Null refrence exception for RenderingExtensions.IsSerializable

Question

Sitecore 9.3 JSS

What is happening: Many a time, we are getting 500 from the layout service. In the log we have the following entry:

ERROR Exception during Layout Service RenderItem (configuration: jss, item: /)
Exception: System.NullReferenceException
Message: Object reference not set to an instance of an object.
Source: Sitecore.LayoutService
   at Sitecore.LayoutService.Extensions.RenderingExtensions.IsSerializable(Rendering rendering, IEnumerable`1 serializableRenderingTypes)
   at Sitecore.LayoutService.Pipelines.GetRenderer.GetJsonRenderer.Process(GetRendererArgs args)
   at Sitecore.JavaScriptServices.ViewEngine.Pipelines.Response.GetRenderer.GetJsonRenderer.Process(GetRendererArgs args)
   at (Object , Object )
   at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain, Boolean failIfNotExists)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain)
   at Sitecore.Mvc.Pipelines.PipelineService.RunPipeline[TArgs](String pipelineName, TArgs args)
   at Sitecore.Mvc.Pipelines.PipelineService.RunPipeline[TArgs,TResult](String pipelineName, TArgs args, Func`2 resultGetter)
   at Sitecore.Mvc.Presentation.Rendering.GetRenderer()
   at Sitecore.Mvc.Presentation.Rendering.get_Renderer()
   at Sitecore.Mvc.Pipelines.Response.RenderPlaceholder.PerformRendering.CreateCyclePreventer(String placeholderName, Rendering rendering)
   at Sitecore.Mvc.Pipelines.Response.RenderPlaceholder.PerformRendering.Render(String placeholderName, TextWriter writer, RenderPlaceholderArgs args)
   at (Object , Object )
   at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain, Boolean failIfNotExists)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain)
   at Sitecore.LayoutService.ItemRendering.PlaceholderRenderingService.RenderPlaceholder(PlaceholderDefinition placeholderDefinition, IRenderingConfiguration renderingConfiguration)
   at System.Linq.Enumerable.WhereSelectListIterator`2.MoveNext()
   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Sitecore.LayoutService.ItemRendering.LayoutService.Render(Item item, IRenderingConfiguration renderingConfiguration, RenderOptions renderOptions)
   at Sitecore.LayoutService.Mvc.Controllers.LayoutServiceController.RenderItem(String configuration, String item)

When we make any change in the placeholder in the shared layout and publish it, the issue gets resolved. Though this re-occurs after some time.

I have tried by disabling all the components from the final-layout to rule-out any issue with the components.

Answer 1

We have been able to have a way around. The way around is:

1. Change the placeholder for any of the renderings.
2. Publish the item.
3. Revert the change in point 1.
4. Publish the item