in mysql from 8.0.13, the BLOB, TEXT, GEOMETRY, and JSON data types can be…

in mysql from 8.0.13, the BLOB, TEXT, GEOMETRY, and JSON data types can be assigned a default value only if the value is written as an expression, even if the expression value is a literal

src/Migrations/Version20210120161945.php

@@ -20,7 +20,7 @@ final class Version20210120161945 extends AbstractMigration
     public function up(Schema $schema): void
     {
         // this up() migration is auto-generated, please modify it to your needs
-        $this->addSql("ALTER TABLE flux CHANGE hash hash LONGTEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT 'tmp'");
+        $this->addSql("ALTER TABLE flux CHANGE hash hash LONGTEXT CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT ('tmp')");
     }
 
     public function down(Schema $schema): void