ROB: Missing basefont entry in type 3 font (#2469)

closes #2289

pypdf/_page.py

@@ -2340,7 +2340,10 @@ def process_font(f: DictionaryObject) -> None:
  )
  ):
  # the list comprehension ensures there is FontFile
- emb.add(cast(str, f["/BaseFont"]))
+ try:
+ emb.add(cast(str, f["/BaseFont"]))
+ except KeyError:
+ emb.add("(" + cast(str, f["/Subtype"]) + ")")
 
  if "/DR" in obj and "/Font" in cast(DictionaryObject, obj["/DR"]):
  for f in cast(DictionaryObject, cast(DictionaryObject, obj["/DR"])["/Font"]):

tests/test_page.py

@@ -1398,3 +1398,12 @@ def visitor_lvl(text, cm, tm, fontdict, fontsize) -> None:
  "hotels, short-term rentals, etc., advertised rates: mandatory fee disclosures, SB 683",
  "housing rental properties advertised rates: disclosures, SB 611",
  ]
+
+
+@pytest.mark.enable_socket()
+def test_missing_basefont_in_type3():
+ """Cf #2289"""
+ url = "https://github.com/py-pdf/pypdf/files/13307713/missing-base-font.pdf"
+ name = "missing-base-font.pdf"
+ reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+ reader.pages[0]._get_fonts()