From 61b45712d8f01c79fc28207292d492b15884d8b5 Mon Sep 17 00:00:00 2001
From: Isaac Muse <faceless.shop@gmail.com>
Date: Tue, 4 Apr 2023 17:02:10 -0600
Subject: [PATCH] Ignore nested snippet sections (#2003)

---
 docs/src/markdown/about/changelog.md          |  4 ++
 pymdownx/snippets.py                          | 26 ++++++--
 .../_snippets/section_nested.txt              | 29 +++++++++
 tests/test_extensions/test_snippets.py        | 62 +++++++++++++++++++
 4 files changed, 117 insertions(+), 4 deletions(-)
 create mode 100644 tests/test_extensions/_snippets/section_nested.txt

diff --git a/docs/src/markdown/about/changelog.md b/docs/src/markdown/about/changelog.md
index 9ec0da4ef..350c39402 100644
--- a/docs/src/markdown/about/changelog.md
+++ b/docs/src/markdown/about/changelog.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 9.11
+
+- **NEW**: Snippets: Ignore nested snippet section syntax when including a section.
+
 ## 9.10
 
 - **NEW**: Blocks: Add new experimental general purpose blocks that provide a framework for creating fenced block
diff --git a/pymdownx/snippets.py b/pymdownx/snippets.py
index 44318160f..e7ae2e986 100644
--- a/pymdownx/snippets.py
+++ b/pymdownx/snippets.py
@@ -66,10 +66,11 @@ class SnippetPreprocessor(Preprocessor):
 
     RE_SNIPPET_SECTION = re.compile(
         r'''(?xi)
-        ^.*?
+        ^(?P<pre>.*?)
+        (?P<escape>;*)
         (?P<inline_marker>-{1,}8<-{1,}[ \t]+)
-        \[[ \t]*(?P<type>start|end)[ \t]*:[ \t]*(?P<name>[a-z][-_0-9a-z]*)[ \t]*\]
-        .*?$
+        (?P<section>\[[ \t]*(?P<type>start|end)[ \t]*:[ \t]*(?P<name>[a-z][-_0-9a-z]*)[ \t]*\])
+        (?P<post>.*?)$
         '''
     )
 
@@ -103,7 +104,16 @@ def extract_section(self, section, lines):
 
             # Found a snippet section marker with our specified name
             m = self.RE_SNIPPET_SECTION.match(l)
-            if m is not None and m.group('name') == section:
+
+            # Handle escaped line
+            if m and start and m.group('escape'):
+                l = (
+                    m.group('pre') + m.group('escape').replace(';', '', 1) + m.group('inline_marker') +
+                    m.group('section') + m.group('post')
+                )
+
+            # Found a section we are looking for.
+            elif m is not None and m.group('name') == section:
 
                 # We found the start
                 if not start and m.group('type') == 'start':
@@ -111,6 +121,10 @@ def extract_section(self, section, lines):
                     found = True
                     continue
 
+                # Ignore duplicate start
+                elif start and m.group('type') == 'start':
+                    continue
+
                 # We found the end
                 elif start and m.group('type') == 'end':
                     start = False
@@ -120,6 +134,10 @@ def extract_section(self, section, lines):
                 else:
                     break
 
+            # Found a section we don't care about, so ignore it.
+            elif m and start:
+                continue
+
             # We are currently in a section, so append the line
             if start:
                 new_lines.append(l)
diff --git a/tests/test_extensions/_snippets/section_nested.txt b/tests/test_extensions/_snippets/section_nested.txt
new file mode 100644
index 000000000..cdc7cc54c
--- /dev/null
+++ b/tests/test_extensions/_snippets/section_nested.txt
@@ -0,0 +1,29 @@
+/* --8<-- [start: css-section] */
+div {
+    color: red;
+    /* --8<-- [start: css-section2] */
+    background-color: white;
+    padding: 16px
+    /* --8<-- [end: css-section2] */
+}
+/* --8<-- [end: css-section] */
+
+
+/* --8<-- [start: css-section3] */
+div {
+    color: red;
+    /* ;--8<-- [start: css-section4] */
+    background-color: white;
+    padding: 16px
+    /* ;--8<-- [end: css-section4] */
+}
+/* --8<-- [end: css-section3] */
+
+/* --8<-- [start: css-section5] */
+div {
+    color: red;
+    /* --8<-- [start: css-section5] */
+    background-color: white;
+    padding: 16px
+}
+/* --8<-- [end: css-section5] */
diff --git a/tests/test_extensions/test_snippets.py b/tests/test_extensions/test_snippets.py
index 310060206..e91a8c4de 100644
--- a/tests/test_extensions/test_snippets.py
+++ b/tests/test_extensions/test_snippets.py
@@ -332,6 +332,68 @@ def test_section_inline_min(self):
             True
         )
 
+    def test_section_inline_ignore_other_section(self):
+        """Test nested sections."""
+
+        self.check_markdown(
+            R'''
+            ```
+            -8<- "section_nested.txt:css-section"
+            ```
+            ''',
+            '''
+            <div class="highlight"><pre><span></span><code>div {
+                color: red;
+                background-color: white;
+                padding: 16px
+            }
+            </code></pre></div>
+            ''',
+            True
+        )
+
+    def test_section_inline_escaped_other_section(self):
+        """Test nested escaped sections."""
+
+        self.check_markdown(
+            R'''
+            ```
+            -8<- "section_nested.txt:css-section3"
+            ```
+            ''',
+            '''
+            <div class="highlight"><pre><span></span><code>div {
+                color: red;
+                /* --8&lt;-- [start: css-section4] */
+                background-color: white;
+                padding: 16px
+                /* --8&lt;-- [end: css-section4] */
+            }
+            </code></pre></div>
+            ''',
+            True
+        )
+
+    def test_section_ignore_double_start_section(self):
+        """Test nested sections."""
+
+        self.check_markdown(
+            R'''
+            ```
+            -8<- "section_nested.txt:css-section5"
+            ```
+            ''',
+            '''
+            <div class="highlight"><pre><span></span><code>div {
+                color: red;
+                background-color: white;
+                padding: 16px
+            }
+            </code></pre></div>
+            ''',
+            True
+        )
+
     def test_section_block(self):
         """Test section partial in block snippet."""