fix: ScopedIp considered Eq when interface_ids change

src/dns_parser.rs

@@ -21,7 +21,7 @@ use std::{
     collections::HashMap,
     convert::TryInto,
     fmt,
-    hash::{Hash, Hasher},
+    hash::Hash,
     net::{IpAddr, Ipv4Addr, Ipv6Addr},
     str,
     time::SystemTime,
@@ -66,31 +66,14 @@ impl From<&Interface> for InterfaceId {
 }
 
 /// An IPv4 address with interface identifiers indicating which interfaces discovered it.
-///
-/// Two `ScopedIpV4` values are considered equal if their addresses are equal,
-/// regardless of which interfaces discovered them.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
 #[cfg_attr(feature = "serde", derive(Deserialize, Serialize))]
 pub struct ScopedIpV4 {
     addr: Ipv4Addr,
     /// The interfaces this address was discovered on.
     interface_ids: Vec<InterfaceId>,
 }
 
-impl PartialEq for ScopedIpV4 {
-    fn eq(&self, other: &Self) -> bool {
-        self.addr == other.addr
-    }
-}
-
-impl Eq for ScopedIpV4 {}
-
-impl Hash for ScopedIpV4 {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        self.addr.hash(state);
-    }
-}
-
 impl ScopedIpV4 {
     /// Creates a new `ScopedIpV4` with a single interface identifier.
     pub fn new(addr: Ipv4Addr, interface_id: InterfaceId) -> Self {

src/service_daemon.rs

@@ -2561,8 +2561,15 @@ impl Zeroconf {
                     } else {
                         let scoped = dns_a.address();
                         if let ScopedIp::V4(v4) = &scoped {
-                            // Merge interface_ids if this V4 addr already exists
-                            if let Some(mut existing) = resolved_service.addresses.take(&scoped) {
+                            // Merge interface_ids if this V4 addr already exists.
+                            // Linear scan by IP since Eq/Hash include interface_ids.
+                            let existing = resolved_service
+                                .addresses
+                                .iter()
+                                .find(|a| a.to_ip_addr() == IpAddr::V4(*v4.addr()))
+                                .cloned();
+                            if let Some(mut existing) = existing {
+                                resolved_service.addresses.remove(&existing);
                                 if let ScopedIp::V4(existing_v4) = &mut existing {
                                     for id in v4.interface_ids() {
                                         existing_v4.add_interface_id(id.clone());

src/service_info.rs

@@ -1706,6 +1706,33 @@ mod tests {
         assert!(service_info.is_address_supported(&intf_loopback_v6));
     }
 
+    #[test]
+    fn test_scoped_ip_set_detects_interface_id_change() {
+        use crate::{InterfaceId, ScopedIp, ScopedIpV4};
+        use std::collections::HashSet;
+
+        let intf1 = InterfaceId {
+            name: "en0".to_string(),
+            index: 1,
+        };
+        let intf2 = InterfaceId {
+            name: "en1".to_string(),
+            index: 2,
+        };
+        let addr = Ipv4Addr::new(192, 168, 1, 100);
+
+        let scoped_v4_one_intf = ScopedIpV4::new(addr, intf1);
+        let mut scoped_v4_two_intfs = scoped_v4_one_intf.clone();
+        scoped_v4_two_intfs.add_interface_id(intf2);
+
+        assert_ne!(scoped_v4_one_intf, scoped_v4_two_intfs);
+
+        let set_old: HashSet<ScopedIp> = HashSet::from([ScopedIp::V4(scoped_v4_one_intf)]);
+        let set_new: HashSet<ScopedIp> = HashSet::from([ScopedIp::V4(scoped_v4_two_intfs)]);
+
+        assert_ne!(set_old, set_new);
+    }
+
     #[cfg(test)]
     #[cfg(feature = "serde")]
     mod serde {