fix: Fix multi-spec generation issues for CLI

- Add namespace prefix to UnixTimestampJsonConverter file name to prevent
  overwrites when generating multiple specs to the same directory
- Remove UnixTimestampJsonConverter from AsyncAPI converters list (not needed)
- Fix value type deserialization in WebSocket receive method to use
  non-generic Deserialize overload compatible with JsonSerializerContext
- Add --json-serializer-context CLI option for custom context class names
- Extract context class name from Settings.JsonSerializerContext property

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: HavenDV

src/libs/AutoSDK.CLI/Commands/GenerateCommand.cs

@@ -145,6 +145,13 @@ internal sealed class GenerateCommand : Command
         Description = "Override class name for the generated WebSocket client (AsyncAPI specs only).",
     };
 
+    private Option<string> JsonSerializerContextName { get; } = new(
+        name: "--json-serializer-context")
+    {
+        DefaultValueFactory = _ => string.Empty,
+        Description = "Override the JsonSerializerContext class name (default: SourceGenerationContext). Useful when generating multiple specs to the same project.",
+    };
+
     public GenerateCommand() : base(name: "generate", description: "Generates client sdk using an OpenAPI or AsyncAPI spec.")
     {
         Arguments.Add(Input);
@@ -165,6 +172,7 @@ internal sealed class GenerateCommand : Command
         Options.Add(BaseUrl);
         Options.Add(OpenApiOverrides);
         Options.Add(WebSocketClientClassName);
+        Options.Add(JsonSerializerContextName);
 
         SetAction(HandleAsync);
     }
@@ -176,7 +184,11 @@ private async Task HandleAsync(ParseResult parseResult)
         bool singleFile = parseResult.GetRequiredValue(SingleFile);
 
         var namespaceValue = parseResult.GetRequiredValue(Namespace);
-        
+        var contextName = parseResult.GetRequiredValue(JsonSerializerContextName);
+        var contextClassName = string.IsNullOrWhiteSpace(contextName)
+            ? "SourceGenerationContext"
+            : contextName;
+
         Settings settings = Settings.Default with
         {
             TargetFramework = parseResult.GetRequiredValue(TargetFramework),
@@ -185,7 +197,7 @@ private async Task HandleAsync(ParseResult parseResult)
             ClsCompliantEnumPrefix = parseResult.GetRequiredValue(ClsCompliantEnumPrefix),
             MethodNamingConvention = parseResult.GetRequiredValue(MethodNamingConvention),
             ExcludeDeprecatedOperations = parseResult.GetRequiredValue(ExcludeDeprecatedOperations),
-            JsonSerializerContext = $"{namespaceValue}.SourceGenerationContext",
+            JsonSerializerContext = $"{namespaceValue}.{contextClassName}",
             GenerateJsonSerializerContextTypes = true,
             ComputeDiscriminators = parseResult.GetRequiredValue(ComputeDiscriminators),
             GenerateModelValidationMethods = parseResult.GetRequiredValue(GenerateModelValidationMethods),

src/libs/AutoSDK/Sources/AsyncApiData.cs

@@ -650,10 +650,6 @@ private static ImmutableArray<string> BuildConverters(
                     $"global::{settings.Namespace}.JsonConverters.{x.AnyOfData?.SubType}JsonConverter<{string.Join(", ", x.Children
                         .Where(y => y.Hint == (x.IsAnyOf ? Hint.AnyOf : x.IsOneOf ? Hint.OneOf : Hint.AllOf))
                         .Select(y => y.TypeData.CSharpTypeWithNullabilityForValueTypes))}>"))
-            .Concat(new[]
-            {
-                $"global::{globalSettings.Namespace}.JsonConverters.UnixTimestampJsonConverter",
-            })
             .ToImmutableArray();
     }
 }

src/libs/AutoSDK/Sources/Sources.JsonSerializerContext.cs

@@ -18,6 +18,11 @@ public static string GenerateJsonSerializerContext(
             return string.Empty;
         }
 
+        // Extract class name from fully-qualified JsonSerializerContext setting
+        var contextClassName = client.Settings.JsonSerializerContext.Contains(".")
+            ? client.Settings.JsonSerializerContext.Substring(client.Settings.JsonSerializerContext.LastIndexOf('.') + 1)
+            : "SourceGenerationContext";
+
         return $@"
 #nullable enable
 
@@ -36,7 +41,7 @@ namespace {client.Settings.Namespace}
 ").Inject()}
         }})]
 {(types.IsEmpty ? " " : GenerateJsonSerializableAttributes(client, types))}
-    public sealed partial class SourceGenerationContext : global::System.Text.Json.Serialization.JsonSerializerContext
+    public sealed partial class {contextClassName} : global::System.Text.Json.Serialization.JsonSerializerContext
     {{
     }}
 }}".RemoveBlankLinesWhereOnlyWhitespaces();

src/libs/AutoSDK/Sources/Sources.WebSocketReceiveMethod.cs

@@ -32,10 +32,10 @@ public static string GenerateWebSocketReceiveMethod(
         string deserializeAndYield;
         if (isValueType)
         {
-            // Value types (structs/anyOf) — Deserialize<T> returns T directly, no null check needed
+            // Value types (structs/anyOf) — use non-generic Deserialize with cast (no null check needed for value types)
             var deserializeCall = hasOptions
                 ? $"global::System.Text.Json.JsonSerializer.Deserialize<{eventTypeName}>(json, JsonSerializerOptions)"
-                : $"global::System.Text.Json.JsonSerializer.Deserialize<{eventTypeName}>(json, JsonSerializerContext)";
+                : $"({eventTypeName})global::System.Text.Json.JsonSerializer.Deserialize(json, typeof({eventTypeName}), JsonSerializerContext)!";
             deserializeAndYield = $@"                    var @event = {deserializeCall};
 
                     yield return @event;";

src/libs/AutoSDK/Sources/Sources.cs

@@ -234,7 +234,7 @@ public static FileWithName UnixTimestampJsonConverter(
         CancellationToken cancellationToken = default)
     {
         return new FileWithName(
-            Name: "JsonConverters.UnixTimestamp.g.cs",
+            Name: $"{settings.Namespace}.JsonConverters.UnixTimestamp.g.cs",
             Text: GenerateUnixTimestampJsonConverter(settings, cancellationToken: cancellationToken));
     }
 

…onConverters.UnixTimestamp.g.verified.cs …onConverters.UnixTimestamp.g.verified.cssrc/tests/AutoSDK.SnapshotTests/Snapshots/CLI/Empty/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/Empty/_#G.JsonConverters.UnixTimestamp.g.verified.cs src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/Empty/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/Empty/_#G.JsonConverters.UnixTimestamp.g.verified.cs

@@ -1,4 +1,4 @@
-//HintName: JsonConverters.UnixTimestamp.g.cs
+//HintName: G.JsonConverters.UnixTimestamp.g.cs
 #nullable enable
 
 namespace G.JsonConverters

…onConverters.UnixTimestamp.g.verified.cs …onConverters.UnixTimestamp.g.verified.cssrc/tests/AutoSDK.SnapshotTests/Snapshots/CLI/anthropic/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/anthropic/_#G.JsonConverters.UnixTimestamp.g.verified.cs src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/anthropic/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/anthropic/_#G.JsonConverters.UnixTimestamp.g.verified.cs

@@ -1,4 +1,4 @@
-//HintName: JsonConverters.UnixTimestamp.g.cs
+//HintName: G.JsonConverters.UnixTimestamp.g.cs
 #nullable enable
 
 namespace G.JsonConverters

…onConverters.UnixTimestamp.g.verified.cs …onConverters.UnixTimestamp.g.verified.cssrc/tests/AutoSDK.SnapshotTests/Snapshots/CLI/assemblyai/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/assemblyai/_#G.JsonConverters.UnixTimestamp.g.verified.cs src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/assemblyai/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/assemblyai/_#G.JsonConverters.UnixTimestamp.g.verified.cs

@@ -1,4 +1,4 @@
-//HintName: JsonConverters.UnixTimestamp.g.cs
+//HintName: G.JsonConverters.UnixTimestamp.g.cs
 #nullable enable
 
 namespace G.JsonConverters

…onConverters.UnixTimestamp.g.verified.cs …onConverters.UnixTimestamp.g.verified.cssrc/tests/AutoSDK.SnapshotTests/Snapshots/CLI/circular-refs/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/circular-refs/_#G.JsonConverters.UnixTimestamp.g.verified.cs src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/circular-refs/_#JsonConverters.UnixTimestamp.g.verified.cs renamed to src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/circular-refs/_#G.JsonConverters.UnixTimestamp.g.verified.cs

@@ -1,4 +1,4 @@
-//HintName: JsonConverters.UnixTimestamp.g.cs
+//HintName: G.JsonConverters.UnixTimestamp.g.cs
 #nullable enable
 
 namespace G.JsonConverters

src/tests/AutoSDK.SnapshotTests/Snapshots/CLI/cohere/_#G.JsonConverters.UnixTimestamp.g.verified.cs

@@ -0,0 +1,45 @@
+//HintName: G.JsonConverters.UnixTimestamp.g.cs
+#nullable enable
+
+namespace G.JsonConverters
+{
+    /// <inheritdoc />
+    public class UnixTimestampJsonConverter : global::System.Text.Json.Serialization.JsonConverter<global::System.DateTimeOffset>
+    {
+        /// <inheritdoc />
+        public override global::System.DateTimeOffset Read(
+            ref global::System.Text.Json.Utf8JsonReader reader,
+            global::System.Type typeToConvert,
+            global::System.Text.Json.JsonSerializerOptions options)
+        {
+            if (reader.TokenType == global::System.Text.Json.JsonTokenType.Number)
+            {
+                if (reader.TryGetInt64(out long unixTimestamp))
+                {
+                    if (unixTimestamp >= -62135596800L && unixTimestamp <= 253402300799L)
+                    {
+                        return global::System.DateTimeOffset.FromUnixTimeSeconds(unixTimestamp);
+                    }
+                    
+                    return global::System.DateTimeOffset.FromUnixTimeMilliseconds(unixTimestamp);
+                }
+                if (reader.TryGetInt32(out int unixTimestampInt))
+                {
+                    return global::System.DateTimeOffset.FromUnixTimeSeconds(unixTimestampInt);
+                }
+            }
+
+            return default;
+        }
+
+        /// <inheritdoc />
+        public override void Write(
+            global::System.Text.Json.Utf8JsonWriter writer,
+            global::System.DateTimeOffset value,
+            global::System.Text.Json.JsonSerializerOptions options)
+        {
+            long unixTimestamp = value.ToUnixTimeSeconds();
+            writer.WriteNumberValue(unixTimestamp);
+        }
+    }
+}