avoid bindgen-generated Debug impl of dtls_hello_verify_t

Author: RalfJung

tinydtls-sys/build.rs

@@ -112,6 +112,8 @@ fn main() {
         .parse_callbacks(Box::new(bindgen::CargoCallbacks))
         .default_enum_style(EnumVariation::Rust { non_exhaustive: true })
         .rustfmt_bindings(false)
+        // Some types cannot have `Debug` as they are packed and have non-Copy fields.
+        .no_debug("dtls_hello_verify_t")
         // Declarations that should be part of the bindings.
         .allowlist_function("dtls_.*")
         .allowlist_type("dtls_.*")

tinydtls-sys/src/lib.rs

@@ -12,6 +12,8 @@
 #![allow(non_upper_case_globals)]
 #![allow(deref_nullptr)]
 
+use std::fmt;
+
 use libc::{sockaddr, sockaddr_in, sockaddr_in6, sockaddr_storage, socklen_t};
 
 #[cfg(target_family = "windows")]
@@ -32,6 +34,19 @@ pub unsafe fn dtls_set_handler(ctx: *mut dtls_context_t, h: *mut dtls_handler_t)
     (*ctx).h = h;
 }
 
+// For backwards-compatibility, we add a Debug implementation of dtls_hello_verify_t.
+// (Automatic derive stopped working with https://github.com/rust-lang/rust/pull/104429.)
+impl fmt::Debug for dtls_hello_verify_t {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self { version, cookie_length, cookie } = self;
+        fmt.debug_struct("dtls_hello_verify_t")
+            .field("version", version)
+            .field("cookie_length", cookie_length)
+            .field("cookie", cookie)
+            .finish()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;