crypto: update OtherUserIdentityData::is_device_signed to return bool

Once again: since all the callers end up calling `.is_ok()` on the result, and
the name implies it should return a bool, let's just return a bool.

crates/matrix-sdk-crypto/src/identities/device.rs

@@ -752,7 +752,7 @@ impl DeviceData {
                     // check if the other user has signed this device.
                     UserIdentityData::Other(device_identity) => {
                         own_identity.is_identity_verified(device_identity)
-                            && device_identity.is_device_signed(self).is_ok()
+                            && device_identity.is_device_signed(self)
                     }
                 }
             },
@@ -769,9 +769,7 @@ impl DeviceData {
             UserIdentityData::Own(identity) => identity.is_device_signed(self),
             // If it's a device from someone else, check
             // if the other user has signed this device.
-            UserIdentityData::Other(device_identity) => {
-                device_identity.is_device_signed(self).is_ok()
-            }
+            UserIdentityData::Other(device_identity) => device_identity.is_device_signed(self),
         }
     }
 

crates/matrix-sdk-crypto/src/identities/manager.rs

@@ -1458,7 +1458,7 @@ pub(crate) mod tests {
         let identity = manager.store.get_user_identity(other_user).await.unwrap().unwrap();
         let identity = identity.other().unwrap();
 
-        identity.is_device_signed(&device).unwrap();
+        assert!(identity.is_device_signed(&device));
     }
 
     #[async_test]
@@ -2113,7 +2113,7 @@ pub(crate) mod tests {
             .await
             .unwrap()
             .unwrap();
-        assert!(bob_identity.is_device_signed(&bob_device).is_ok());
+        assert!(bob_identity.is_device_signed(&bob_device));
         // there is also a pin violation
         assert!(bob_identity.has_pin_violation());
         // Fixing the pin violation won't fix the verification latch violation

crates/matrix-sdk-crypto/src/identities/user.rs

@@ -762,14 +762,9 @@ impl OtherUserIdentityData {
     ///
     /// * `device` - The device that should be checked for a valid signature.
     ///
-    /// Returns an empty result if the signature check succeeded, otherwise a
-    /// SignatureError indicating why the check failed.
-    pub(crate) fn is_device_signed(&self, device: &DeviceData) -> Result<(), SignatureError> {
-        if self.user_id() != device.user_id() {
-            return Err(SignatureError::UserIdMismatch);
-        }
-
-        self.self_signing_key.verify_device(device)
+    /// Returns `true` if the signature check succeeded, otherwise `false`.
+    pub(crate) fn is_device_signed(&self, device: &DeviceData) -> bool {
+        self.user_id() == device.user_id() && self.self_signing_key.verify_device(device).is_ok()
     }
 }