fix: Sprungziel für Notenverweise aus HTML-Tabellen bei GFM-Fußnoten (QA2-03)

Wird dieselbe Anmerkung aus einer als HTML erhaltenen Tabelle und aus
dem Fließtext referenziert, entstand nur eine [^fn-…]-Definition; der
HTML-Verweis <a href="#fn-…"> lief ins Leere. Die Definition erhält in
diesem Fall zusätzlich den Anker <a id="fn-…">.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

epub2md/html_converter.py

@@ -936,6 +936,9 @@ class Renderer:
             blocks = self.render_note(note) or ["(leer)"]
             body = "\n\n".join(blocks)
             if note.label in self.md_ref_labels:
+                if f"{self.file}:{note.label}" in self.note_refs:
+                    # also referenced from an HTML table (<a href="#fn-…">): give that link a target
+                    body = f'<a id="{note.label}"></a>' + body
                 out.append(indent_block(body, f"[^{note.label}]: ", "    "))
             else:
                 num = int(note.label.split("-")[1])

tests/test_qa_regressions.py

@@ -59,3 +59,18 @@ def test_backlink_after_code_block_does_not_break_fence_end_of_book(convert):
     assert _fences_closed(notes), notes
     assert not re.search(r"\*\*\d+[:.]\*\* ```", notes), "Fence hinter Notennummer ist kein Codeblock"
     assert "[↩](001-k.md#fnref-001)" in notes
+
+
+NOTE_IN_HTML_TABLE = ('<h1>K</h1><table><tr><td colspan="2">Zelle<a epub:type="noteref" href="#n1" id="r1">1</a></td></tr>'
+                      "<tr><td>a</td><td>b</td></tr></table>"
+                      '<p>Text<a epub:type="noteref" href="#n1" id="r1b">1</a>.</p>'
+                      '<aside epub:type="footnote" id="n1"><p>Die Note.</p></aside>')
+
+
+def test_note_referenced_from_html_table_and_text_has_target(convert):
+    """QA2-03: GFM: the HTML-table reference pointed to #fn-001, but only a [^fn-001] definition existed."""
+    run = convert(Book(docs=[Doc("c.xhtml", NOTE_IN_HTML_TABLE)]))
+    text = run.chapter("001")
+    assert 'href="#fn-001"' in text and "Text[^fn-001]." in text
+    assert re.search(r'id="fn-001"', text), text
+    assert run.report["output_link_check"]["broken_count"] == 0