[Form] Document createNamed method

[javiereguiluz]

Symfony developers are used to the createForm() shortcut method provided by the base controller. Internally this shortcut uses the create() method of the FormFactory. Apparently, there is another method called createNamed() which comes in very handy when you need to simplify the generated form name (see this comment as an example).

As far as I know, this createNamed() method isn't documented.

[xabbuh]

You're right. Though I think this isn't needed really frequently. Adding a tip to the book and the components chapter should be sufficient. What do you think?

[javiereguiluz]

@xabbuh I agree that a tip in the book should be more than enough.

[stof]

A case where it is handy is when you want to generate a form with an empty root name (which is possible since 2.1), for instance when you want to use the Form component to render your login form (without having to reconfigure field names used by the security system), or when you want to create a form submitted through the query string (for filtering purposes for instance).
There is a few drawbacks to generating forms with an empty root name though (until we introduce an option to allow forms to have extra data being ignored instead of marking the form as invalid, which is not merged yet).

I also agree that a tip might be enough though

[webmozart]

Would it make sense to let forms be unnamed by default in Symfony 3.0?

[xabbuh]

@webmozart I guess naming a form is only really needed when you have to deal with more than one form in a single controller. Is that true?

[stof]

@xabbuh it is also needed in case you want to use the method override through $_POST['_method'], otherwise _method would be reported as an extra field.

[mickaelandrieu]

Hi,
Sorry to "up" this issue, but this is still an issue, will you agree to merge it if someone create a pull request for it ?

Mickaël