Improvement of auto-escaping

[Amaury]

This evolution improves the auto-escaping feature.

• The escape modifier has no effect when auto-escaping is enabled (when no escape format is given, or when the html format is used), to prevent double-escaping.
• The other formats of the escape modifier (htmlall, url, urlpathinfo, quotes, javascript) are processed as we may expect, without double-escaping.
• The new force format of the escape modifier allows to force double-escaping if needed.
• The new raw modifier temporary disables auto-escaping for the expression it is used on.

This Pull Request contains the source code of this evolution, as well as its documentation and unit tests.

[wisskid]

This is looking great, @Amaury !

How do you propose we release this? Do you think this calls for a new major version, i.e. Smarty v6 or a minor (v5.4)?

One might argue this requires a major, because behavior is changing for existing templates that use |escape of some form when html auto-escaping is also enabled. On the other hand: that would very likely be unintended anyway.

[Amaury]

About the release, I would say that a minor version should be enough; I don't know if anybody if really using auto-escaping and |escape at the same time. On the other hand, it's true this is a deep change of behaviour…
I don't know, I let you choose ^^'

[Amaury]

Thank you! :)

[Amaury]

In the end, do you think you will create a major version or a minor one?

[wisskid]

I'm thinking minor.