@params are reset to pre-filter state if there are parameters in the filter's path pattern

[DannyBen]

Hello,

I am fairly sure this is a bug and not an intended behavior. I may be wrong though.

When amending @params from before blocks, a different behavior is observed when the before filter uses parameters in the path.

This was initially discussed in this StackOverflow question.

Reproduction steps

Create test.rb

# test.rb
require 'sinatra'
require 'sinatra/reloader'

set :bind, '0.0.0.0'
set :port, 3000

before            { logger.info "before 1" ; @params['before-1'] = 'yes' }
before('/hi')     { logger.info "before 2" ; @params['before-2'] = 'yes' }
before('/:id/hi') { logger.info "before 3" ; @params['before-3'] = 'yes' }

get('/')       { params.to_json }  # pass
get('/hi')     { params.to_json }  # pass
get('/:id/hi') { params.to_json }  # FAIL

Run it:

$ ruby test.rb

Then access it with these three calls:

$ curl localhost:3000/
$ curl localhost:3000/hi
$ curl localhost:3000/123/hi

Actual behavior

The before filters append values to the @params hash properly, except in the last case:

$ curl localhost:3000/
{"before-1":"yes"}

$ curl localhost:3000/hi
{"before-1":"yes","before-2":"yes"}

$ curl localhost:3000/123/hi
{"before-1":"yes","id":"123"}

Expected behavior

Expecting to have the third before filter work as well, and set the value for @params['before-3'].

$ curl localhost:3000/123/hi
{"before-1":"yes","id":"123", "before-3":"yes"}

Additional information

As was pointed out in Amadan's answer on StackOverflow, the two places in the code that play a part in this are:

sinatra/lib/sinatra/base.rb

Line 1022 in b008189

original, @params = @params, @params.merge(params) if params.any?

and

sinatra/lib/sinatra/base.rb

Line 1041 in b008189

@params = original if original

[jkowens]

I agree, this looks like a bug. We need to remove routing params from the @params hash without losing other key/value pairs that could have been added.

[horaciob]

Hi there I've added a test for this scenario, @jkowens PR makes test run successfully.