fix(markdown): retain nested preserved HTML tags

crawl4ai/html2text/__init__.py

@@ -1119,17 +1119,17 @@ def handle_tag(self, tag, attrs, start):
                 if self.preserve_depth == 0:
                     self.current_preserved_tag = tag
                     self.preserved_content = []
-                    # Format opening tag with attributes
-                    attr_str = "".join(
-                        f' {k}="{v}"' for k, v in attrs.items() if v is not None
-                    )
-                    self.preserved_content.append(f"<{tag}{attr_str}>")
+                # Record nested preserved tags as well as the outer block.
+                attr_str = "".join(
+                    f' {k}="{v}"' for k, v in attrs.items() if v is not None
+                )
+                self.preserved_content.append(f"<{tag}{attr_str}>")
                 self.preserve_depth += 1
                 return
             else:
+                self.preserved_content.append(f"</{tag}>")
                 self.preserve_depth -= 1
                 if self.preserve_depth == 0:
-                    self.preserved_content.append(f"</{tag}>")
                     # Output the preserved HTML block with proper spacing
                     preserved_html = "".join(self.preserved_content)
                     self.o("\n" + preserved_html + "\n")

tests/unit/test_markdown_preserved_tags.py

@@ -0,0 +1,46 @@
+"""Regression tests for nested tags preserved during Markdown generation."""
+
+import pytest
+
+from crawl4ai import DefaultMarkdownGenerator
+
+
+@pytest.mark.parametrize(
+    ("html", "preserve_tags"),
+    [
+        (
+            '<div class="outer">outer<div class="inner">inner</div>end</div>',
+            ["div"],
+        ),
+        (
+            '<section id="outer">outer<div id="inner">inner</div>end</section>',
+            ["section", "div"],
+        ),
+        (
+            "<table><tr><td>outer<table><tr><td>inner</td></tr></table>"
+            "end</td></tr></table>",
+            ["table"],
+        ),
+        (
+            '<div id="outer"><div id="middle"><div id="inner">'
+            "content</div></div></div>",
+            ["div"],
+        ),
+        (
+            '<div class="outer">outer<span class="inner">inner</span>end</div>',
+            ["div"],
+        ),
+        (
+            '<div id="first">one</div><div id="second">two</div>',
+            ["div"],
+        ),
+    ],
+    ids=["same-tag", "mixed-tags", "nested-table", "three-levels", "child", "siblings"],
+)
+def test_markdown_preserves_nested_html_tags(html, preserve_tags):
+    generator = DefaultMarkdownGenerator(options={"preserve_tags": preserve_tags})
+
+    result = generator.generate_markdown(html, citations=False)
+
+    # Preserved blocks gain separating newlines, but retain their HTML structure.
+    assert result.raw_markdown.strip().replace("\n", "") == html