fix from kql (csharp-opensource#11)

LinqToKql.Test/Provider/ProviderTests.cs

@@ -0,0 +1,45 @@
+using CSharp.OpenSource.LinqToKql.Extensions;
+using CSharp.OpenSource.LinqToKql.Provider;
+using CSharp.OpenSource.LinqToKql.Test.Model;
+
+namespace CSharp.OpenSource.LinqToKql.Test.Provider;
+
+public class ProviderTests
+{
+    [Fact]
+    public void CloneTest()
+    {
+        var q = new LinqToKqlProvider<SampleObject>("test", expression: null, providerExecutor: null);
+        var q1 = q.Where(x => x.Year == 8 && x.Description == "desc")
+                   .AsKQL()
+                   .Clone<Test1>();
+        var q2 = q1.Where(x => x.Test == "1")
+                   .AsKQL();
+        var kql = q2.TranslateToKQL();
+        var expected = string.Join(q1.Translator.PipeWithIndentation, ["test", "where Year == 8 and Description == 'desc'", "where Test == '1'"]);
+        Assert.Equal(expected, kql);
+    }
+
+    [Fact]
+    public void FromKQLTest()
+    {
+        var q = new LinqToKqlProvider<SampleObject>("test", expression: null, providerExecutor: null);
+        var q1 = q.Where(x => x.Year == 8 && x.Description == "desc")
+                  .FromKQL("| where 1 == 1", appendKQL: true)
+                  .FromKQL("where 2 == 2", appendKQL: true);
+        var q2 = q1.FromKQL("newTable", appendKQL: false);
+
+        var expected1 = string.Join(q1.Translator.PipeWithIndentation, ["test", "where Year == 8 and Description == 'desc'", "where 1 == 1", "where 2 == 2"]);
+        var expected2 = "newTable";
+        var actual1 = q1.TranslateToKQL();
+        var actual2 = q2.TranslateToKQL();
+        Assert.Equal(expected1, actual1);
+        Assert.Equal(expected2, actual2);
+    }
+}
+
+public interface Test1
+{
+    int Year { get; }
+    string Test { get; }
+}

LinqToKql/Provider/LinqToKqlProvider.cs

@@ -65,14 +65,23 @@ public virtual IQueryable<TElement> CreateQuery<TElement>(Expression expression)
         => Clone<TElement>(expression);
 
     public virtual LinqToKqlProvider<S> Clone<S>(Expression? expression = null, bool cloneExpressionOnNull = true)
-        => new LinqToKqlProvider<S>(
-                TableOrKQL,
-                expression ?? (cloneExpressionOnNull ? Expression : null),
-                ProviderExecutor,
-                Translator.Config,
-                DefaultDbName,
-                ShouldRetry
-           );
+    {
+        var kql = TableOrKQL;
+        expression ??= cloneExpressionOnNull ? Expression : null;
+        if (typeof(T) != typeof(S))
+        {
+            expression = null;
+            kql = TranslateToKQL();
+        }
+        return new(
+            kql,
+            expression,
+            ProviderExecutor,
+            Translator.Config,
+            DefaultDbName,
+            ShouldRetry
+        );
+    }
 
     public virtual async IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = default)
     {