From 215252e7b55a3239a4f0b6b86aa03e9946c7ae2e Mon Sep 17 00:00:00 2001
From: "Shoyu Vanilla (Flint)" <modulo641@gmail.com>
Date: Mon, 7 Oct 2024 23:46:47 +0900
Subject: [PATCH] [FRAME] fix: Do not emit `Issued { amount: 0 }` event (#5946)

closes #5942

Couldn't find any emissions of `Event::Issued` without amount check
other than in this PR.

Currently, we have;


https://github.com/paritytech/polkadot-sdk/blob/4bda956d2c635c3926578741a19fbcc3de69cbb8/substrate/frame/balances/src/impl_currency.rs#L212-L220

and


https://github.com/paritytech/polkadot-sdk/blob/4bda956d2c635c3926578741a19fbcc3de69cbb8/substrate/frame/balances/src/impl_currency.rs#L293-L306
---
 prdoc/pr_5946.prdoc                           | 15 +++++++++++++++
 substrate/frame/balances/src/impl_fungible.rs |  4 +++-
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 prdoc/pr_5946.prdoc

diff --git a/prdoc/pr_5946.prdoc b/prdoc/pr_5946.prdoc
new file mode 100644
index 000000000000..9a858c980a19
--- /dev/null
+++ b/prdoc/pr_5946.prdoc
@@ -0,0 +1,15 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: "[FRAME] fix: Do not emit `Issued { amount: 0 }` event"
+
+doc:
+  - audience:
+    - Runtime Dev
+    - Runtime User
+    description: |
+      Filter out `Issued` events in `pallet-balances` module when its balance amount is zero.
+
+crates:
+  - name: pallet-balances
+    bump: patch
diff --git a/substrate/frame/balances/src/impl_fungible.rs b/substrate/frame/balances/src/impl_fungible.rs
index cf95a97d191f..4470c3cc9eb1 100644
--- a/substrate/frame/balances/src/impl_fungible.rs
+++ b/substrate/frame/balances/src/impl_fungible.rs
@@ -354,7 +354,9 @@ impl<T: Config<I>, I: 'static> fungible::Balanced<T::AccountId> for Pallet<T, I>
 		Self::deposit_event(Event::<T, I>::Withdraw { who: who.clone(), amount });
 	}
 	fn done_issue(amount: Self::Balance) {
-		Self::deposit_event(Event::<T, I>::Issued { amount });
+		if !amount.is_zero() {
+			Self::deposit_event(Event::<T, I>::Issued { amount });
+		}
 	}
 	fn done_rescind(amount: Self::Balance) {
 		Self::deposit_event(Event::<T, I>::Rescinded { amount });