Fix emoji index in reaction roles

src/migrations/1550409894008-FixEmojiIndexInReactionRoles.ts

@@ -0,0 +1,19 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class FixEmojiIndexInReactionRoles1550409894008 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<any> {
+    // In utf8mb4_swedish_ci, different native emojis are counted as the same char for indexes, which means we can't
+    // have multiple native emojis on a single message since the emoji field is part of the primary key
+    await queryRunner.query(`
+        ALTER TABLE \`reaction_roles\`
+	        CHANGE COLUMN \`emoji\` \`emoji\` VARCHAR(64) NOT NULL COLLATE 'utf8mb4_bin' AFTER \`message_id\`
+      `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<any> {
+    await queryRunner.query(`
+        ALTER TABLE \`reaction_roles\`
+	        CHANGE COLUMN \`emoji\` \`emoji\` VARCHAR(64) NOT NULL AFTER \`message_id\`
+      `);
+  }
+}