fix: ignore non-canonical asset names when scaling

internal/funds/scaling.go

@@ -52,14 +52,19 @@ func BuildScaledAsset(baseAsset string, scale int64) string {
 // GetAssets collects, per scale, the (uncolored) amount an account holds of
 // baseAsset. Scaling converts only uncolored balances and emits uncolored
 // postings, so colored balances are excluded.
+//
+// Postings name the asset with BuildScaledAsset, so a balance whose asset is not
+// in that form (e.g. "EUR/0", "EUR/02") is excluded too: it can't be withdrawn
+// under the name the conversion would post, and it would collide with the
+// canonical asset of the same scale.
 func GetAssets(accountBalances []AccountBalance, baseAsset string) map[int64]*big.Int {
 	result := make(map[int64]*big.Int)
 	for _, accBalance := range accountBalances {
 		if accBalance.Color != "" {
 			continue
 		}
 		accBalanceAsset, scale := GetBaseAndScale(accBalance.Asset)
-		if accBalanceAsset == baseAsset {
+		if accBalanceAsset == baseAsset && BuildScaledAsset(baseAsset, scale) == accBalance.Asset {
 			result[scale] = new(big.Int).Set(accBalance.Amount)
 		}
 	}

internal/funds/scaling_test.go

@@ -24,6 +24,21 @@ func TestGetAssetsExcludesColoredBalances(t *testing.T) {
 	}, assets)
 }
 
+func TestGetAssetsExcludesNonCanonicalAssets(t *testing.T) {
+	assets := funds.GetAssets([]funds.AccountBalance{
+		{Asset: "EUR", Amount: big.NewInt(5)},
+		{Asset: "EUR/0", Amount: big.NewInt(0)},
+		{Asset: "EUR/02", Amount: big.NewInt(3)},
+		{Asset: "EUR/x", Amount: big.NewInt(4)},
+		{Asset: "EUR/2", Amount: big.NewInt(100)},
+	}, "EUR")
+
+	require.Equal(t, map[int64]*big.Int{
+		0: big.NewInt(5),
+		2: big.NewInt(100),
+	}, assets)
+}
+
 func TestScalingAvoidSwappingAlreadyHaveAsset(t *testing.T) {
 	// Need [USD/2 200]
 	// Got: {USD/2 100, USD 2}

internal/interpreter/testdata/script-tests/experimental/asset-scaling/scaling.num.specs.json

@@ -104,6 +104,41 @@
         }
       ]
     },
+    {
+      "it": "a non-canonical asset of the same scale does not mask the canonical one",
+      "balances": [
+        {
+          "account": "src",
+          "asset": "EUR",
+          "amount": 4
+        },
+        {
+          "account": "src",
+          "asset": "EUR/0",
+          "amount": 0
+        }
+      ],
+      "expect.postings": [
+        {
+          "source": "src",
+          "destination": "swap",
+          "asset": "EUR",
+          "amount": 4
+        },
+        {
+          "source": "swap",
+          "destination": "src",
+          "asset": "EUR/2",
+          "amount": 400
+        },
+        {
+          "source": "src",
+          "destination": "dest",
+          "asset": "EUR/2",
+          "amount": 400
+        }
+      ]
+    },
     {
       "it": "fails when there aren't enough funds",
       "balances": [