Don't break wrangler preview when kv namespaces present

[ashleymichal]

the preview service as we use it today does not ignore kv namespace bindings, but throws an error when sent a script with those bindings. we don't want to take away a user's ability to use preview, for one, and we also want to give a helpful warning when they do.

[steveklabnik]

so, boolean parameters are generally considered to be a bad style. I actually really like what you did above, with

    let include_kv = false;

rather than just passing false and true. But we can do even better!

// note this isn't pub!
fn build_script_upload_form_with_namespaces(
    project: &Project,
    kv_namespaces: Vec<NamespaceTypeOrWhatever>,
) -> Result<Form, failure::Error> {
   // previous body of build_script_upload_form goes here
   //
   // except you don't need to set up the kv_namespaces variable
}


pub fn build_script_upload_form(
    project: &Project,
) -> Result<Form, failure::Error> {
    build_script_upload_form_with_namespaces(project, Vec::new())
}

pub fn build_script_upload_form_with_kv(
    project: &Project,
) -> Result<Form, failure::Error> {
     build_script_upload_form_with_namespaces(project, project.kv_namespaces())
}

I do not know how @ashleygwilliams feels about this kind of refactoring, but I generally prefer it. That being said, boolean parameters are not the worst, so if she prefers this code as-is, I don't think it's the end of the world.

[ashleymichal]

the boolean parameter did indeed feel Gross. I like this better, ty.

[ashleymichal]

implemented this, except called out the "weird" case which is building without kv.

[steveklabnik]

Looking good! Great call on reversing the names.