ruff/crates/ruff_macros/src/violation_metadata.rs

67 lines
1.8 KiB
Rust

use proc_macro2::TokenStream;
use quote::quote;
use syn::{Attribute, DeriveInput, Error, Lit, LitStr, Meta};
pub(crate) fn violation_metadata(input: DeriveInput) -> syn::Result<TokenStream> {
let docs = get_docs(&input.attrs)?;
let name = input.ident;
Ok(quote! {
#[automatically_derived]
#[expect(deprecated)]
impl ruff_diagnostics::ViolationMetadata for #name {
fn rule_name() -> &'static str {
stringify!(#name)
}
fn explain() -> Option<&'static str> {
Some(#docs)
}
}
})
}
/// Collect all doc comment attributes into a string
fn get_docs(attrs: &[Attribute]) -> syn::Result<String> {
let mut explanation = String::new();
for attr in attrs {
if attr.path().is_ident("doc") {
if let Some(lit) = parse_attr(["doc"], attr) {
let value = lit.value();
// `/// ` adds
let line = value.strip_prefix(' ').unwrap_or(&value);
explanation.push_str(line);
explanation.push('\n');
} else {
return Err(Error::new_spanned(attr, "unimplemented doc comment style"));
}
}
}
Ok(explanation)
}
fn parse_attr<'a, const LEN: usize>(
path: [&'static str; LEN],
attr: &'a Attribute,
) -> Option<&'a LitStr> {
if let Meta::NameValue(name_value) = &attr.meta {
let path_idents = name_value
.path
.segments
.iter()
.map(|segment| &segment.ident);
if itertools::equal(path_idents, path) {
if let syn::Expr::Lit(syn::ExprLit {
lit: Lit::Str(lit), ..
}) = &name_value.value
{
return Some(lit);
}
}
}
None
}