🔖 Prepare release v4.0.0

⚡️ A message from a fellow meat-based-AI ⚡️
- [❤️] Finely-crafted open-source tools like ast-merge (& many more) require time and effort.
- [❤️] Though I adore my work, it lacks financial sustainability.
- [❤️] Please, help me continue enhancing your tools by becoming a sponsor:
  - [💲] https://liberapay.com/pboling/donate
  - [💲] https://github.com/sponsors/pboling

Author: pboling

CHANGELOG.md

@@ -20,6 +20,25 @@ Please file a bug if you notice a violation of semantic versioning.
 
 ### Added
 
+### Changed
+
+### Deprecated
+
+### Removed
+
+### Fixed
+
+### Security
+
+## [4.0.0] - 2026-01-11
+
+- TAG: [v4.0.0][4.0.0t]
+- COVERAGE: 96.52% -- 2555/2647 lines in 51 files
+- BRANCH COVERAGE: 87.62% -- 814/929 branches in 51 files
+- 98.80% documented
+
+### Added
+
 - `Recipe::Preset#normalize_whitespace` - option to collapse excessive blank lines in merged output
 - `Recipe::Preset#rehydrate_link_references` - option to convert inline links to reference style
 - `Recipe::Runner::Result#problems` - access document problems found during merge
@@ -70,17 +89,11 @@ Please file a bug if you notice a violation of semantic versioning.
   - Reports duplicate link definitions, link ref spacing fixes, and other problems from `MergeResult#problems`
   - Removed custom regex-based link rehydration and whitespace normalization
 
-### Deprecated
-
-### Removed
-
 ### Fixed
 
 - `Ast::Merge::PartialTemplateMergerBase#normalize_matcher` now preserves `same_or_shallower` key from boundary config
 - `Ast::Merge::PartialTemplateMergerBase#merge` now passes `boundary_same_or_shallower` to `InjectionPointFinder#find`
 
-### Security
-
 ## [3.1.0] - 2026-01-08
 
 - TAG: [v3.1.0][3.1.0t]
@@ -584,7 +597,9 @@ Please file a bug if you notice a violation of semantic versioning.
 
 - Initial release
 
-[Unreleased]: https://github.com/kettle-rb/ast-merge/compare/v3.1.0...HEAD
+[Unreleased]: https://github.com/kettle-rb/ast-merge/compare/v4.0.0...HEAD
+[4.0.0]: https://github.com/kettle-rb/ast-merge/compare/v3.1.0...v4.0.0
+[4.0.0t]: https://github.com/kettle-rb/ast-merge/releases/tag/v4.0.0
 [3.1.0]: https://github.com/kettle-rb/ast-merge/compare/v3.0.0...v3.1.0
 [3.1.0t]: https://github.com/kettle-rb/ast-merge/releases/tag/v3.1.0
 [3.0.0]: https://github.com/kettle-rb/ast-merge/compare/v2.0.10...v3.0.0

Gemfile.lock

@@ -30,7 +30,7 @@ GIT
 PATH
   remote: .
   specs:
-    ast-merge (3.1.0)
+    ast-merge (4.0.0)
       tree_haver (~> 5.0, >= 5.0.0)
       version_gem (~> 1.1, >= 1.1.9)
 
@@ -413,7 +413,7 @@ CHECKSUMS
   ansi (1.5.0) sha256=5408253274e33d9d27d4a98c46d2998266fd51cba58a7eb9d08f50e57ed23592
   appraisal2 (3.0.0) sha256=f1b4e742cf8ebef5e9fbb76c416a8c16edfe0727964a5a17b44adfc37b701aed
   ast (2.4.3) sha256=954615157c1d6a382bc27d690d973195e79db7f55e9765ac7c481c60bdb4d383
-  ast-merge (3.1.0)
+  ast-merge (4.0.0)
   backports (3.25.3) sha256=94298d32dc3c40ca15633b54e282780b49e2db0c045f602ea1907e4f63a17235
   benchmark (0.5.0) sha256=465df122341aedcb81a2a24b4d3bd19b6c67c1530713fd533f3ff034e419236c
   bigdecimal (3.3.1) sha256=eaa01e228be54c4f9f53bf3cc34fe3d5e845c31963e7fcc5bedb05a4e7d52218

README.md

@@ -1108,7 +1108,7 @@ Thanks for RTFM. ☺️
 [📌gitmoji]: https://gitmoji.dev
 [📌gitmoji-img]: https://img.shields.io/badge/gitmoji_commits-%20%F0%9F%98%9C%20%F0%9F%98%8D-34495e.svg?style=flat-square
 [🧮kloc]: https://www.youtube.com/watch?v=dQw4w9WgXcQ
-[🧮kloc-img]: https://img.shields.io/badge/KLOC-2.544-FFDD67.svg?style=for-the-badge&logo=YouTube&logoColor=blue
+[🧮kloc-img]: https://img.shields.io/badge/KLOC-2.647-FFDD67.svg?style=for-the-badge&logo=YouTube&logoColor=blue
 [🔐security]: SECURITY.md
 [🔐security-img]: https://img.shields.io/badge/security-policy-259D6C.svg?style=flat
 [📄copyright-notice-explainer]: https://opensource.stackexchange.com/questions/5778/why-do-licenses-such-as-the-mit-license-specify-a-single-year

docs/Ast.html

@@ -191,7 +191,7 @@ <h5 class="example_title"><div class='inline'><p>Usage in specs</p>
 </div>
 
       <div id="footer">
-  Generated on Sun Jan 11 04:45:14 2026 by
+  Generated on Sun Jan 11 04:56:55 2026 by
   <a href="https://yardoc.org" title="Yay! A Ruby Documentation Tool" target="_parent">yard</a>
   0.9.38 (ruby-4.0.0).
 </div>

docs/Ast/Merge.html

@@ -158,7 +158,7 @@ <h2>
 </div>
 
       <div id="footer">
-  Generated on Sun Jan 11 04:45:14 2026 by
+  Generated on Sun Jan 11 04:56:55 2026 by
   <a href="https://yardoc.org" title="Yay! A Ruby Documentation Tool" target="_parent">yard</a>
   0.9.38 (ruby-4.0.0).
 </div>