[Auto Maintainer Assistant] Prepare release 6.6.0

[github-actions]

🤖 This PR was created by the repository's automated AI maintenance assistant.

Summary

This PR updates RELEASE_NOTES.md to capture all changes merged since the 6.5.0 release (Mar 11, 2025) and marks version 6.6.0 as ready for release.

Changes included in 6.6.0

PR	Type	Description
#1596	🔒 Security	Fix potential XXE vulnerability in XML parsing (by @Thorium)
#1527	🐛 Bug fix	XML provider: use XDocument reader overload instead of ReadToEnd (by @Thorium, fixes #1501)
#1550	⚡ Performance	HTML parser: replace CharList linked-list with StringBuilder (~43% HTML parsing improvement)
#1562	⚡ Performance	JSON string serialization: bulk-write unescaped chars instead of char-by-char
#1540	⚡ Performance	RemoveAdorners: fast-path for strings without currency/percentage adorners
#1499	✨ Feature	HTML: compile-time opt-in to disable HIDE_REPRESENTATION define (by @smoothdeveloper)
#1597	📝 Docs	Fix links in documentation (by @kant2002)
#1581–#1594	🧪 Tests	Expanded test coverage across CSV, JSON, HTML, XML, and WorldBank modules

Version bump rationale (SemVer)

• No breaking changes → not major
• New feature (FSharp.Data.Html suggested change to enable people to use the html parser without hiding representation without having to hack the code itself. #1499), perf improvements, and security fix → minor bump is appropriate
• 6.5.0 → 6.6.0 ✓

Test Status

• Library build passes (dotnet build src/FSharp.Data/FSharp.Data.fsproj -c Release)
• Full solution tests could not be run: the FSharp.Data.Tests project uses the WorldBankProvider type provider at compile-time, which requires live HTTP access to api.worldbank.org. The CI environment has network egress blocked by a proxy (HTTP 403), causing design-time type provider failures in that test project only. This is an environment/infrastructure constraint, not a regression introduced by these changes (which are purely in RELEASE_NOTES.md).

Human maintainers should run dotnet test FSharp.Data.sln -c Release in an environment with network access before merging and tagging.

Checklist for maintainers before merging

• Review the changelog entries for accuracy
• Run dotnet test FSharp.Data.sln -c Release in an internet-connected environment
• Tag the commit as v6.6.0 after merge
• Publish NuGet packages

Generated by Auto Maintainer Assistant

Warning

⚠️ Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• api.worldbank.org

---

Note

This was originally intended as a pull request, but the git push operation failed.

Workflow Run: View run details and download patch artifact

The patch file is available in the agent-artifacts artifact in the workflow run linked above.

To apply the patch locally:

# Download the artifact from the workflow run https://github.com/fsprojects/FSharp.Data/actions/runs/22249619390
# (Use GitHub MCP tools if gh CLI is not available)
gh run download 22249619390 -n agent-artifacts -D /tmp/agent-artifacts-22249619390

# Apply the patch
git am /tmp/agent-artifacts-22249619390/aw.patch

Show patch preview (51 of 51 lines)

From 9f7b56ffdd926d542660d4c5f8a92d4a02904038 Mon Sep 17 00:00:00 2001
From: GitHub Copilot <copilot@github.com>
Date: Sat, 21 Feb 2026 03:45:26 +0000
Subject: [PATCH] Prepare release notes for 6.6.0

Consolidate all changes since 6.5.0 into RELEASE_NOTES.md
and mark 6.6.0 as released, opening 6.7.0 unreleased section.

Changes included in 6.6.0:
- Security fix: XXE vulnerability in XML parsing (#1596)
- Bug fix: XML provider uses XDocument reader instead of ReadToEnd (#1527)
- Performance: HTML parser CharList uses StringBuilder (~43% faster) (#1550)
- Performance: JSON string serialization bulk writes (#1562)
- Performance: RemoveAdorners fast-path for adorner-free strings (#1540)
- Feature: HTML HIDE_REPRESENTATION compile-time opt-in (#1499)
- Documentation: Fix links (#1597)
- Tests: Expanded coverage across all modules

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 RELEASE_NOTES.md | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 5f754145..3e00e860 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -1,7 +1,17 @@
 # Release Notes
 
-## 6.6.0 - Unreleased
-
+## 6.7.0 - Unreleased
+
+## 6.6.0 - Feb 21 2026
+
+- Fix potential XXE vulnerability in XML parsing by @Thorium in #1596
+- Fix XML provider to use XDocument reader overload instead of ReadToEnd by @Thorium in #1527
+- Optimize HTML parser CharList using StringBuilder (~43% HTML parsing improvement) in #1550
+- Optimize JSON string serialization to use bulk writes in #1562
+- Optimize string allocation in RemoveAdorners for adorner-free strings in #1540
+- Add compile-time opt-in to disable HIDE_REPRESENTATION for HTML types by @smoothdeveloper in #1499
+- Fix links in documentation by @kant2002 in #1597
+- Expand test coverage across CSV, JSON, HTML, XML, and WorldBank modules
 - Convert build.fsx script into a full build project at build/build.fsproj, letting developers use the .NET 6 runtime assem
... (truncated)

[dsyme]

applied manually