feat: enforce DECIMAL(p,s) overflow in parameters

src/Ydb.Sdk/src/Ado/YdbParameter.cs

@@ -2,6 +2,8 @@
 using System.Data;
 using System.Data.Common;
 using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Numerics;
 using Ydb.Sdk.Ado.YdbType;
 using Ydb.Sdk.Value;
 
@@ -270,10 +272,55 @@ internal TypedValue TypedValue
             $"Writing value of '{value.GetType()}' is not supported without explicit mapping to the YdbDbType")
     };
 
-    private TypedValue Decimal(decimal value) =>
-        Precision == 0 && Scale == 0
-            ? value.Decimal(22, 9)
-            : value.Decimal(Precision, Scale);
+    private TypedValue Decimal(decimal value)
+    {
+        var p = (Precision == 0 && Scale == 0) ? 22 : Precision;
+        var s = (Precision == 0 && Scale == 0) ? 9  : Scale;
+
+        EnsureDecimalFits(value, p, s);
+
+        return value.Decimal((byte)p, (byte)s);
+    }
+
+    private static void EnsureDecimalFits(decimal value, int precision, int scale)
+    {
+        if (precision <= 0 || scale < 0 || scale > precision)
+            throw new ArgumentOutOfRangeException(
+                $"Invalid DECIMAL({precision},{scale}) — must have precision>0 and 0<=scale<=precision.");
+
+        GetTrimmedMantissaAndScale(value, out BigInteger mantissa, out int fracDigits /* = scale' */);
+
+        var totalDigits = mantissa.IsZero ? 1 : mantissa.ToString(CultureInfo.InvariantCulture).Length;
+
+        var intDigits = Math.Max(1, totalDigits - fracDigits);
+
+        if (fracDigits > scale)
+            throw new OverflowException(
+                $"Decimal scale overflow: fractional digits {fracDigits} exceed allowed {scale} for DECIMAL({precision},{scale}). Value={value}");
+
+        if (intDigits > (precision - scale))
+            throw new OverflowException(
+                $"Decimal precision overflow: integer digits {intDigits} exceed allowed {precision - scale} for DECIMAL({precision},{scale}). Value={value}");
+    }
+
+    private static void GetTrimmedMantissaAndScale(decimal value, out BigInteger mantissa, out int scale)
+    {
+        var bits = decimal.GetBits(value);
+        scale = (bits[3] >> 16) & 0xFF;
+
+        var lo = (uint)bits[0];
+        var mid = (uint)bits[1];
+        var hi = (uint)bits[2];
+
+        mantissa = ((BigInteger)hi << 64) | ((BigInteger)mid << 32) | lo;
+        mantissa = BigInteger.Abs(mantissa);
+
+        while (scale > 0 && !mantissa.IsZero && mantissa % 10 == 0)
+        {
+            mantissa /= 10;
+            scale--;
+        }
+    }
 
     private TypedValue NullTypedValue()
     {

src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/YdbParameterTests.cs

@@ -187,7 +187,7 @@ public async Task Date_WhenSetDateOnly_ReturnDateTime()
     [Theory]
     [InlineData("12345", "12345.0000000000", 22, 9)]
     [InlineData("54321", "54321", 5, 0)]
-    [InlineData("493235.4", "493235.40", 7, 2)]
+    [InlineData("493235.4", "493235.40", 8, 2)]
     [InlineData("123.46", "123.46", 5, 2)]
     [InlineData("-184467434073.70911616", "-184467434073.7091161600", 35, 10)]
     [InlineData("-18446744074", "-18446744074", 12, 0)]
@@ -226,6 +226,38 @@ PRIMARY KEY (DecimalField)
 
         await new YdbCommand(ydbConnection) { CommandText = $"DROP TABLE {decimalTableName};" }.ExecuteNonQueryAsync();
     }
+
+    [Fact]
+    public async Task Decimal_WhenFractionalDigitsExceedScale_Throws()
+    {
+        await using var ydb = await CreateOpenConnectionAsync();
+        var t = $"T_{Random.Shared.Next()}";
+        await new YdbCommand(ydb){ CommandText = $"CREATE TABLE {t}(d Decimal(5,2), PRIMARY KEY(d))" }.ExecuteNonQueryAsync();
+
+        var cmd = new YdbCommand(ydb)
+        {
+            CommandText = $"INSERT INTO {t}(d) VALUES (@d);",
+            Parameters = { new YdbParameter("d", DbType.Decimal, 123.456m){ Precision = 5, Scale = 2 } }
+        };
+
+        await Assert.ThrowsAsync<OverflowException>(() => cmd.ExecuteNonQueryAsync());
+    }
+
+    [Fact]
+    public async Task Decimal_WhenIntegerDigitsExceedPrecisionMinusScale_Throws()
+    {
+        await using var ydb = await CreateOpenConnectionAsync();
+        var t = $"T_{Random.Shared.Next()}";
+        await new YdbCommand(ydb){ CommandText = $"CREATE TABLE {t}(d Decimal(5,0), PRIMARY KEY(d))" }.ExecuteNonQueryAsync();
+
+        var cmd = new YdbCommand(ydb)
+        {
+            CommandText = $"INSERT INTO {t}(d) VALUES (@d);",
+            Parameters = { new YdbParameter("d", DbType.Decimal, 100000m){ Precision = 5, Scale = 0 } } // 6 целых цифр
+        };
+
+        await Assert.ThrowsAsync<OverflowException>(() => cmd.ExecuteNonQueryAsync());
+    }
 
     [Fact]
     public async Task YdbParameter_WhenYdbDbTypeSetAndValueIsNull_ReturnsNullValue()