ROB : Cope with null params for FitH /FitV destination (py-pdf#1145)

iaw pdf spec, page 583

PyPDF2/generic.py

@@ -135,6 +135,9 @@ def writeToStream(
         deprecate_with_replacement("writeToStream", "write_to_stream")
         self.write_to_stream(stream, encryption_key)
 
+    def __repr__(self) -> str:
+        return "NullObject"
+
     @staticmethod
     def readFromStream(stream: StreamType) -> "NullObject":  # pragma: no cover
         deprecate_with_replacement("readFromStream", "read_from_stream")
@@ -1813,9 +1816,15 @@ def __init__(
                 self[NameObject(TA.TOP)],
             ) = args
         elif typ in [TF.FIT_H, TF.FIT_BH]:
-            (self[NameObject(TA.TOP)],) = args
+            try:  # Prefered to be more robust not only to null parameters
+                (self[NameObject(TA.TOP)],) = args
+            except Exception:
+                (self[NameObject(TA.TOP)],) = (NullObject(),)
         elif typ in [TF.FIT_V, TF.FIT_BV]:
-            (self[NameObject(TA.LEFT)],) = args
+            try:  # Prefered to be more robust not only to null parameters
+                (self[NameObject(TA.LEFT)],) = args
+            except Exception:
+                (self[NameObject(TA.LEFT)],) = (NullObject(),)
         elif typ in [TF.FIT, TF.FIT_B]:
             pass
         else:

tests/test_merger.py

@@ -288,3 +288,11 @@ def test_sweep_indirect_list_newobj_is_None():
 
     # cleanup
     os.remove("tmp-merger-do-not-commit.pdf")
+
+
+def test_iss1145():
+    # issue with FitH destination with null param
+    url = "https://github.com/py-pdf/PyPDF2/files/9164743/file-0.pdf"
+    name = "iss1145.pdf"
+    merger = PdfMerger()
+    merger.append(PdfReader(BytesIO(get_pdf_from_url(url, name=name))))