4.2.1 introduced a change to the way `translate`/`t` works with an
option of `default: [[]]`. In 4.2.0, this would give a default value of
`[]`, but in 4.2.1, it leads to a missing translation.

`default: [[]]` is again allowed for cases where a default of `[]` is
needed.

This addresses GitHub issue 19640.

Strip nils out of default translations. Fixes #19419

The previous version of rails(4.2.0) you can pass objects
to the default option of translation helper.

For example:

```ruby
  t('foo', default: 1)
```

But on rails 4.2.1 version this kind of use stopped to work,
because started only to accept String types.

Now with this fix we can use orther value types on this
helper again.

Previously default translation keys that didn't end in `_html`, but came
after a missing key that ended in `_html` were being returned as
html_safe. Now they are not. Fixes #18257

Previously, when the `:raise` options was set to `false`, it would get overwritten to `true`, preventing custom exception handlers to be used.

not required include ActionView::Helpers::TagHelper in test as well

`options[:default]` and `options[:raise]` can be mistakenly added to the `options` hash. This can be a problem if you're reusing the same object.

Add a config to setup whether raise exception for missing translation or
not.

Before ec16ba75,
ActionView::Helpers::TranslationHelper#translate has raised errors with
specifying options[:raise] to true.

This should work by this fix:

     begin
       t(:"translations.missing", raise: true)
     rescue I18n::MissingTranslationData
       p :hello!
     end

i18n doesn't depend on active support which means it can't use our html_safe
code to do its escaping when generating the spans.  Rather than try to sanitize
the output from i18n, just revert to our old behaviour of rescuing the error
and constructing the tag ourselves.

Fixes: CVE-2013-4491

* Added tests for 'else' case in ActionView::Helpers::TranslationHelper#wrap_translate_defaults
* Also updated the testing syntax of translation.html_safe? asserts to provide better output upon failure.

https://github.com/rails/rails/issues/4027

Reason: After another round of discussion, it has been
decided to let interpolation deal with unsafe strings
as it should do.

This reverts commit d57d8098.

Signed-off-by: NAndrew White <andyw@pixeltrix.co.uk>

bump the i18n gem to 0.6.0beta1 and update docs for the i18n exception handler [#6739 state:committed]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Don't catch exceptions here. Instead only declare that we want exceptions to be rescued as :html, but also let users configure reactions to exceptions in I18n.
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Revert "translation method for arrays on TranslationHelper module returns an array where values for keys of the form (.|_)html keys are html_safe"

This reverts commit 05c95b5c.
Signed-off-by: NJosé Valim <jose.valim@gmail.com>