Corrected a hash modification while iterating issue.

[Jack12816]

- What is it good for

There is a nasty bug on edge case usage of nested mounted APIs which use a shared class-helper method to abstract the creation of a route. With this fix in place, no errors are raised. Otherwise a RuntimeError: can't add a new key into hash during iteration is raised. This is caused by an inline modification of the @setup set inside the Grape::API class. This error is caused by the definition of the helper method in a specific way. The following form causes the issue:

def uniqe_id_route
  params do
    use :unique_id
  end
  route_param(:id) do
    yield
  end
end  

while this form works as expected:

def uniqe_id_route(&block)
  params do
    use :unique_id
  end
  route_param(:id, &block)
end

- What I did

I just converted the inline set modification into a reassignment of a freshly built set and added a test that proves the bugfix.

- A picture of a cute animal (not mandatory but encouraged)

[dblock]

Doesn't this start adding duplicates into @setup? It's a Set.

[Jack12816]

Doesn't this start adding duplicates into @setup? It's a Set.

No, it does not add duplicates, because it's a set. Example:

block1 = proc { false }
block2 = proc { true }

setup = Set.new
setup << { method: :default_format, args: [:json], block: block1 }
setup << { method: :default_format, args: [:text], block: block2 }
setup << { method: :default_format, args: [:text], block: block2 }
# =>
# #<Set: {{:method=>:default_format,
#   :args=>[:json],
#   :block=>#<Proc:0x000055bbcbe3a8f0 (irb):5>},
#  {:method=>:default_format,
#   :args=>[:text],
#   :block=>#<Proc:0x000055bbcb83dce0 (irb):6>}}>

setup = Set.new
setup += [{ method: :default_format, args: [:json], block: block1 }]
setup += [{ method: :default_format, args: [:text], block: block2 }]
setup += [{ method: :default_format, args: [:text], block: block2 }]
# #<Set: {{:method=>:default_format,
#   :args=>[:json],
#   :block=>#<Proc:0x000055bbcbe3a8f0 (irb):5>},
#  {:method=>:default_format,
#   :args=>[:text],
#   :block=>#<Proc:0x000055bbcb83dce0 (irb):6>}}>

[dblock]

Looks good, thank you.

[marcusg]

@dblock can you estimate when a new version can be released including this patch?

[dblock]

I can do it this week unless someone gets it before me, add your +1 to #2163