ROB: Allow more whitespaces within linearized file (#1701)

Closes #1689

Author: pubpub-zz

pypdf/_reader.py

@@ -1801,7 +1801,7 @@ def _read_xref_other_error(
             return startxref
         # No explicit xref table, try finding a cross-reference stream.
         stream.seek(startxref, 0)
-        for look in range(5):
+        for look in range(25):  # value extended to cope with more linearized files
             if stream.read(1).isdigit():
                 # This is not a standard PDF, consider adding a warning
                 startxref += look

tests/test_reader.py

@@ -1342,3 +1342,11 @@ def test_iss1652():
     name = "invalidNamesDest.pdf"
     in_pdf = PdfReader(BytesIO(get_pdf_from_url(url, name=name)))
     in_pdf.named_destinations
+
+
+@pytest.mark.enable_socket()
+def test_iss1689():
+    url = "https://github.com/py-pdf/pypdf/files/10948283/error_file_without_data.pdf"
+    name = "iss1689.pdf"
+    in_pdf = PdfReader(BytesIO(get_pdf_from_url(url, name=name)))
+    in_pdf.pages[0]