fix: do not remove from slice with iterating over it in amm engine

core/execution/amm/engine.go

@@ -258,6 +258,7 @@ func (e *Engine) OnMinCommitmentQuantumUpdate(ctx context.Context, c *num.Uint)
 
 // OnMTM is called whenever core does an MTM and is a signal that any pool's that are closing and have 0 position can be fully removed.
 func (e *Engine) OnMTM(ctx context.Context) {
+	rm := []string{}
 	for _, p := range e.poolsCpy {
 		if !p.closing() {
 			continue
@@ -271,7 +272,10 @@ func (e *Engine) OnMTM(ctx context.Context) {
 			e.log.Error("unable to release subaccount balance", logging.Error(err))
 		}
 		p.status = types.AMMPoolStatusCancelled
-		e.remove(ctx, p.party)
+		rm = append(rm, p.party)
+	}
+	for _, party := range rm {
+		e.remove(ctx, party)
 	}
 }
 
@@ -281,13 +285,16 @@ func (e *Engine) OnTick(ctx context.Context, _ time.Time) {
 	e.idgen = idgeneration.New(blockHash + crypto.HashStrToHex("amm-engine"+e.market.GetID()))
 
 	// any pools that for some reason have zero balance in their accounts will get stopped
+	rm := []string{}
 	for _, p := range e.poolsCpy {
 		if p.getBalance().IsZero() {
 			p.status = types.AMMPoolStatusStopped
-			e.remove(ctx, p.party)
-			continue
+			rm = append(rm, p.party)
 		}
 	}
+	for _, party := range rm {
+		e.remove(ctx, party)
+	}
 }
 
 // RemoveDistressed checks if any of the closed out parties are AMM's and if so the AMM is stopped and removed.
@@ -780,7 +787,8 @@ func (e *Engine) MarketClosing(ctx context.Context) error {
 			return err
 		}
 		p.status = types.AMMPoolStatusStopped
-		e.remove(ctx, p.party)
+		e.sendUpdate(ctx, p)
+		e.marketActivityTracker.RemoveAMMSubAccount(e.market.GetSettlementAsset(), e.market.GetID(), p.SubAccount)
 	}
 	return nil
 }

core/execution/amm/engine_test.go

@@ -647,15 +647,19 @@ func testMarketClosure(t *testing.T) {
 	ctx := vgcontext.WithTraceID(context.Background(), vgcrypto.RandomHash())
 	tst := getTestEngine(t)
 
-	party, subAccount := getParty(t, tst)
-	submit := getPoolSubmission(t, party, tst.marketID)
+	for i := 0; i < 10; i++ {
+		party, subAccount := getParty(t, tst)
+		submit := getPoolSubmission(t, party, tst.marketID)
 
-	expectSubaccountCreation(t, tst, party, subAccount)
-	require.NoError(t, tst.engine.SubmitAMM(ctx, submit, vgcrypto.RandomHash(), nil))
+		expectSubaccountCreation(t, tst, party, subAccount)
+		require.NoError(t, tst.engine.SubmitAMM(ctx, submit, vgcrypto.RandomHash(), nil))
+		expectSubAccountClose(t, tst, party, subAccount)
+	}
 
-	expectSubAccountClose(t, tst, party, subAccount)
 	require.NoError(t, tst.engine.MarketClosing(ctx))
-	assert.Len(t, tst.engine.poolsCpy, 0)
+	for _, p := range tst.engine.poolsCpy {
+		assert.Equal(t, types.AMMPoolStatusStopped, p.status)
+	}
 }
 
 func expectSubaccountCreation(t *testing.T, tst *tstEngine, party, subAccount string) {

core/execution/common/liquidity_provision_fees.go

@@ -190,6 +190,11 @@ func (m *MarketLiquidity) scaleScores(scores map[string]num.Decimal) map[string]
 	for _, s := range scores {
 		total = total.Add(s)
 	}
+
+	if total.IsZero() {
+		return scores
+	}
+
 	for k, v := range scores {
 		scores[k] = v.Div(total)
 	}

datanode/networkhistory/service_test.go

@@ -11,7 +11,7 @@
 // GNU Affero General Public License for more details.
 //
 // You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.d
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 package networkhistory_test