Small fixes for modern mypy and pylint.

Signed-off-by: Chris Lalancette <clalancette@gmail.com>

Author: clalancette

pycdlib/eltorito.py

@@ -163,18 +163,10 @@ def _checksum(data):
         Returns:
          The checksum of the data.
         """
-        def identity(x):
-            # type: (int) -> int
-            """
-            The identity function so we can use a function for python2/3
-            compatibility.
-            """
-            return x
-
-        if isinstance(data, str):
+        if isinstance(data, bytes):
+            myord = int
+        else:
             myord = ord
-        elif isinstance(data, bytes):
-            myord = identity
         csum = 0
         for i, val in enumerate(data):
             short = (myord(val) << (8 * (i % 2))) & 0xffff

pycdlib/isohybrid.py

@@ -700,6 +700,8 @@ def parse(self, instr):
         if unused2 != 0:
             raise pycdlibexception.PyCdlibInvalidISO('Invalid IsoHybrid unused2')
 
+        psize = 0
+        ecyle = 0
         offset = 32 + struct.calcsize(self.FMT)
         for i in range(1, 5):
             if bytes(bytearray([instr[offset]])) == b'\x80':

pycdlib/pycdlib.py

@@ -3107,6 +3107,9 @@ def _add_hard_link_to_inode(self, data_ino, length, file_mode,
                 # we know for certain that this is Joliet.
                 if self.joliet_vd is None:
                     raise pycdlibexception.PyCdlibInternalError('Tried to link to Joliet record on non-Joliet ISO')
+                if joliet_new_path is None:
+                    # This can really never happen, but here to make mypy happy
+                    raise pycdlibexception.PyCdlibInternalError('Invalid joliet_new_path')
                 # ... to a file on the Joliet filesystem.
                 (new_name, new_parent) = self._joliet_name_and_parent_from_path(joliet_new_path)
                 vd = self.joliet_vd
@@ -4504,6 +4507,9 @@ def modify_file_in_place(self, fp, length, iso_path, rr_name=None,  # pylint: di
                 abs_offset = abs_extent_loc * self.logical_block_size + offset
             elif isinstance(record, udfmod.UDFFileEntry):
                 abs_offset = record.extent_location() * self.logical_block_size
+            else:
+                # This should never happen
+                raise pycdlibexception.PyCdlibInternalError('Invalid record type')
 
             record.set_data_length(length)
             self._cdfp.seek(abs_offset)
@@ -5743,6 +5749,8 @@ def set_hidden(self, iso_path=None, rr_path=None, joliet_path=None):
         elif joliet_path is not None:
             joliet_path_bytes = self._normalize_joliet_path(joliet_path)
             rec = self._find_joliet_record(joliet_path_bytes)
+        else:
+            raise pycdlibexception.PyCdlibInvalidInput('Must provide exactly one of iso_path, rr_path, or joliet_path')
 
         rec.change_existence(True)
 
@@ -5773,6 +5781,8 @@ def clear_hidden(self, iso_path=None, rr_path=None, joliet_path=None):
         elif joliet_path is not None:
             joliet_path_bytes = self._normalize_joliet_path(joliet_path)
             rec = self._find_joliet_record(joliet_path_bytes)
+        else:
+            raise pycdlibexception.PyCdlibInvalidInput('Must provide exactly one of iso_path, rr_path, or joliet_path')
 
         rec.change_existence(False)