fix: route conflict when static and dynamic routes overlap

[johan456789]

Description

This report is from discord. Route conflict when static and dynamic routes overlap; static route should take precedence

Given routes:

• Static: /bar
• Dynamic: /[foo]

Dart Frog CLI (v1.2.6) reports a route conflict when you run dart_frog dev or dart_frog build:

Route conflict detected. /<foo> and /bar both resolve to /<foo>.

Steps To Reproduce

1. create a [foo].dart in /routes

   import 'package:dart_frog/dart_frog.dart';
   
   Future<Response> onRequest(RequestContext context, String foo) async {
     // Simulate catch-all for any dynamic segment; return 404 for demonstration.
     return Response.json(statusCode: 404, body: {
       'route': 'dynamic /[foo]',
       'param': foo,
       'message': 'not found (example)'
     });
   }

2. create a bar.dart in /routes

   import 'package:dart_frog/dart_frog.dart';
   
   Response onRequest(RequestContext context) {
     return Response.json(body: {'route': 'static /bar'});
   }

3. run dart_frog dev or dart_frog build

4. see the error Route conflict detected. /<foo> and /bar both resolve to /<foo>.

Expected Behavior

There should be no route conflict. Static routes should take precedence over dynamic routes (similar to frameworks like Next.js). The dynamic route can act as a catch-all for all other values.

Next.js' doc:

Additional Context

If the dynamic part is not at the end, the error is reported differently.

e.g. /bar/baz and /<foo>/baz:

Route conflict detected. /bar/baz and /<foo>/baz both resolve to /bar/baz.
Route conflict detected. /<foo>/baz and /bar/baz both resolve to /<foo>/baz.

[paurakhsharma]

There is already an issue for this: #631