Fix Issue when rendering multi-line list items

src/Renderer/Block/ListBlockRenderer.php

@@ -26,6 +26,8 @@ public function render(Node $node, ChildNodeRendererInterface $childRenderer): s
         $content = $childRenderer->renderNodes($node->children());
         $content = explode("\n", $content);
 
+        $content = array_map(fn ($item) => $this->replaceInternalLineBreakCharacter($item), $content);
+
         if ($listData->type === ListBlock::TYPE_BULLET) {
             $content = array_map(fn ($item) => "- {$item}", $content);
         }
@@ -42,4 +44,16 @@ public function render(Node $node, ChildNodeRendererInterface $childRenderer): s
 
         return implode("\n", $content) . "\n";
     }
+
+    /**
+     * Replace custom line break character with _native_ line breaks.
+     * Whitespace is added so that other Markdown clients correctly
+     * render the list and its line breaks.
+     * @param string $content
+     * @return string
+     */
+    private function replaceInternalLineBreakCharacter(string $content): string
+    {
+        return str_replace(ListItemRenderer::INLINE_LINE_BREAK, "   \n  ", $content);
+    }
 }

src/Renderer/Block/ListItemRenderer.php

@@ -12,6 +12,8 @@
 
 final class ListItemRenderer implements \League\CommonMark\Renderer\NodeRendererInterface
 {
+    public const INLINE_LINE_BREAK = '_COMMONMARK_MARKDOWN_RENDERER_LINE_BREAK_';
+
     /**
      * @param ListItem $node
      *
@@ -24,6 +26,15 @@ public function render(Node $node, ChildNodeRendererInterface $childRenderer): s
         ListItem::assertInstanceOf($node);
 
         $contents = $childRenderer->renderNodes($node->children());
+
+        // If the ListItem contains a line break, replace the line break with a custom string.
+        // The custom line break string is being replaced with a _native_ line break again, when
+        // being rendered in a ListBlock.
+        // This workaround is required to support multi-line list items.
+        if (str_contains($contents, "\n")) {
+            $contents = str_replace("\n", self::INLINE_LINE_BREAK, $contents);
+        }
+
         if (str_starts_with($contents, '<') && ! $this->startsTaskListItem($node)) {
             $contents = "\n" . $contents;
         }

tests/Renderer/MarkdownRendererTest.php

@@ -41,11 +41,29 @@ public function it_renders_ast_to_markdown(): void
     public function it_parses_and_renders_kitchen_sink(): void
     {
         $contentKitchenSink = file_get_contents(__DIR__ . '/../stubs/kitchen-sink.md');
+        $contentKitchenSinkExpected = file_get_contents(__DIR__ . '/../stubs/kitchen-sink-expected.md');
 
         $document = $this->parser->parse($contentKitchenSink);
 
         $result = $this->renderer->renderDocument($document)->getContent();
 
-        $this->assertEquals($contentKitchenSink, $result);
+        $this->assertEquals($contentKitchenSinkExpected, $result);
+    }
+
+    #[Test]
+    public function it_parses_kitchen_sink_and_parsing_the_result_again_returns_the_same_result(): void
+    {
+        $contentKitchenSink = file_get_contents(__DIR__ . '/../stubs/kitchen-sink.md');
+        $contentKitchenSinkExpected = file_get_contents(__DIR__ . '/../stubs/kitchen-sink-expected.md');
+
+        $document = $this->parser->parse($contentKitchenSink);
+
+        $result = $this->renderer->renderDocument($document)->getContent();
+        $this->assertEquals($contentKitchenSinkExpected, $result);
+
+        // Take the result and parse it again
+        $document = $this->parser->parse($result);
+        $result = $this->renderer->renderDocument($document)->getContent();
+        $this->assertEquals($contentKitchenSinkExpected, $result);
     }
 }

tests/stubs/kitchen-sink-expected.md

@@ -0,0 +1,27 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
+
+## Curiosities
+
+- This is a list item which is followed by an indented content on the next line   
+  which is part of the same list item
+- This is a list item which contains multiple paragraphs   
+  This is the second paragraph.   
+  This is the third paragraph.
+- This is a list item with multiple paragraphs, but without trailing whitespace in the original document at the end   
+  This is the second paragraph.   
+  This is the third paragraph.
+
+## Task List
+
+- [ ] Task 1
+- [x] Task 2
+
+## [Unreleased](https://github.com/olivierlacan/keep-a-changelog/compare/v1.0.0...HEAD)
+
+**This Text is Bold**
+*This Text is Italic*
+
+`\Class->getFoo()`

tests/stubs/kitchen-sink.md

@@ -1,9 +1,18 @@
 # Changelog
 
 All notable changes to this project will be documented in this file.
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
-The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
-and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+## Curiosities
+
+- This is a list item which is followed by an indented content on the next line   
+  which is part of the same list item
+- This is a list item which contains multiple paragraphs   
+  This is the second paragraph.   
+  This is the third paragraph.
+- This is a list item with multiple paragraphs, but without trailing whitespace in the original document at the end
+  This is the second paragraph.
+  This is the third paragraph.
 
 ## Task List
 
@@ -12,165 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/olivierlacan/keep-a-changelog/compare/v1.0.0...HEAD)
 
-## [1.0.0](https://github.com/olivierlacan/keep-a-changelog/compare/v0.3.0...v1.0.0) - 2017-06-20
-
-### Added
-
-- New visual identity by [@tylerfortune8](https://github.com/tylerfortune8).
-- Version navigation.
-- Links to latest released version in previous versions.
-- "Why keep a changelog?" section.
-- "Who needs a changelog?" section.
-- "How do I make a changelog?" section.
-- "Frequently Asked Questions" section.
-- New "Guiding Principles" sub-section to "How do I make a changelog?".
-- Simplified and Traditional Chinese translations from [@tianshuo](https://github.com/tianshuo).
-- German translation from [@mpbzh](https://github.com/mpbzh) & [@Art4](https://github.com/Art4).
-- Italian translation from [@azkidenz](https://github.com/azkidenz).
-- Swedish translation from [@magol](https://github.com/magol).
-- Turkish translation from [@karalamalar](https://github.com/karalamalar).
-- French translation from [@zapashcanon](https://github.com/zapashcanon).
-- Brazilian Portugese translation from [@Webysther](https://github.com/Webysther).
-- Polish translation from [@amielucha](https://github.com/amielucha) & [@m-aciek](https://github.com/m-aciek).
-- Russian translation from [@aishek](https://github.com/aishek).
-- Czech translation from [@h4vry](https://github.com/h4vry).
-- Slovak translation from [@jkostolansky](https://github.com/jkostolansky).
-- Korean translation from [@pierceh89](https://github.com/pierceh89).
-- Croatian translation from [@porx](https://github.com/porx).
-- Persian translation from [@Hameds](https://github.com/Hameds).
-- Ukrainian translation from [@osadchyi-s](https://github.com/osadchyi-s).
-
-### Changed
-
-- Start using "changelog" over "change log" since it's the common usage.
-- Start versioning based on the current English version at 0.3.0 to help
-- translation authors keep things up-to-date.
-- Rewrite "What makes unicorns cry?" section.
-- Rewrite "Ignoring Deprecations" sub-section to clarify the ideal
-- scenario.
-- Improve "Commit log diffs" sub-section to further argument against
-- them.
-- Merge "Why can’t people just use a git log diff?" with "Commit log
-- diffs"
-- Fix typos in Simplified Chinese and Traditional Chinese translations.
-- Fix typos in Brazilian Portuguese translation.
-- Fix typos in Turkish translation.
-- Fix typos in Czech translation.
-- Fix typos in Swedish translation.
-- Improve phrasing in French translation.
-- Fix phrasing and spelling in German translation.
-
-### Removed
-
-- Section about "changelog" vs "CHANGELOG".
-
-## [0.3.0](https://github.com/olivierlacan/keep-a-changelog/compare/v0.2.0...v0.3.0) - 2015-12-03
-
-### Added
-
-- RU translation from [@aishek](https://github.com/aishek).
-- pt-BR translation from [@tallesl](https://github.com/tallesl).
-- es-ES translation from [@ZeliosAriex](https://github.com/ZeliosAriex).
-
-## [0.2.0](https://github.com/olivierlacan/keep-a-changelog/compare/v0.1.0...v0.2.0) - 2015-10-06
-
-### Changed
-
-- Remove exclusionary mentions of "open source" since this project can
-- benefit both "open" and "closed" source projects equally.
-
-## [0.1.0](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.8...v0.1.0) - 2015-10-06
-
-### Added
-
-- Answer "Should you ever rewrite a change log?".
-
-### Changed
-
-- Improve argument against commit logs.
-- Start following [SemVer](https://semver.org) properly.
-
-## [0.0.8](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.7...v0.0.8) - 2015-02-17
-
-### Changed
-
-- Update year to match in every README example.
-- Reluctantly stop making fun of Brits only, since most of the world
-- writes dates in a strange way.
-
-### Fixed
-
-- Fix typos in recent README changes.
-- Update outdated unreleased diff link.
-
-## [0.0.7](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.6...v0.0.7) - 2015-02-16
-
-### Added
-
-- Link, and make it obvious that date format is ISO 8601.
-
-### Changed
-
-- Clarified the section on "Is there a standard change log format?".
-
-### Fixed
-
-- Fix Markdown links to tag comparison URL with footnote-style links.
-
-## [0.0.6](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.5...v0.0.6) - 2014-12-12
-
-### Added
-
-- README section on "yanked" releases.
-
-## [0.0.5](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.4...v0.0.5) - 2014-08-09
-
-### Added
-
-- Markdown links to version tags on release headings.
-- Unreleased section to gather unreleased changes and encourage note
-- keeping prior to releases.
-
-## [0.0.4](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.3...v0.0.4) - 2014-08-09
-
-### Added
-
-- Better explanation of the difference between the file ("CHANGELOG")
-- and its function "the change log".
-
-### Changed
-
-- Refer to a "change log" instead of a "CHANGELOG" throughout the site
-- to differentiate between the file and the purpose of the file — the
-- logging of changes.
-
-### Removed
-
-- Remove empty sections from CHANGELOG, they occupy too much space and
-- create too much noise in the file. People will have to assume that the
-- missing sections were intentionally left out because they contained no
-- notable changes.
-
-## [0.0.3](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.2...v0.0.3) - 2014-08-09
-
-### Added
-
-- "Why should I care?" section mentioning The Changelog podcast.
-
-## [0.0.2](https://github.com/olivierlacan/keep-a-changelog/compare/v0.0.1...v0.0.2) - 2014-07-10
-
-### Added
-
-- Explanation of the recommended reverse chronological release ordering.
-
-## [0.0.1](https://github.com/olivierlacan/keep-a-changelog/releases/tag/v0.0.1) - 2014-05-31
-
-### Added
+**This Text is Bold**
+*This Text is Italic*
 
-- This CHANGELOG file to hopefully serve as an evolving example of a
-- standardized open source project CHANGELOG.
-- CNAME file to enable GitHub Pages custom domain
-- README now contains answers to common questions about CHANGELOGs
-- Good examples and basic guidelines, including proper date formatting.
-- Counter-examples: "What makes unicorns cry?"
-- `\Class->getFoo()`
+`\Class->getFoo()`