C#: Add response checks for batch for every command

csharp/sources/Valkey.Glide/BaseClient.cs

@@ -102,7 +102,8 @@ internal async Task<T> Command<T>(RequestType requestType, GlideString[] argumen
         BatchFfi(_clientPointer, (ulong)message.Index, ffiBatch.ToPtr(), raiseOnError, ffiOptions?.ToPtr() ?? IntPtr.Zero);
 
         // 4. Get a response and Handle it
-        return HandleServerResponse<object?[]?>(await message, true);
+        object?[]? value = HandleServerResponse<object?[]?>(await message, true);
+        return batch.ConvertResponse(value);
 
         // All memory allocated is auto-freed by `using` operator
     }
@@ -165,7 +166,7 @@ protected internal static T HandleServerResponse<R, T>(IntPtr response, bool isN
                     return null;
 #pragma warning restore CS8603 // Possible null reference return.
                 }
-                throw new Exception($"Unexpected return type from Glide: got null expected {typeof(T).GetRealTypeName()}");
+                throw new RequestException($"Unexpected return type from Glide: got null expected {typeof(T).GetRealTypeName()}");
             }
             return value is R
                 ? converter((value as R)!)

csharp/sources/Valkey.Glide/Pipeline/BaseBatch.cs

@@ -1,8 +1,11 @@
 // Copyright Valkey GLIDE Project Contributors - SPDX Identifier: Apache-2.0
 
+using System.Diagnostics;
+
 using Valkey.Glide.Internals;
 
 using static Valkey.Glide.Commands.Options.InfoOptions;
+using static Valkey.Glide.Errors;
 
 using RequestType = Valkey.Glide.Internals.FFI.RequestType;
 
@@ -25,45 +28,85 @@ namespace Valkey.Glide.Pipeline;
 public abstract class BaseBatch<T>(bool isAtomic) : IBatch where T : BaseBatch<T>
 {
     private readonly List<FFI.Cmd> _commands = [];
+    private readonly List<Func<object?, object?>> _converters = [];
 
     internal bool IsAtomic { get; private set; } = isAtomic;
 
     internal FFI.Batch ToFFI() => new([.. _commands], IsAtomic);
 
-    /// <inheritdoc cref="IBatch.CustomCommand(GlideString[])" />
-    public T CustomCommand(GlideString[] args)
+    /// <summary>
+    /// Convert a response reseived from the server.
+    /// </summary>
+    internal object?[]? ConvertResponse(object?[]? response)
     {
-        _commands.Add(new(RequestType.CustomCommand, args));
-        return (T)this;
+        if (response is null)
+        {
+            return null;
+        }
+
+        Debug.Assert(response?.Length == _converters.Count, "Converteds misaligned");
+
+        for (int i = 0; i < response?.Length; i++)
+        {
+            response[i] = _converters[i](response[i]);
+        }
+        return response;
     }
 
-    /// <inheritdoc cref="IBatch.Get(GlideString)" />
-    public T Get(GlideString key)
+    /// <summary>
+    /// Create a type checker for the response value.
+    /// </summary>
+    /// <typeparam name="V">Expected value type</typeparam>
+    protected Func<object?, object?> MakeTypeChecker<V>(bool isNullable = false) where V : class?
+        => MakeTypeCheckerAndConverter<V, V>(r => r, isNullable);
+
+    /// <summary>
+    /// Create a function which checks response value type and converts it.
+    /// </summary>
+    /// <typeparam name="V">Expected value type in server response</typeparam>
+    /// <typeparam name="R">Resulting value type after conversion</typeparam>
+    protected Func<object?, object?> MakeTypeCheckerAndConverter<V, R>(Func<V, R> converter, bool isNullable = false) where V : class? where R : class?
+        => value =>
+        {
+#pragma warning disable IDE0046 // Convert to conditional expression
+            if (value is null)
+            {
+                return isNullable
+                    ? null
+                    : (object)new RequestException($"Unexpected return type from Glide: got null expected {typeof(V).GetRealTypeName()}");
+            }
+#pragma warning restore IDE0046 // Convert to conditional expression
+            return value is V
+                ? converter((value as V)!)
+                : new RequestException($"Unexpected return type from Glide: got {value?.GetType().GetRealTypeName()} expected {typeof(V).GetRealTypeName()}");
+        };
+
+    internal T AddCmd(FFI.Cmd cmd, Func<object?, object?> converter)
     {
-        _commands.Add(new(RequestType.Get, [key]));
+        _commands.Add(cmd);
+        _converters.Add(converter);
         return (T)this;
     }
 
+    /// <inheritdoc cref="IBatch.CustomCommand(GlideString[])" />
+    public T CustomCommand(GlideString[] args)
+        => AddCmd(new(RequestType.CustomCommand, args), MakeTypeChecker<object>(true));
+
+    /// <inheritdoc cref="IBatch.Get(GlideString)" />
+    public T Get(GlideString key)
+        => AddCmd(new(RequestType.Get, [key]), MakeTypeChecker<GlideString>(true));
+
     /// <inheritdoc cref="IBatch.Set(GlideString, GlideString)" />
     public T Set(GlideString key, GlideString value)
-    {
-        _commands.Add(new(RequestType.Set, [key, value]));
-        return (T)this;
-    }
+        => AddCmd(new(RequestType.Set, [key, value]), MakeTypeChecker<string>());
 
     /// <inheritdoc cref="IBatch.Info()" />
-    public T Info()
-    {
-        _commands.Add(new(RequestType.Info, []));
-        return (T)this;
-    }
+    public T Info() => Info([]);
 
     /// <inheritdoc cref="IBatch.Info(Section[])" />
     public T Info(Section[] sections)
-    {
-        _commands.Add(new(RequestType.Info, sections.ToGlideStrings()));
-        return (T)this;
-    }
+        => AddCmd(new(RequestType.Info, sections.ToGlideStrings()),
+            MakeTypeCheckerAndConverter<GlideString, string>(gs => gs.ToString()));
 
     IBatch IBatch.CustomCommand(GlideString[] args) => CustomCommand(args);
     IBatch IBatch.Get(GlideString key) => Get(key);

csharp/tests/Valkey.Glide.IntegrationTests/ClusterClientTests.cs

@@ -105,19 +105,19 @@ public async Task BatchWithSingleNodeRoute(bool isAtomic)
         ClusterBatch batch = new ClusterBatch(isAtomic).Info([Section.REPLICATION]);
 
         object?[]? res = await client.Exec(batch, true, new(route: new SlotKeyRoute("abc", SlotType.Primary)));
-        Assert.Contains("role:master", res![0] as gs);
+        Assert.Contains("role:master", res![0] as string);
 
         res = await client.Exec(batch, true, new(route: new SlotKeyRoute("abc", SlotType.Replica)));
-        Assert.Contains("role:slave", res![0] as gs);
+        Assert.Contains("role:slave", res![0] as string);
 
         res = await client.Exec(batch, true, new(route: new SlotIdRoute(42, SlotType.Primary)));
-        Assert.Contains("role:master", res![0] as gs);
+        Assert.Contains("role:master", res![0] as string);
 
         res = await client.Exec(batch, true, new(route: new SlotIdRoute(42, SlotType.Replica)));
-        Assert.Contains("role:slave", res![0] as gs);
+        Assert.Contains("role:slave", res![0] as string);
 
         res = await client.Exec(batch, true, new(route: new ByAddressRoute(TestConfiguration.CLUSTER_HOSTS[0].host, TestConfiguration.CLUSTER_HOSTS[0].port)));
-        Assert.Contains("# Replication", res![0] as gs);
+        Assert.Contains("# Replication", res![0] as string);
     }
 
     [Fact]