Preserve percent-encoded octets in href paths

packages/markitdown/src/markitdown/converters/_markdownify.py

@@ -2,7 +2,24 @@
 import markdownify
 
 from typing import Any, Optional
-from urllib.parse import quote, unquote, urlparse, urlunparse
+from urllib.parse import quote, urlparse, urlunparse
+
+
+_PERCENT_ENCODED_OCTET = re.compile(r"%[0-9A-Fa-f]{2}")
+
+
+def _quote_path_preserving_percent_encoded_octets(path: str) -> str:
+    """Quote a URL path while preserving existing %HH byte encodings."""
+    parts: list[str] = []
+    last_end = 0
+
+    for match in _PERCENT_ENCODED_OCTET.finditer(path):
+        parts.append(quote(path[last_end : match.start()]))
+        parts.append(match.group(0))
+        last_end = match.end()
+
+    parts.append(quote(path[last_end:]))
+    return "".join(parts)
 
 
 class _CustomMarkdownify(markdownify.MarkdownConverter):
@@ -60,7 +77,13 @@ def convert_a(
                 parsed_url = urlparse(href)  # type: ignore
                 if parsed_url.scheme and parsed_url.scheme.lower() not in ["http", "https", "file"]:  # type: ignore
                     return "%s%s%s" % (prefix, text, suffix)
-                href = urlunparse(parsed_url._replace(path=quote(unquote(parsed_url.path))))  # type: ignore
+                href = urlunparse(
+                    parsed_url._replace(
+                        path=_quote_path_preserving_percent_encoded_octets(
+                            parsed_url.path
+                        )
+                    )
+                )  # type: ignore
             except ValueError:  # It's not clear if this ever gets thrown
                 return "%s%s%s" % (prefix, text, suffix)
 

packages/markitdown/tests/test_html_converter.py

@@ -0,0 +1,65 @@
+import io
+
+from markitdown import MarkItDown
+
+
+def _convert_html(html: str) -> str:
+    result = MarkItDown().convert_stream(
+        io.BytesIO(html.encode("utf-8")),
+        file_extension=".html",
+    )
+    return result.markdown
+
+
+def test_preserves_non_utf8_percent_encoded_href_path() -> None:
+    href = "https://abc.com/hist/" "%a5%c8%a5%c3%a5%d7%a5%da%a1%bc%a5%b8"
+    html = f'<a href="{href}">example</a>'
+
+    markdown = _convert_html(html)
+
+    assert f"[example]({href})" in markdown
+    assert "%EF%BF%BD" not in markdown
+
+
+def test_html_href_still_quotes_raw_unicode_and_spaces() -> None:
+    href = "https://example.com/a path/日本語"
+    expected_href = "https://example.com/a%20path/" "%E6%97%A5%E6%9C%AC%E8%AA%9E"
+
+    markdown = _convert_html(f'<a href="{href}">example</a>')
+
+    assert f"[example]({expected_href})" in markdown
+
+
+def test_html_href_quotes_literal_percent_sign() -> None:
+    href = "https://example.com/100% complete"
+    expected_href = "https://example.com/100%25%20complete"
+
+    markdown = _convert_html(f'<a href="{href}">example</a>')
+
+    assert f"[example]({expected_href})" in markdown
+
+
+def test_html_href_quotes_malformed_percent_escape() -> None:
+    href = "https://example.com/items/%ZZ/%2F"
+    expected_href = "https://example.com/items/%25ZZ/%2F"
+
+    markdown = _convert_html(f'<a href="{href}">example</a>')
+
+    assert f"[example]({expected_href})" in markdown
+
+
+def test_html_href_preserves_encoded_slash() -> None:
+    href = "https://example.com/items/a%2Fb"
+
+    markdown = _convert_html(f'<a href="{href}">example</a>')
+
+    assert f"[example]({href})" in markdown
+
+
+def test_html_href_does_not_quote_query_or_fragment() -> None:
+    href = "https://example.com/a path?query=a b%20c#fragment with spaces"
+    expected_href = "https://example.com/a%20path?query=a b%20c#fragment with spaces"
+
+    markdown = _convert_html(f'<a href="{href}">example</a>')
+
+    assert f"[example]({expected_href})" in markdown