[bevy_derive] Refactor modules for better error message. (#2059)

Problem:
- When using the 'as_crate' attribute, if 'as_crate' was empty, the only
  error you would get is 'integer underflow'.

Solution:
- Provide an explicit check for the 'as_crate' attribute's token stream
  to ensure the formatting is correct.

Note:
- Also reworked 'get_meta' by not making it call 'Manifest::find' twice.
This commit is contained in:
Nathan Ward 2021-05-06 23:45:23 +00:00
parent ce6dda2d4e
commit 1690a9db97

View file

@ -46,12 +46,18 @@ fn get_meta() -> Option<Modules> {
const AS_CRATE_ATTRIBUTE_NAME: &str = "as_crate";
fn validate_as_crate_attribute(tokens: &str) -> bool {
tokens.len() > 2 && tokens.starts_with('(') && tokens.ends_with(')')
}
pub fn get_modules(attributes: &[Attribute]) -> Modules {
let mut modules = get_meta().unwrap_or_else(Modules::external);
for attribute in attributes.iter() {
if *attribute.path.get_ident().as_ref().unwrap() == AS_CRATE_ATTRIBUTE_NAME {
let value = attribute.tokens.to_string();
if value[1..value.len() - 1] == modules.bevy_render {
if !validate_as_crate_attribute(&value) {
panic!("The attribute `#[as_crate{}]` is invalid. It must follow the format `#[as_crate(<crate name>)]`", value);
} else if value[1..value.len() - 1] == modules.bevy_render {
modules.bevy_render = "crate".to_string();
}
}