From 51b5a7149a7d5a18a327b164ae550f8fd242bbb7 Mon Sep 17 00:00:00 2001
From: Rex Morgan <rex@rexmorgan.net>
Date: Fri, 19 Jun 2026 20:54:38 -0400
Subject: [PATCH] fix: parent context traversal inside custom block helpers in
 each (issue #539)

When options.Template/Inverse was called with a Context struct argument, it
unwrapped context.Value and created a new child frame, adding an extra level
to the parent chain. This caused ../ inside the block helper's template to
resolve to the current iteration item rather than its parent.

Fix: pass Frame directly when Template/Inverse receives a Context struct, since
Frame already represents the correct current binding context.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 source/Handlebars.Test/IssueTests.cs    | 21 +++++++++++++++++++++
 source/Handlebars/BlockHelperOptions.cs |  4 ++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/source/Handlebars.Test/IssueTests.cs b/source/Handlebars.Test/IssueTests.cs
index 31136117..10d653fe 100644
--- a/source/Handlebars.Test/IssueTests.cs
+++ b/source/Handlebars.Test/IssueTests.cs
@@ -733,5 +733,26 @@ public void UnrecognisedExpressionThrowsOutOfMemoryException()
 
             Assert.Throws<HandlebarsCompilerException>(()=> Handlebars.Compile(source));
         }
+
+        // Issue: https://github.com/Handlebars-Net/Handlebars.Net/issues/539
+        // Parent context (../) resolves to wrong value inside a custom block helper used within #each
+        [Fact]
+        public void Issue539_ParentContextInsideCustomBlockHelperInEach()
+        {
+            var handlebars = Handlebars.Create();
+            handlebars.RegisterHelper("ifCond", (writer, options, context, parameters) =>
+            {
+                if (parameters.Length == 3 && parameters[0]?.ToString() == parameters[2]?.ToString())
+                    options.Template(writer, context);
+                else
+                    options.Inverse(writer, context);
+            });
+
+            var source = @"{{#each loop}}{{#ifCond another '===' 'value'}}{{../this.foo}}{{/ifCond}}{{/each}}";
+            var template = handlebars.Compile(source);
+            var data = new { foo = "bar", loop = new object[] { new { another = "value" } } };
+            var result = template(data);
+            Assert.Equal("bar", result.Trim());
+        }
     }
 }
\ No newline at end of file
diff --git a/source/Handlebars/BlockHelperOptions.cs b/source/Handlebars/BlockHelperOptions.cs
index 57253922..86f12813 100644
--- a/source/Handlebars/BlockHelperOptions.cs
+++ b/source/Handlebars/BlockHelperOptions.cs
@@ -71,7 +71,7 @@ public void Template(in EncodedTextWriter writer, object context)
         /// BlockHelper body
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void Template(in EncodedTextWriter writer, in Context context) => Template(writer, context.Value);
+        public void Template(in EncodedTextWriter writer, in Context context) => OriginalTemplate(writer, Frame);
         
         /// <summary>
         /// BlockHelper body
@@ -113,7 +113,7 @@ public void Inverse(in EncodedTextWriter writer, object context)
         /// BlockHelper body
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void Inverse(in EncodedTextWriter writer, in Context context) => Inverse(writer, context.Value);
+        public void Inverse(in EncodedTextWriter writer, in Context context) => OriginalInverse(writer, Frame);
         
         /// <summary>
         /// BlockHelper body