Using named arguments in partials in nested loop causes error

[glenntKF]

Describe the bug

Hi, we have started using Handlebars.net and it is a great library. We are running into an issue where using named arguments in a partial when in a nested loop causes an error. We are using a JsonDocument from System.Text.Json as the model for the template.

Expected behavior:

Partials in nested loops with named arguments should not cause errors when used.

Test to reproduce

{{#each items }}
{{#each this.nested}}
{{> myPartial arg1=value1 arg2=value2 }}
{{/each}
{{/each}}

Other related info

Stack trace
HandlebarsDotNet.HandlebarsRuntimeException: Runtime error while rendering partial 'local/details', see inner exception for more information
---> System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
at HandlebarsDotNet.Extension.Json.Utils.GetEnumerator(JsonElement document)
at HandlebarsDotNet.BindingContext.PopulateHash(HashParameterDictionary hash, Object from)
at HandlebarsDotNet.BindingContext.Initialize()
at HandlebarsDotNet.BindingContext.BindingContextPool.CreateContext(ICompiledHandlebarsConfiguration configuration, Object value, BindingContext parent, TemplateDelegate partialBlockTemplate)
at lambda_method240(Closure , EncodedTextWriter& , BindingContext )
at HandlebarsDotNet.Extension.Json.JsonElementIterator.IterateArray(EncodedTextWriter& writer, BindingContext context, ChainSegment[] blockParamsVariables, JsonElement target, TemplateDelegate template, TemplateDelegate ifEmpty)
at HandlebarsDotNet.Extension.Json.JsonElementIterator.HandlebarsDotNet.Iterators.IIterator.Iterate(EncodedTextWriter& writer, BindingContext context, ChainSegment[] blockParamsVariables, Object input, TemplateDelegate template, TemplateDelegate ifEmpty)
at HandlebarsDotNet.Compiler.Iterator.Iterate(BindingContext context, EncodedTextWriter writer, ChainSegment[] blockParamsVariables, Object target, TemplateDelegate template, TemplateDelegate ifEmpty)
at lambda_method241(Closure , EncodedTextWriter& , BindingContext )
at HandlebarsDotNet.Extension.Json.JsonElementIterator.IterateArray(EncodedTextWriter& writer, BindingContext context, ChainSegment[] blockParamsVariables, JsonElement target, TemplateDelegate template, TemplateDelegate ifEmpty)
at HandlebarsDotNet.Extension.Json.JsonElementIterator.HandlebarsDotNet.Iterators.IIterator.Iterate(EncodedTextWriter& writer, BindingContext context, ChainSegment[] blockParamsVariables, Object input, TemplateDelegate template, TemplateDelegate ifEmpty)
at HandlebarsDotNet.Compiler.Iterator.Iterate(BindingContext context, EncodedTextWriter writer, ChainSegment[] blockParamsVariables, Object target, TemplateDelegate template, TemplateDelegate ifEmpty)
at lambda_method242(Closure , EncodedTextWriter& , BindingContext )
at HandlebarsDotNet.HandlebarsEnvironment.<>c__DisplayClass15_0.b__0(TextWriter writer, Object context, Object data)
at HandlebarsDotNet.Compiler.PartialBinder.InvokePartial(String partialName, BindingContext context, EncodedTextWriter writer, ICompiledHandlebarsConfiguration configuration)
--- End of inner exception stack trace ---
at HandlebarsDotNet.Compiler.PartialBinder.InvokePartial(String partialName, BindingContext context, EncodedTextWriter writer, ICompiledHandlebarsConfiguration configuration)
at HandlebarsDotNet.Compiler.PartialBinder.InvokePartialWithFallback(String partialName, BindingContext context, EncodedTextWriter writer, ICompiledHandlebarsConfiguration configuration)
at lambda_method253(Closure , EncodedTextWriter& , BindingContext )
at HandlebarsDotNet.HandlebarsEnvironment.<>c__DisplayClass15_0.b__0(TextWriter writer, Object context, Object data)
at HandlebarsDotNet.HandlebarsEnvironment.<>c__DisplayClass16_0.b__0(Object context, Object data)
at Reports.Services.TemplatingService.GenerateReportHtmlAsync(Manifest manifest, JsonDocument reportJson) in /Users/gtolenti/dev/bitbucket/kf-sell-platform/Reports/Services/TemplatingService.cs:line 57
at Reports.Services.ReportService.GenerateReportAsync(JsonDocument reportJson) in /Users/gtolenti/dev/bitbucket/kf-sell-platform/Reports/Services/ReportService.cs:line 93
at Reporting.Controllers.ReportsController.Post(JsonDocument reportJson) in /Users/gtolenti/dev/bitbucket/kf-sell-platform/Reports/Controllers/ReportsController.cs:line 47
at lambda_method7(Closure , Object )
at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at Serilog.AspNetCore.RequestLoggingMiddleware.Invoke(HttpContext httpContext)
at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

---

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[oformaniuk]

Hello @glenntKF
It would be very helpful if you provide a test that can reproduce the bug.

[glenntKF]

Hi @zjklee,

Thanks for the quick reply. Upon further testing it looks like it doesn't have anything to do with nested loops. It occurs in a loop where the JSON being iterated on is an array with values in it:

{
   "items": [
      "value1",
      "value2"
   ]
}

Below is a test case. We are using .net 5 core.

[Fact]
public void Handlebars_EachPartialError()
{
    // Arrange
    string jsonString = @"{
        ""items"": [
            ""item1"",
            ""item2""
        ]
    }";

    JsonDocument json = JsonSerializer.Deserialize<JsonDocument>(jsonString);

    IHandlebars handlebars = HandlebarsDotNet.Handlebars.Create();
    handlebars.Configuration.UseJson();

    string template = @"
        This is a template
        {{> local/myPartial value=""test partial value""}}
        {{#each items}}
            {{name}}          
            {{> local/myPartial value=name}}            
        {{/#each}}";

    handlebars.RegisterTemplate("local/myPartial", "This is a value {{value}}");

    var compiledTemplate = handlebars.Compile(template);

    var result = compiledTemplate(json);
    
    Assert.Equal("", "");
} 

If I wrap the values in the array with objects it works fine:

{
   "items": [
      {
         "value": "value1"
      },
      {
        "value": "value2"
      }
   ]
}

Thanks.