BUG: Title sometimes is bytes and not str (#2930)

Closes #2929.

Author: reformy

pypdf/_doc_common.py

@@ -121,6 +121,8 @@ def _get_text(self, key: str) -> Optional[str]:
         retval = self.get(key, None)
         if isinstance(retval, TextStringObject):
             return retval
+        if isinstance(retval, ByteStringObject):
+            return str(retval)
         return None
 
     @property

pypdf/generic/_base.py

@@ -619,6 +619,15 @@ def write_to_stream(
         stream.write(binascii.hexlify(self))
         stream.write(b">")
 
+    def __str__(self) -> str:
+        charset_to_try = ["utf-16"] + list(NameObject.CHARSETS)
+        for enc in charset_to_try:
+            try:
+                return self.decode(enc)
+            except UnicodeDecodeError:
+                pass
+        raise PdfReadError("Cannot decode ByteStringObject.")
+
 
 class TextStringObject(str, PdfObject):  # noqa: SLOT000
     """

resources/bytes.pdf

@@ -108,9 +108,18 @@ def test_read_metadata(pdf_path, expected):
         docinfo.modification_date
         docinfo.modification_date_raw
         if "/Title" in metadict:
+            assert isinstance(docinfo.title, str)
             assert metadict["/Title"] == docinfo.title
 
 
+def test_read_metadata_title_is_utf8():
+    with open(RESOURCE_ROOT / "bytes.pdf", "rb") as inputfile:
+        reader = PdfReader(inputfile)
+        title = reader.metadata.title
+        # Should be a str.
+        assert title == "Microsoft Word - トランスバース社買収電話会議英語Final.docx"
+
+
 def test_iss1943():
     with PdfReader(RESOURCE_ROOT / "crazyones.pdf") as reader:
         docinfo = reader.metadata