Dispose will reset the state to not lead to undefined behavior

Author: linkdotnet

CHANGELOG.md

@@ -6,6 +6,9 @@ All notable changes to **ValueStringBuilder** will be documented in this file. T
 
 ## [Unreleased]
 
+### Changed
+- `Dispose` resets the `ValueStringBuilder` to the initial state, so it doesn't lead to undefined behavior when used again
+
 ## [1.18.5] - 2023-10-19
 
 ### Changed

src/LinkDotNet.StringBuilder/ValueStringBuilder.cs

@@ -286,12 +286,14 @@ public readonly int LastIndexOf(ReadOnlySpan<char> word, int startIndex)
     /// Disposes the instance and returns rented buffer from an array pool if needed.
     /// </summary>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public readonly void Dispose()
+    public void Dispose()
     {
         if (arrayFromPool != null)
         {
             ArrayPool<char>.Shared.Return(arrayFromPool);
         }
+
+        this = default;
     }
 
     /// <summary>

tests/LinkDotNet.StringBuilder.UnitTests/ValueStringBuilderTests.cs

@@ -503,4 +503,14 @@ public void GivenAString_WhenEnumerating_ThenShouldReturnCharacters()
 
         output.Should().Be("Hello World");
     }
+
+    [Fact]
+    public void GivenStringBuilder_WhenDisposed_ThenEmtpyStringReturned()
+    {
+        var builder = new ValueStringBuilder("Hello World");
+
+        builder.Dispose();
+
+        builder.ToString().Should().Be(string.Empty);
+    }
 }