The `url_for` methods in `actionpack` and `actionview`
now make a copy of the provided options
before generating polymorphic paths or URLs.
The bug in the previous behavior
is most noticeable in a case like:
url_options = [:new, :post, param: 'value']
if current_page?(url_options)
css_class = "active"
end
link_to "New Post", url_options, class: css_class
This is another take at #14384 as we decided to wait until `master` is
targeting Rails 5.0. This commit is implementation-complete, as it
guarantees that all the public methods on the hash-inherited Parameters
are still working (based on test case). We can decide to follow-up later
if we want to remove some methods out from Parameters.
Benchmarking the existing code:
```ruby
{ :only_path => options[:host].nil? }.merge!(options.symbolize_keys))
```
Against optimized code, that does not require a new hash or a merge:
```ruby
options = options.symbolize_keys
options[:only_path] = options[:host].nil? unless options.key?(:only_path)
options
```
We see a statistically significant performance gain:
Updated to not mutate incoming parameters
this reduces the number of comparisons and method calls `url_for`
requires. The nil case no longer calls `symbolize_keys`, we already
know options is nil, so no more ||=, and since it is nil we already know
that options[:host] will be nil too.
