fix: preserve legacy EPUB namespace fallback

Author: ac1982

packages/markitdown/src/markitdown/converters/_epub_converter.py

@@ -161,18 +161,19 @@ def _resolve_manifest_href(
         return candidates[0]
 
     def _get_elements(
-        self, dom: Document, namespace: str, local_name: str
+        self,
+        dom: Document,
+        namespace: str,
+        local_name: str,
+        legacy_name: str | None = None,
     ) -> List[Element]:
         # Match namespace URIs, not the arbitrary prefix chosen by the author.
         nodes = list(dom.getElementsByTagNameNS(namespace, local_name))
         if nodes:
             return nodes
-        # Retain support for older files that omit the container/OPF namespace.
-        return [
-            node
-            for node in dom.getElementsByTagName(local_name)
-            if node.namespaceURI is None
-        ]
+        # Preserve the original tag-name lookup for legacy/malformed namespace
+        # URIs, but only when there are no elements in the standard namespace.
+        return list(dom.getElementsByTagName(legacy_name or local_name))
 
     def _get_text_from_node(self, dom: Document, tag_name: str) -> str | None:
         """Convenience function to extract a single occurrence of a tag (e.g., title)."""
@@ -185,7 +186,9 @@ def _get_text_from_node(self, dom: Document, tag_name: str) -> str | None:
     def _get_all_texts_from_nodes(self, dom: Document, tag_name: str) -> List[str]:
         """Helper function to extract all occurrences of a tag (e.g., multiple authors)."""
         texts: List[str] = []
-        for node in self._get_elements(dom, DC_NAMESPACE, tag_name.removeprefix("dc:")):
+        for node in self._get_elements(
+            dom, DC_NAMESPACE, tag_name.removeprefix("dc:"), legacy_name=tag_name
+        ):
             text_parts: List[str] = []
             self._collect_node_text(node, text_parts)
             text_val = "".join(text_parts).strip()

packages/markitdown/tests/test_epub.py

@@ -219,10 +219,6 @@ def test_epub_metadata_and_text_are_unchanged() -> None:
     assert "Chapter text." in result.markdown
 
 
-if __name__ == "__main__":
-    raise SystemExit(pytest.main([__file__]))
-
-
 @pytest.mark.parametrize("prefixed_part", ["container", "package", "metadata"])
 def test_namespace_prefixes_do_not_change_epub_conversion(prefixed_part):
     original = _build_epub(
@@ -276,3 +272,51 @@ def test_namespace_prefixes_do_not_change_epub_conversion(prefixed_part):
     text = result.markdown.replace("\\", "")
     assert "SECOND_BODY" in text and "FIRST_BODY" in text
     assert text.index("SECOND_BODY") < text.index("FIRST_BODY")
+
+
+@pytest.mark.parametrize(
+    "original_namespace,replacement_namespace",
+    [
+        (
+            "http://www.idpf.org/2007/opf",
+            "http://openebook.org/namespaces/oeb-package/1.0/",
+        ),
+        ("http://purl.org/dc/elements/1.1/", "http://purl.org/dc/elements/1.0/"),
+        ("http://purl.org/dc/elements/1.1/", "http://purl.org/dc/elements/1.1"),
+        ("urn:oasis:names:tc:opendocument:xmlns:container", "urn:legacy:container"),
+        ("urn:oasis:names:tc:opendocument:xmlns:container", ""),
+        ("http://www.idpf.org/2007/opf", ""),
+    ],
+)
+def test_legacy_namespace_uris_keep_metadata_and_chapters(
+    original_namespace, replacement_namespace
+):
+    original = _build_epub(
+        [("c1", "one.xhtml")],
+        ["c1"],
+        {"OEBPS/one.xhtml": ("First", "CHAPTER_BODY")},
+    )
+    archive = io.BytesIO()
+    with zipfile.ZipFile(original) as source, zipfile.ZipFile(archive, "w") as target:
+        for entry in source.infolist():
+            content = source.read(entry)
+            if entry.filename in ("META-INF/container.xml", "OEBPS/content.opf"):
+                text = content.decode().replace(
+                    original_namespace, replacement_namespace
+                )
+                if entry.filename == "OEBPS/content.opf":
+                    text = text.replace(
+                        "</metadata>",
+                        "<dc:creator>Example Author</dc:creator></metadata>",
+                    )
+                content = text.encode()
+            target.writestr(entry, content)
+    archive.seek(0)
+    result = EpubConverter().convert(archive, StreamInfo(extension=".epub"))
+    assert result.title == "Encoded Hrefs"
+    assert "**Authors:** Example Author" in result.markdown
+    assert "CHAPTER_BODY" in result.markdown.replace("\\", "")
+
+
+if __name__ == "__main__":
+    raise SystemExit(pytest.main([__file__]))