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Improved context in lambda #153

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59026b9
improved context in lambda
Mar 29, 2026
63ffb2b
add a test to ensure existing behavior does not change
Mar 31, 2026
aaa77e2
rename tests
Mar 31, 2026
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33 changes: 27 additions & 6 deletions src/Stubble.Core/Renderers/StringRenderer/TokenRenderers/SectionTokenRenderer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,7 @@ protected override void Write(StringRender renderer, SectionToken obj, Context c
else if (LambdaTypes.Contains(value.GetType()))
{
var sectionContent = obj.SectionContent.ToString();
var lambdaView = FindNearestObjectView(context);

switch (value)
{
Expand All @@ -73,13 +74,13 @@ protected override void Write(StringRender renderer, SectionToken obj, Context c
case Func<string, Func<string, Task<string>>, Task<object>> _:
throw new StubbleException("Async lambdas are not allowed in non-async template rendering");
case Func<dynamic, string, object> func:
value = func(context.View, sectionContent);
value = func(lambdaView, sectionContent);
break;
case Func<string, object> func:
value = func(sectionContent);
break;
case Func<dynamic, string, Func<string, string>, object> func:
value = func(context.View, sectionContent, RenderInContext(context, obj.Tags));
value = func(lambdaView, sectionContent, RenderInContext(context, obj.Tags));
break;
case Func<string, Func<string, string>, object> func:
value = func(sectionContent, RenderInContext(context, obj.Tags));
Expand Down Expand Up @@ -127,14 +128,15 @@ protected override async Task WriteAsync(StringRender renderer, SectionToken obj
else if (LambdaTypes.Contains(value.GetType()))
{
var sectionContent = obj.SectionContent.ToString();
var lambdaView = FindNearestObjectView(context);

switch (value)
{
case Func<dynamic, string, Task<object>> func:
value = await func(context.View, sectionContent).ConfigureAwait(false);
value = await func(lambdaView, sectionContent).ConfigureAwait(false);
break;
case Func<dynamic, string, object> func:
value = func(context.View, sectionContent);
value = func(lambdaView, sectionContent);
break;
case Func<string, Task<object>> func:
value = await func(sectionContent).ConfigureAwait(false);
Expand All @@ -143,10 +145,10 @@ protected override async Task WriteAsync(StringRender renderer, SectionToken obj
value = func(sectionContent);
break;
case Func<dynamic, string, Func<string, Task<string>>, Task<object>> func:
value = await func(context.View, sectionContent, RenderInContextAsync(context, obj.Tags)).ConfigureAwait(false);
value = await func(lambdaView, sectionContent, RenderInContextAsync(context, obj.Tags)).ConfigureAwait(false);
break;
case Func<dynamic, string, Func<string, string>, object> func:
value = func(context.View, sectionContent, RenderInContext(context, obj.Tags));
value = func(lambdaView, sectionContent, RenderInContext(context, obj.Tags));
break;
case Func<string, Func<string, Task<string>>, Task<object>> func:
value = await func(sectionContent, RenderInContextAsync(context, obj.Tags)).ConfigureAwait(false);
Expand All @@ -165,6 +167,25 @@ protected override async Task WriteAsync(StringRender renderer, SectionToken obj
}
}

private static dynamic FindNearestObjectView(Context context)
{
var current = context;
while (current != null)
{
var view = current.View;
if (view != null && !(view is bool) && !(view is int) && !(view is long)
&& !(view is float) && !(view is double) && !(view is decimal)
&& !(view is string))
{
return view;
}

current = current.ParentContext;
}

return context.View;
}

private Func<string, string> RenderInContext(Context context, Classes.Tags tags)
{
return (str) =>
Expand Down
58 changes: 56 additions & 2 deletions test/Stubble.Core.Tests/Renderers/StringRenderer/SectionTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,8 +13,8 @@
using Stubble.Core.Settings;
using Stubble.Core.Tokens;
using Xunit;
using Stubble.Core.Contexts;
using Stubble.Core.Contexts;

namespace Stubble.Core.Tests.Renderers.StringRenderer
{
public class SectionTests : RendererTestsBase
Expand Down Expand Up @@ -328,5 +328,59 @@ public void It_Can_Render_LambdaTags_UsingOriginalTemplate()
var myStr = sr.ReadToEnd();
Assert.Equal(result, myStr);
}

[Fact]
public void It_Can_Render_ThreeArgLambda_InsideBooleanSection_WithNearestObjectView()
{
var stubble = new Stubble.Core.Builders.StubbleBuilder().Build();

dynamic capturedView = null;
var data = new Dictionary<string, object>
{
{ "showSection", true },
{ "greeting", "Hello" },
{
"myLambda",
new Func<dynamic, string, Func<string, string>, object>((ctx, tmpl, render) =>
{
capturedView = ctx;
return render(tmpl);
})
}
};

var templateStr = "{{#showSection}}{{#myLambda}}{{greeting}}{{/myLambda}}{{/showSection}}";
var result = stubble.Render(templateStr, data);

Assert.Equal("Hello", result);
// The lambda should receive the root data dictionary (nearest object view),
// not the boolean value 'true' from the showSection context.
Assert.IsAssignableFrom<IDictionary<string, object>>(capturedView);
}

[Fact]
public void It_Can_Render_ThreeArgLambda_InsideBooleanSection_DotResolvesToBool()
{
var stubble = new Stubble.Core.Builders.StubbleBuilder().Build();

var data = new Dictionary<string, object>
{
{ "showSection", true },
{
"myLambda",
new Func<dynamic, string, Func<string, string>, object>((ctx, tmpl, render) =>
{
return render(tmpl);
})
}
};

// {{.}} inside a boolean section should still resolve to "True",
// even though FindNearestObjectView passes the parent dict to the lambda.
var templateStr = "{{#showSection}}{{#myLambda}}{{.}}{{/myLambda}}{{/showSection}}";
var result = stubble.Render(templateStr, data);

Assert.Equal("True", result);
}
}
}
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