The thread_safe gem is being deprecated and all its code has been merged
into the concurrent-ruby gem. The new class, Concurrent::Map, is exactly
the same as its predecessor except for fixes to two bugs discovered
during the merge.

`intance` should be `instance`

`hfvalue` parts should always be percent encoded, so lets do that!

Revert "use path escaping for email addresses"

This reverts commit 21ffef38.

Due to e25fdad2, we are correctly using
path escaping for email addresses.  This commit fixes the tests to
expect path escaping.

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

`render` is the only possible source for the `plain` option.  Pulling
the conditional up to the `render` method removes far away conditionals

We don't need to pass the full hash just to pull one value out.  It's
better to just pass the value that the method needs to know about so
that we can abstract it away from "options"

Before we were changing the state of the lookup_context for the duration
of the with_layout_format block, but since we already know the formats
we can just pass it explicitly.

Related with 8d7ce0f2

Prevents double submission by making disable_with the default.

Default disable_with option will only be applied if user has not
specified her/his own disable_with option, whether that is in the
`data-disable-with` string form or the
`:data => { :disable_with => "Saving..." }` hash form. disable_with
will default to the value attribute.

A configuration option was added to opt out of this functionality if
the user so desires.
`config.action_view.automatically_disable_submit_tag = false`

Sometimes you need a specific break sequence while using word wrap and as today the only option we have is "\n" and is hardcoded.

With this change you will be able to specify any break sequence ("\r\n" for example) as an option.

adding proper documentation for break_sequence in ActionView::Helpers::TextHelper.word_wrap

adding some more documentation for word_wrap custom break sequence and making sure we use new hash syntax

If, doing a test like this:

```
class BugTest < ActionView::TestCase
  def test_foo
    omg
  end
```

Will raise with:
```
RuntimeError: In order to use #url_for, you must include routing helpers
explicitly. For instance, `include
Rails.application.routes.url_helpers`.
```

Thats a bit confusing, as we are not calling url_for at all.

Browsers have not been limited to two connections per host for quite
some time now. With more connections allowed, the trade-off involved in
asset host distribution isn't so clear and it becomes more important
that developers measure actual performance before and after.

In the `tag_options` method, strings are continuously added to the
`output` string. Previously, we concatenated two strings and added the
generated string to `output`. By adding each of the strings to
`output`, one after the other, we will save the allocation of that
concatenated string.

Benchmark:

    require 'benchmark/ips'

    sep = " ".freeze

    Benchmark.ips do |x|
      x.report("string +") {
        output = ""
        output << sep + "foo"
      }
      x.report("string <<") {
        output = ""
        output << sep
        output << "foo"
      }
      x.compare!
    end

Results (Ruby 2.2.2):

    Calculating -------------------------------------
                string +    88.086k i/100ms
               string <<    94.287k i/100ms
    -------------------------------------------------
                string +      2.407M (± 5.8%) i/s -     12.068M
               string <<      2.591M (± 7.0%) i/s -     12.917M

    Comparison:
               string <<:  2591482.4 i/s
                string +:  2406883.7 i/s - 1.08x slower

In the `tag_options` method an array is used to build up elements, then `Array#*` (which is an alias for `Array#join` is called to turn the array into a string. Instead of allocating an array to build a string, we can build the string we want from the beginning.

Saved: 121,743 bytes 893 objects

content_tag's first argument is will generate a string with an html tag so `:a` will generate: `<a></a>`. When this happens, the symbol is implicitly `to_s`-d so a new string is allocated. We can get around that by using a frozen string instead which

This change buys us 74,236 bytes of memory and 1,855 fewer objects per request.

The instrument method creates new strings, the most common action to instrument is "!render_template` so we can detect when that action is occurring and use a frozen string instead.

This change buys us 113,714 bytes of memory and 1,790 fewer objects per request.

No idea why on earth this hash key isn't already optimized by MRI, but it isn't. 💩

This change buys us 74,077 bytes of memory and 1,852 fewer objects per request.

When an unknonwn key is passed to the hash in `PRE_CONTENT_STRINGS` it returns nil, when you call "#{nil}" it allocates a new empty string. We can get around this allocation by using a default value `Hash.new { "".freeze }`. We can avoid the `to_sym` call by pre-populating the hash with a symbol key in addition to a string key.

We can freeze some strings when using Array#* to reduce allocations.

Array#join can take frozen strings.

This change buys us 86,600 bytes of memory and 1,857 fewer objects per request.

I wrote a utility that helps find areas where you could optimize your program using a frozen string instead of a string literal, it's called [let_it_go](https://github.com/schneems/let_it_go). After going through the output and adding `.freeze` I was able to eliminate the creation of 1,114 string objects on EVERY request to [codetriage](codetriage.com). How does this impact execution?

To look at memory:

```ruby
require 'get_process_mem'

mem = GetProcessMem.new
GC.start
GC.disable
1_114.times { " " }
before = mem.mb

after = mem.mb
GC.enable
puts "Diff: #{after - before} mb"

```

Creating 1,114 string objects results in `Diff: 0.03125 mb` of RAM allocated on every request. Or 1mb every 32 requests.

To look at raw speed:

```ruby
require 'benchmark/ips'

number_of_objects_reduced = 1_114

Benchmark.ips do |x|
  x.report("freeze")    { number_of_objects_reduced.times { " ".freeze } }
  x.report("no-freeze") { number_of_objects_reduced.times { " " } }
end
```

We get the results

```
Calculating -------------------------------------
              freeze     1.428k i/100ms
           no-freeze   609.000  i/100ms
-------------------------------------------------
              freeze     14.363k (± 8.5%) i/s -     71.400k
           no-freeze      6.084k (± 8.1%) i/s -     30.450k
```

Now we can do some maths:

```ruby
ips = 6_226k # iterations / 1 second
call_time_before = 1.0 / ips # seconds per iteration 

ips = 15_254 # iterations / 1 second
call_time_after = 1.0 / ips # seconds per iteration 

diff = call_time_before - call_time_after

number_of_objects_reduced * diff * 100

# => 0.4530373333993266 miliseconds saved per request
```

So we're shaving off 1 second of execution time for every 220 requests. 

Is this going to be an insane speed boost to any Rails app: nope. Should we merge it: yep. 

p.s. If you know of a method call that doesn't modify a string input such as [String#gsub](https://github.com/schneems/let_it_go/blob/b0e2da69f0cca87ab581022baa43291cdf48638c/lib/let_it_go/core_ext/string.rb#L37) please [give me a pull request to the appropriate file](https://github.com/schneems/let_it_go/blob/b0e2da69f0cca87ab581022baa43291cdf48638c/lib/let_it_go/core_ext/string.rb#L37), or open an issue in LetItGo so we can track and freeze more strings. 

Keep those strings Frozen

![](https://www.dropbox.com/s/z4dj9fdsv213r4v/let-it-go.gif?dl=1)

Avoid computing the same fragment digest many times when looping over templates.

The cache is cleared on every request so template changes are still picked up.

This will silence deprecation warnings.

Most of the test can be changed from `render :text` to render `:plain`
or `render :body` right away. However, there are some tests that needed
to be fixed by hand as they actually assert the default Content-Type
returned from `render :body`.

Various grammar corrections and wrap to 80 characters.

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.

ActionController::TestResponse was removed in d9fe10cb and caused a test
failure on Action View as its test case still refers to it.