From 521a1b3962ae3688f2c4ac49e4ae42391ccdf458 Mon Sep 17 00:00:00 2001
From: Parker Lougheed <parlough@gmail.com>
Date: Thu, 26 Oct 2023 09:10:37 -0500
Subject: [PATCH] Account for nested markdown code blocks in code excerpt tool
 (#195)

---
 .gitignore                                    |  5 +++--
 .../lib/src/code_excerpt_updater.dart         | 21 ++++++++++++++-----
 .../code_excerpt_updater/test/main_test.dart  |  2 ++
 .../test_data/expected/dartdoc.md             | 12 +++++++++++
 .../test_data/src/dartdoc.md                  |  8 +++++++
 .../test_data/src/no_change/dartdoc.md        | 12 +++++++++++
 6 files changed, 53 insertions(+), 7 deletions(-)
 create mode 100644 packages/code_excerpt_updater/test_data/expected/dartdoc.md
 create mode 100644 packages/code_excerpt_updater/test_data/src/dartdoc.md
 create mode 100644 packages/code_excerpt_updater/test_data/src/no_change/dartdoc.md

diff --git a/.gitignore b/.gitignore
index 4d0bcc7..6b96cac 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,8 +1,9 @@
 *.iml
 .idea
 .vscode
+.DS_Store
 
-.packages
-.pub
+.dart_tool
+build/
 
 build
diff --git a/packages/code_excerpt_updater/lib/src/code_excerpt_updater.dart b/packages/code_excerpt_updater/lib/src/code_excerpt_updater.dart
index 3860dd1..68ab77e 100644
--- a/packages/code_excerpt_updater/lib/src/code_excerpt_updater.dart
+++ b/packages/code_excerpt_updater/lib/src/code_excerpt_updater.dart
@@ -27,8 +27,7 @@ import 'logger.dart';
 /// [fragmentDirPath] directory, and diff sources from `srcDirPath`.
 class Updater {
   static final RegExp codeBlockStartMarker =
-      RegExp(r'^\s*(///?)?\s*(```|{%-?\s*\w+\s*(\w*)(\s+.*)?-?%})?');
-  static final RegExp codeBlockEndMarker = RegExp(r'^\s*(///?)?\s*(```)?');
+      RegExp(r'^\s*(///?)?\s*(```+|{%-?\s*\w+\s*(\w*)(\s+.*)?-?%})?');
   static final RegExp codeBlockEndPrettifyMarker =
       RegExp(r'^\s*(///?)?\s*({%-?\s*end\w+\s*-?%})?');
 
@@ -217,9 +216,18 @@ class Updater {
       return <String>[openingCodeBlockLine];
     }
 
-    final codeBlockEndChecker = firstLineMatch[2]?.startsWith('`') == true
-        ? codeBlockEndMarker
-        : codeBlockEndPrettifyMarker;
+    final RegExp codeBlockEndChecker;
+    final codeBlockStart = firstLineMatch[2];
+    if (codeBlockStart != null && codeBlockStart.startsWith('`')) {
+      // Create a RegExp to check for at least the same amount of backticks
+      // as the opening backticks had.
+      final backtickCount = codeBlockStart.length;
+      codeBlockEndChecker = _createCodeBlockEndMarker(backtickCount);
+    } else {
+      // Fall back to the prettify end marker for now.
+      codeBlockEndChecker = codeBlockEndPrettifyMarker;
+    }
+
     String? closingCodeBlockLine;
     while (_lines.isNotEmpty) {
       line = _lines[0];
@@ -350,4 +358,7 @@ class Updater {
     if (ext.startsWith('.')) ext = ext.substring(1);
     return ext;
   }
+
+  static RegExp _createCodeBlockEndMarker(int backtickCount) =>
+      RegExp(r'^\s*(///?)?\s*' '(`{$backtickCount})?');
 }
diff --git a/packages/code_excerpt_updater/test/main_test.dart b/packages/code_excerpt_updater/test/main_test.dart
index 0212e51..6f25f52 100644
--- a/packages/code_excerpt_updater/test/main_test.dart
+++ b/packages/code_excerpt_updater/test/main_test.dart
@@ -131,6 +131,7 @@ void testsFromDefaultDir() {
       'basic_no_region.dart',
       'basic_with_args.md',
       'basic_with_region.dart',
+      'dartdoc.md',
       'diff.md',
       'frag_not_found.dart',
       'invalid_code_block.dart',
@@ -152,6 +153,7 @@ void testsFromDefaultDir() {
       'basic_no_region.dart',
       'basic_with_empty_region.md',
       'basic_with_region.dart',
+      'dartdoc.md',
       'escape_ng_interpolation.md',
       'fragment-indentation.md',
       'language-tour.md',
diff --git a/packages/code_excerpt_updater/test_data/expected/dartdoc.md b/packages/code_excerpt_updater/test_data/expected/dartdoc.md
new file mode 100644
index 0000000..5c08223
--- /dev/null
+++ b/packages/code_excerpt_updater/test_data/expected/dartdoc.md
@@ -0,0 +1,12 @@
+## API docs
+
+Markdown code block opened and closed with more than 3 backticks
+that contains another Markdown code block declared with just 3.
+
+<?code-excerpt "backticks_in_api_doc.dart"?>
+````dart
+/// ```html
+/// <h1>HTML is magical!</h1>
+/// ```
+class HTML {}
+````
diff --git a/packages/code_excerpt_updater/test_data/src/dartdoc.md b/packages/code_excerpt_updater/test_data/src/dartdoc.md
new file mode 100644
index 0000000..6b85d49
--- /dev/null
+++ b/packages/code_excerpt_updater/test_data/src/dartdoc.md
@@ -0,0 +1,8 @@
+## API docs
+
+Markdown code block opened and closed with more than 3 backticks
+that contains another Markdown code block declared with just 3.
+
+<?code-excerpt "backticks_in_api_doc.dart"?>
+````dart
+````
diff --git a/packages/code_excerpt_updater/test_data/src/no_change/dartdoc.md b/packages/code_excerpt_updater/test_data/src/no_change/dartdoc.md
new file mode 100644
index 0000000..5c08223
--- /dev/null
+++ b/packages/code_excerpt_updater/test_data/src/no_change/dartdoc.md
@@ -0,0 +1,12 @@
+## API docs
+
+Markdown code block opened and closed with more than 3 backticks
+that contains another Markdown code block declared with just 3.
+
+<?code-excerpt "backticks_in_api_doc.dart"?>
+````dart
+/// ```html
+/// <h1>HTML is magical!</h1>
+/// ```
+class HTML {}
+````