[feat] gva: balance: return null if the pubkey has never transited money

rust-libs/modules/gva/gql/src/queries/account_balance.rs

@@ -24,7 +24,7 @@ impl AccountBalanceQuery {
         &self,
         ctx: &async_graphql::Context<'_>,
         #[graphql(desc = "Account script or public key")] script: String,
-    ) -> async_graphql::Result<AmountWithBase> {
+    ) -> async_graphql::Result<Option<AmountWithBase>> {
         let account_script = if let Ok(pubkey) = PublicKey::from_base58(&script) {
             WalletScriptV10::single_sig(pubkey)
         } else {
@@ -34,17 +34,14 @@ impl AccountBalanceQuery {
         let data = ctx.data::<GvaSchemaData>()?;
         let dbs_reader = data.dbs_reader();
 
-        let balance = data
+        Ok(data
             .dbs_pool
             .execute(move |_| dbs_reader.get_account_balance(&account_script))
             .await??
-            .unwrap_or_default()
-            .0;
-
-        Ok(AmountWithBase {
-            amount: balance.amount() as i32,
-            base: balance.base() as i32,
-        })
+            .map(|balance| AmountWithBase {
+                amount: balance.0.amount() as i32,
+                base: balance.0.base() as i32,
+            }))
     }
 }
 

rust-libs/modules/gva/indexer/src/tx.rs

@@ -281,14 +281,10 @@ fn decrease_account_balance<B: Backend>(
         balances.get(WalletConditionsV2::from_ref(&account_script))?
     {
         let new_balance = balance - decrease_amount;
-        if new_balance > SourceAmount::ZERO {
         balances.upsert(
             WalletConditionsV2(account_script),
             SourceAmountValV2(new_balance),
         );
-        } else {
-            balances.remove(WalletConditionsV2(account_script));
-        }
     }
     Ok(())
 }
@@ -454,7 +450,7 @@ mod tests {
             gva_db
                 .balances()
                 .get(WalletConditionsV2::from_ref(&script2))?,
-            None
+            Some(SourceAmountValV2(SourceAmount::ZERO))
         );
         assert_eq!(
             gva_db
@@ -494,7 +490,7 @@ mod tests {
             gva_db
                 .balances()
                 .get(WalletConditionsV2::from_ref(&script2))?,
-            None
+            Some(SourceAmountValV2(SourceAmount::ZERO))
         );
         assert_eq!(
             gva_db