fix: user email is set to a unique index (#7917)

packages/modules/user/src/migrations/.snapshot-medusa-user.json

@@ -126,7 +126,7 @@
           "composite": false,
           "primary": false,
           "unique": false,
-          "expression": "CREATE INDEX IF NOT EXISTS \"IDX_invite_token\" ON \"invite\" (deleted_at) WHERE deleted_at IS NOT NULL"
+          "expression": "CREATE INDEX IF NOT EXISTS \"IDX_invite_deleted_at\" ON \"invite\" (deleted_at) WHERE deleted_at IS NOT NULL"
         },
         {
           "keyName": "invite_pkey",
@@ -241,7 +241,7 @@
           "composite": false,
           "primary": false,
           "unique": false,
-          "expression": "CREATE INDEX IF NOT EXISTS \"IDX_user_email\" ON \"user\" (email) WHERE deleted_at IS NULL"
+          "expression": "CREATE UNIQUE INDEX IF NOT EXISTS \"IDX_user_email\" ON \"user\" (email) WHERE deleted_at IS NULL"
         },
         {
           "keyName": "IDX_user_deleted_at",

packages/modules/user/src/migrations/Migration20240703095850.ts

@@ -0,0 +1,21 @@
+import { Migration } from "@mikro-orm/migrations"
+
+export class Migration20240703095850 extends Migration {
+  async up(): Promise<void> {
+    this.addSql('drop index if exists "IDX_user_email";')
+
+    this.addSql(
+      'CREATE UNIQUE INDEX "IDX_user_email" ON "user" (email) WHERE deleted_at IS NULL;'
+    )
+    // Adding this log here as the point of failure is not in this function, but bundled up when running all pending migration
+    console.warn(
+      `Note: If the index "IDX_user_email" fails to create, then delete any existing users with duplicate emails before retrying the migration.`
+    )
+  }
+
+  async down(): Promise<void> {
+    this.addSql(
+      'CREATE INDEX IF NOT EXISTS "IDX_user_email" ON "user" (email) WHERE deleted_at IS NULL;'
+    )
+  }
+}