fix: fixes hideEmpty not returning routes when no filter is provided

[edge33]

Fix: hideEmpty dropping routes when no routesFilter is provided

Problem

When calling app.overview({ hideEmpty: true }) without a routesFilter, all routes were silently dropped from the output — even when routes existed on the encapsulation context.

The root cause is in the handleRoutes function in lib/utils.js. This function is called from the JSON.stringify replacer inside filterStructure. The previous code had two branches:

1. If opts.routesFilter is set, filter and return the routes (or undefined if the filtered result is empty and hideEmpty is on).
2. If opts.hideEmpty is set and value.length === 0, return undefined.

When hideEmpty: true was set but no routesFilter was provided, and the routes array was non-empty, the function fell through both branches without hitting any return statement — implicitly returning undefined. Since JSON.stringify omits keys whose replacer returns undefined, the routes property was stripped from the output entirely.

Fix

Added an explicit return of the routes array when it is non-empty and no routesFilter is provided:

if (opts.hideEmpty && value.length === 0) {
  return undefined
}
if (value.length) {
  return value
}

This ensures the handleRoutes function covers all code paths:

routesFilter	Routes exist	hideEmpty	Result before fix	Result after fix
yes	yes (after filter)	any	routes returned	routes returned
yes	no (after filter)	true	undefined	undefined
no	yes	true	undefined (bug)	routes returned
no	no	true	undefined	undefined
no	yes	false	undefined (bug)	routes returned

Example

const app = fastify({ exposeHeadRoutes: false })
await app.register(fastifyOverview)

app.get('/get', function noop () {})
app.get('/post', function noop () {})

await app.ready()
const root = app.overview({ hideEmpty: true })

// Before fix: root.routes === undefined
// After fix:
root.routes
// [
//   { method: 'GET', prefix: '', url: '/get' },
//   { method: 'GET', prefix: '', url: '/post' }
// ]

Test coverage

Added a dedicated test case ('hide empty with no routes filter') that registers routes on the root instance, calls app.overview({ hideEmpty: true }) without a routesFilter, and asserts the routes are present in the output.

[Eomm]

windows + node20 nevermind