Why Does Magento 2 Force URLs to be 3+ Characters

Question

If you attempt to create a module with a front name like hello-world in Magento 2, you'll get an error that looks like this.

Invalid XML in file /Users/alanstorm/Sites/magento-2-with-keys/magento2/app/code/Pulsestorm/HelloPestle/etc/frontend/routes.xml:
Element 'route', attribute 'id': [facet 'pattern'] The value 
'hello-world' is not accepted by the pattern '[A-Za-z0-9_]{3,}'.

It seems like Magento doesn't want URL front names that have anything other than a number, letter, or underscore in them. It also forces front names to have three or more characters.

The number, letter, and underscore limitation make sense since a route ID is used to create a layout handle and "special" characters there may cause a problem. However, the three character limit is confusing.

Does anyone know the reason for this?

Answer 1

The reason was to avoid messy declarations with too short identifiers (same as too short variable limitations in PHP code style analyzers).

It was applied to multiple field types. Route front name has this limitation by mistake. It will be fixed

Answer 2

change hello-world as hello_world

Valid characters are alphabet, numeric and _

Answer 3

Yes, it's in .xsd (routerIdType, routeIdType, moduleNameType, beforeAfterType, routeFrontNameType). Reason is unknown.

https://github.com/magento/magento2/blob/077584c99ebb8007cad176c3b9a0144a05c259cd/lib/internal/Magento/Framework/App/etc/routes.xsd

https://github.com/magento/magento2/blob/077584c99ebb8007cad176c3b9a0144a05c259cd/lib/internal/Magento/Framework/App/etc/routes_merged.xsd