fix(file-summary): 避免无效 Office 文件触发 COM 统计

tests/test_file_summary_page_count.py

@@ -77,6 +77,10 @@ def test_count_docx_pages_uses_word_com_fallback(monkeypatch, tmp_path):
 def test_count_doc_pages_uses_word_com_fallback(monkeypatch, tmp_path):
     doc_path = tmp_path / "legacy.doc"
     doc_path.write_bytes(b"legacy-doc-placeholder")
+    monkeypatch.setattr(
+        "review_agent.file_summary.services.page_count._can_try_com_fallback",
+        lambda path, ext: True,
+    )
     monkeypatch.setattr(
         "review_agent.file_summary.services.page_count._count_word_pages_with_com",
         lambda path: 5,
@@ -91,6 +95,10 @@ def test_count_doc_pages_uses_word_com_fallback(monkeypatch, tmp_path):
 def test_count_ppt_pages_uses_powerpoint_com_fallback(monkeypatch, tmp_path):
     ppt_path = tmp_path / "legacy.ppt"
     ppt_path.write_bytes(b"legacy-ppt-placeholder")
+    monkeypatch.setattr(
+        "review_agent.file_summary.services.page_count._can_try_com_fallback",
+        lambda path, ext: True,
+    )
     monkeypatch.setattr(
         "review_agent.file_summary.services.page_count._count_powerpoint_slides_with_com",
         lambda path: 9,
@@ -105,6 +113,10 @@ def test_count_ppt_pages_uses_powerpoint_com_fallback(monkeypatch, tmp_path):
 def test_count_excel_pages_uses_excel_com_fallback(monkeypatch, tmp_path):
     xls_path = tmp_path / "legacy.xls"
     xls_path.write_bytes(b"legacy-xls-placeholder")
+    monkeypatch.setattr(
+        "review_agent.file_summary.services.page_count._can_try_com_fallback",
+        lambda path, ext: True,
+    )
     monkeypatch.setattr(
         "review_agent.file_summary.services.page_count._count_excel_sheets_with_com",
         lambda path: 3,
@@ -116,6 +128,23 @@ def test_count_excel_pages_uses_excel_com_fallback(monkeypatch, tmp_path):
     assert result.page_count == 3
 
 
+def test_invalid_xlsx_does_not_start_excel_com(monkeypatch, tmp_path):
+    xlsx_path = tmp_path / "broken.xlsx"
+    xlsx_path.write_bytes(b"not a real workbook")
+
+    def fail_if_called(path):
+        raise AssertionError("Excel COM should not start for invalid xlsx signatures")
+
+    monkeypatch.setattr(
+        "review_agent.file_summary.services.page_count._count_excel_sheets_with_com",
+        fail_if_called,
+    )
+
+    result = count_document_pages(xlsx_path)
+
+    assert result.status == "uncertain"
+
+
 def test_document_page_count_skill_marks_unsupported_and_success(tmp_path, django_user_model):
     xlsx_path = tmp_path / "a.xlsx"
     workbook = Workbook()