From a06ee6b158f2ae5157259df61230602833c4fef8 Mon Sep 17 00:00:00 2001
From: Stef Heyenrath <Stef.Heyenrath@gmail.com>
Date: Sat, 12 Jul 2025 11:05:02 +0200
Subject: [PATCH] Fix HandlebarsContext.ParseAndEvaluate (#1329)

---
 .../Transformers/Handlebars/HandlebarsContext.cs     |  8 +++++---
 .../ResponseBuilders/ResponseWithTransformerTests.cs | 12 ++++++------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/WireMock.Net.Minimal/Transformers/Handlebars/HandlebarsContext.cs b/src/WireMock.Net.Minimal/Transformers/Handlebars/HandlebarsContext.cs
index 57632ba3..e94f93a7 100644
--- a/src/WireMock.Net.Minimal/Transformers/Handlebars/HandlebarsContext.cs
+++ b/src/WireMock.Net.Minimal/Transformers/Handlebars/HandlebarsContext.cs
@@ -1,5 +1,6 @@
 // Copyright © WireMock.Net
 
+using System.Text.RegularExpressions;
 using HandlebarsDotNet;
 using HandlebarsDotNet.Helpers.Extensions;
 using Stef.Validation;
@@ -9,6 +10,8 @@ namespace WireMock.Transformers.Handlebars;
 
 internal class HandlebarsContext : IHandlebarsContext
 {
+    private static readonly Regex _tryEvaluateRegex = new(@"\{\{.*?\}\}", RegexOptions.Compiled);
+
     public IHandlebars Handlebars { get; }
 
     public IFileSystemHandler FileSystemHandler { get; }
@@ -27,9 +30,8 @@ internal class HandlebarsContext : IHandlebarsContext
 
     public object? ParseAndEvaluate(string text, object model)
     {
-        if (text.StartsWith("{{") && text.EndsWith("}}") &&
-            Handlebars.TryEvaluate(text, model, out var result) &&
-            result is not UndefinedBindingResult)
+        // Only try to evaluate if the text matches the pattern `{{ xxx }}` exactly once.
+        if (_tryEvaluateRegex.Matches(text).Count == 1 && Handlebars.TryEvaluate(text, model, out var result) && result is not UndefinedBindingResult)
         {
             return result;
         }
diff --git a/test/WireMock.Net.Tests/ResponseBuilders/ResponseWithTransformerTests.cs b/test/WireMock.Net.Tests/ResponseBuilders/ResponseWithTransformerTests.cs
index d6727acd..9f663fd0 100644
--- a/test/WireMock.Net.Tests/ResponseBuilders/ResponseWithTransformerTests.cs
+++ b/test/WireMock.Net.Tests/ResponseBuilders/ResponseWithTransformerTests.cs
@@ -120,21 +120,21 @@ public class ResponseWithTransformerTests
         var request = new RequestMessage(urlDetails, "POST", ClientIp);
 
         var responseBuilder = Response.Create()
-            .WithBody("{{request.PathSegments.[0]}} {{request.AbsolutePathSegments.[0]}}")
+            .WithBody("{{request.PathSegments.[0]}} {{request.PathSegments.[1]}} {{request.AbsolutePathSegments.[0]}}")
             .WithTransformer();
 
         // Act
         var response = await responseBuilder.ProvideResponseAsync(_mappingMock.Object, request, _settings).ConfigureAwait(false);
 
         // Assert
-        Check.That(response.Message.BodyData!.BodyAsString).Equals("a wiremock");
+        Check.That(response.Message.BodyData!.BodyAsString).Equals("a b wiremock");
     }
 
     [Theory]
-    [InlineData("{{request.PathSegments.[0]}}", "a")]
-    [InlineData("prefix_{{request.PathSegments.[0]}}", "prefix_a")]
-    [InlineData("{{request.PathSegments.[0]}}_postfix", "a_postfix")]
-    [InlineData("prefix_{{request.PathSegments.[0]}}_postfix", "prefix_a_postfix")]
+    [InlineData("{{request.PathSegments.[0]}} {{request.PathSegments.[1]}}", "a b")]
+    [InlineData("prefix_{{request.PathSegments.[0]}} {{request.PathSegments.[1]}}", "prefix_a b")]
+    [InlineData("{{request.PathSegments.[0]}} {{request.PathSegments.[1]}}_postfix", "a b_postfix")]
+    [InlineData("prefix_{{request.PathSegments.[0]}} {{request.PathSegments.[1]}}_postfix", "prefix_a b_postfix")]
     public async Task Response_ProvideResponse_Handlebars_BodyAsJson_PathSegments(string field, string expected)
     {
         // Assign