manual ud: not emit event if 0 UDs claimed

pallets/universal-dividend/src/lib.rs

@@ -274,38 +274,35 @@ pub mod pallet {
             total_weight
         }
         fn do_claim_uds(who: &T::AccountId) -> DispatchResultWithPostInfo {
-            let (uds_count, uds_total) =
-                T::MembersStorage::try_mutate_exists(who, |maybe_first_eligible_ud| {
-                    if let Some(FirstEligibleUd(Some(ref mut first_ud_index))) =
-                        maybe_first_eligible_ud
-                    {
-                        let current_ud_index = CurrentUdIndex::<T>::get();
-                        if first_ud_index.get() >= current_ud_index {
-                            Ok((0, Zero::zero()))
-                        } else {
-                            let (uds_count, uds_total) = compute_claim_uds::compute_claim_uds(
-                                current_ud_index,
-                                first_ud_index.get(),
-                                PastReevals::<T>::get().into_iter(),
-                            );
-                            let _ = core::mem::replace(
-                                first_ud_index,
-                                core::num::NonZeroU16::new(current_ud_index)
-                                    .expect("unrechable because current_ud_index is never zero."),
-                            );
-                            Ok((uds_count, uds_total))
-                        }
+            T::MembersStorage::try_mutate_exists(who, |maybe_first_eligible_ud| {
+                if let Some(FirstEligibleUd(Some(ref mut first_ud_index))) = maybe_first_eligible_ud
+                {
+                    let current_ud_index = CurrentUdIndex::<T>::get();
+                    if first_ud_index.get() >= current_ud_index {
+                        DispatchResultWithPostInfo::Ok(().into())
                     } else {
-                        Err::<_, DispatchError>(Error::<T>::AccountNotAllowedToClaimUds.into())
+                        let (uds_count, uds_total) = compute_claim_uds::compute_claim_uds(
+                            current_ud_index,
+                            first_ud_index.get(),
+                            PastReevals::<T>::get().into_iter(),
+                        );
+                        let _ = core::mem::replace(
+                            first_ud_index,
+                            core::num::NonZeroU16::new(current_ud_index)
+                                .expect("unrechable because current_ud_index is never zero."),
+                        );
+                        T::Currency::deposit_creating(who, uds_total);
+                        Self::deposit_event(Event::UdsClaimed {
+                            count: uds_count,
+                            total: uds_total,
+                            who: who.clone(),
+                        });
+                        Ok(().into())
                     }
-                })?;
-            T::Currency::deposit_creating(who, uds_total);
-            Self::deposit_event(Event::UdsClaimed {
-                count: uds_count,
-                total: uds_total,
-                who: who.clone(),
-            });
-            Ok(().into())
+                } else {
+                    Err(Error::<T>::AccountNotAllowedToClaimUds.into())
+                }
+            })
         }
         fn do_transfer_ud(
             origin: OriginFor<T>,

pallets/universal-dividend/src/tests.rs

@@ -15,7 +15,7 @@
 // along with Substrate-Libre-Currency. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::mock::*;
-use frame_support::{assert_err, assert_ok};
+use frame_support::{assert_err, assert_ok, assert_storage_noop};
 
 #[test]
 fn test_claim_uds() {
@@ -35,12 +35,7 @@ fn test_claim_uds() {
 
         // Alice can claim UDs, but this should be a no-op.
         run_to_block(1);
-        assert_ok!(UniversalDividend::claim_uds(Origin::signed(1)));
-        System::assert_has_event(Event::UniversalDividend(crate::Event::UdsClaimed {
-            count: 0,
-            total: 0,
-            who: 1,
-        }));
+        assert_storage_noop!(assert_ok!(UniversalDividend::claim_uds(Origin::signed(1))));
         assert_eq!(Balances::free_balance(1), 0);
 
         // Dave is not a member, he can't claim UDs