I have a template with a section that should be rendered if a variable is defined. But I can't make it work. I have something like this in my project:
use serde::Serialize;
#[derive(Default,Serialize)]
struct AStruct {
parameter: Option<String>
}
// AStruct { parameter: None }
let a_struct_instance = AStruct {..Default::default()};
TEMPLATES.render("template.conf", &a_struct_instance) {...}
// template.conf example:
//
// {% if parameter is defined %}
// SOMETHING TO SHOW
// {% endif %}
The template is rendered like if parameter is defined, why is that?
The parameter field is None, but in the build-in tester function, 'value' is Some(Null) and is_some() return true on this.
https://github.com/Keats/tera/blob/master/src/builtins/testers.rs#L36
/// Returns true if `value` is defined. Otherwise, returns false.
pub fn defined(value: Option<Value>, params: Vec<Value>) -> Result<bool> {
number_args_allowed("defined", 0, params.len())?;
Ok(value.is_some())
}
What I'm doing wrong?
Well, my problem was that the testers 'is defined' or 'is undefined' checks if the variable is defined/undef, not the value of the variable.