fix(iota-open-rpc-macros): proper handling of empty line doc comments (#5495)

* fix fn extract_doc_comments

* Update crates/iota-open-rpc-macros/src/lib.rs

* fmt

---------

Co-authored-by: Thibault Martinez <[email protected]>

Author: Alex6323

crates/iota-open-rpc-macros/src/lib.rs

@@ -336,21 +336,43 @@ fn respan_token_stream(stream: TokenStream2, span: Span) -> TokenStream2 {
         .collect()
 }
 
+/// Find doc comments by looking for #[doc = "..."] attributes.
+///
+/// Consecutive attributes are combined together. If there is a leading space,
+/// it will be removed, and if there is trailing whitespace it will also be
+/// removed. Single newlines in doc comments are replaced by spaces (soft
+/// wrapping), but double newlines (an empty line) are preserved.
 fn extract_doc_comments(attrs: &[Attribute]) -> String {
-    let s = attrs
-        .iter()
-        .filter(|attr| {
-            attr.path.is_ident("doc")
-                && match attr.parse_meta() {
-                    Ok(syn::Meta::NameValue(meta)) => matches!(&meta.lit, syn::Lit::Str(_)),
-                    _ => false,
-                }
-        })
-        .map(|attr| {
-            let s = attr.tokens.to_string();
-            s[4..s.len() - 1].to_string()
-        })
-        .join(" ");
+    let mut s = String::new();
+    let mut sep = "";
+
+    for attr in attrs {
+        if !attr.path.is_ident("doc") {
+            continue;
+        }
+
+        let Ok(syn::Meta::NameValue(meta)) = attr.parse_meta() else {
+            continue;
+        };
+
+        let syn::Lit::Str(lit) = &meta.lit else {
+            continue;
+        };
+
+        let token = lit.value();
+        let line = token.strip_prefix(" ").unwrap_or(&token).trim_end();
+
+        if line.is_empty() {
+            s.push_str("\n\n");
+            sep = "";
+        } else {
+            s.push_str(sep);
+            sep = " ";
+        }
+
+        s.push_str(line);
+    }
+
     unescape(&s).unwrap_or_else(|| panic!("Cannot unescape doc comments : [{s}]"))
 }