Accessing req.routeConfig in frameworkErrors handler throws TypeError

[sergburn]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.17.0

Plugin version

No response

Node.js version

16.x

Operating system

macOS

Operating system version (i.e. 20.04, 11.3, 10)

11.7

Description

An attempt to get a value of request.routeConfig in frameworkErrors handler throws an exception:

test/router-options.test.js 2>       return this[kRouteContext][kPublicRouteContext].config
test/router-options.test.js 2>                                                       ^
test/router-options.test.js 2> TypeError: Cannot read properties of undefined (reading 'config')

Steps to Reproduce

test('Should not throw on access to routeConfig frameworkErrors handler - FST_ERR_BAD_URL', t => {
  t.plan(6)

  const fastify = Fastify({
    frameworkErrors: function (err, req, res) {
      t.ok(typeof req.id === 'string')
      t.ok(req.raw instanceof Readable)
      t.same(req.routerPath, undefined)
      t.same(req.routeConfig, undefined)
      //         ^^^
      // test/router-options.test.js 2>       return this[kRouteContext][kPublicRouteContext].config
      // test/router-options.test.js 2>                                                       ^
      // test/router-options.test.js 2> TypeError: Cannot read properties of undefined (reading 'config')
      res.send(`${err.message} - ${err.code}`)
    }
  })

  fastify.get('/test/:id', (req, res) => {
    res.send('{ hello: \'world\' }')
  })

  fastify.inject(
    {
      method: 'GET',
      url: '/test/%world'
    },
    (err, res) => {
      t.error(err)
      t.equal(res.body, '\'/test/%world\' is not a valid url component - FST_ERR_BAD_URL')
    }
  )
})

Expected Behavior

Should return undefined as, for example, req.routerPath does

[sergburn]

If this is accepted as a valid issue, which requires a fix, I can work on a pull request.

[gurgunday]

Yeah I think the getter should return undefined instead of throwing

[ShivangRawat30]

can I work on this issue ??

[metcoder95]

Go for it 👍

[ShivangRawat30]

I looked at the code and figured that if either kRouteContext or kPublicRouteContext is undefined this will result in a TypeError at runtime, the req.routerPath is returning undefined
routerPath: {
get () {
return this[kRouteContext].config.url
}
},
If for routerPath it is returning undefined, this[kRouteContext] might be undefined as well, and that's why this[kRouteContext][kPublicRouteContext].config is throwing as TypeError,
or the problem might be in kPublicRouteContext.
I am new to contributing to open source, can you help me with this ?

[metcoder95]

If for routerPath it is returning undefined, this[kRouteContext] might be undefined as well, and that's why this[kRouteContext][kPublicRouteContext].config is throwing as TypeError,
or the problem might be in kPublicRouteContext.

It should be a matter of treating with care the returning statement.
e.g. you can use the optional chaining to return undefined if a given value is not present

console.log(this[kRouteContext]?[kPublicRouteContext]); // Will return undefined if `kRouteContext` is undefined

[ShivangRawat30]

@sergburn I am having hard time Reproducing the Error can you please tell me where you wrote the above code.

[sergburn]

@ShivangRawat30 put it to tests/router_options.test.js and add const { Readable } = require('stream') at the top

[ShivangRawat30]

@metcoder95

console.log(this[kRouteContext][kPublicRouteContext])  //is undefined but when i logged 
console.log(this[kRouteContext]) //it is logging [object, Object]

which means an object is present in this[kRouteContext] but is unable to get the value from [kPublicRouteContext]

[giuliowaitforitdavide]

I provided a fix for this bug in #4826
Sorry @ShivangRawat30 , I didn't read you were already working on that

[metcoder95]

@metcoder95

console.log(this[kRouteContext][kPublicRouteContext])  //is undefined but when i logged 
console.log(this[kRouteContext]) //it is logging [object, Object]

which means an object is present in this[kRouteContext] but is unable to get the value from [kPublicRouteContext]

That means that kRouteContext does not contains any value, for instance when trying to access config prop it will throw as we are trying to access a nonexistent value