transaction::ManageTransaction;

migra-cli/src/database/transaction.rs

@@ -48,14 +48,14 @@ where
 }
 
 pub fn maybe_with_transaction<TrxFnMut, Res>(
-    with: bool,
+    is_needed: bool,
     conn: &mut AnyConnection,
     trx_fn: &mut TrxFnMut,
 ) -> StdResult<Res>
 where
     TrxFnMut: FnMut(&mut AnyConnection) -> StdResult<Res>,
 {
-    if with {
+    if is_needed && conn.supports_transactional_ddl() {
         with_transaction(conn, trx_fn)
     } else {
         trx_fn(conn)

migra-cli/tests/commands.rs

@@ -481,22 +481,6 @@ mod upgrade {
             Ok(())
         })?;
 
-        #[cfg(feature = "mysql")]
-        inner("mysql_invalid", || {
-            use mysql::prelude::*;
-
-            let pool = mysql::Pool::new(MYSQL_URL)?;
-            let mut conn = pool.get_conn()?;
-
-            let articles_res = conn.query_drop("SELECT a.id FROM articles AS a");
-            let persons_res = conn.query_drop("SELECT p.id FROM persons AS p");
-
-            assert!(articles_res.is_ok());
-            assert!(persons_res.is_err());
-
-            Ok(())
-        })?;
-
         Ok(())
     }
 
@@ -533,23 +517,6 @@ mod upgrade {
             Ok(())
         })?;
 
-        // TODO: Need to investigate how fix single transaction for Mysql
-        // #[cfg(feature = "mysql")]
-        // inner("mysql_invalid", || {
-        //     use mysql::prelude::*;
-
-        //     let pool = mysql::Pool::new(MYSQL_URL)?;
-        //     let mut conn = pool.get_conn()?;
-
-        //     let articles_res = conn.query_drop("SELECT a.id FROM articles AS a");
-        //     let persons_res = conn.query_drop("SELECT p.id FROM persons AS p");
-
-        //     assert!(articles_res.is_err());
-        //     assert!(persons_res.is_err());
-
-        //     Ok(())
-        // })?;
-
         Ok(())
     }
 }

migra-cli/tests/data/Migra_mysql_invalid.toml

@@ -1,4 +0,0 @@
-root = "./mysql_invalid"
-
-[database]
-connection = "mysql://mysql:mysql@localhost:6001/migra_tests"

migra-cli/tests/data/mysql_invalid/migrations/210218232851_create_articles/down.sql

@@ -1,3 +0,0 @@
--- This file should undo anything in `up.sql`
-
-DROP TABLE articles;

migra-cli/tests/data/mysql_invalid/migrations/210218232851_create_articles/up.sql

@@ -1,8 +0,0 @@
--- Your SQL goes here
-
-CREATE TABLE articles (
-    id          int         AUTO_INCREMENT PRIMARY KEY,
-    title       text        NOT NULL CHECK (length(title) > 0),
-    content     text        NOT NULL,
-    created_at  timestamp   NOT NULL DEFAULT current_timestamp
-);

migra-cli/tests/data/mysql_invalid/migrations/210218233414_create_persons/down.sql

@@ -1,6 +0,0 @@
--- This file should undo anything in `up.sql`
-
-ALTER TABLE articles
-    DROP COLUMN author_person_id;
-
-DROP TABLE persons;

migra-cli/tests/data/mysql_invalid/migrations/210218233414_create_persons/up.sql

@@ -1,12 +0,0 @@
--- Your SQL goes here
-
-CREATE TABLE persons (
-    id              int             AUTO_INCREMENT PRIMARY KEY
-    email           varchar(256)    NOT NULL UNIQUE
-    display_name    text            NOT NULL
-    created_at      timestamp       NOT NULL DEFAULT current_timestamp
-);
-
-ALTER TABLE articles
-    ADD COLUMN author_person_id int NULL
-        REFERENCES persons (id) ON UPDATE CASCADE ON DELETE CASCADE;

migra-cli/tests/data/postgres_invalid/migrations/210218233414_create_persons/up.sql

@@ -1,12 +1,14 @@
 -- Your SQL goes here
 
 CREATE TABLE persons (
-    id              SERIAL      PRIMARY KEY
+    id              SERIAL      PRIMARY KEY,
-    email           text        NOT NULL UNIQUE
+    email           text        NOT NULL UNIQUE,
-    display_name    text        NOT NULL
+    display_name    text        NOT NULL,
     created_at      timestamp   NOT NULL DEFAULT current_timestamp
 );
 
-ALTER TABLE articles
+/*          This table doesn't exist
+            ↓↓↓↓↓↓↓                     */
+ALTER TABLE recipes
     ADD COLUMN author_person_id int NULL
         REFERENCES persons (id) ON UPDATE CASCADE ON DELETE CASCADE;