@@ -1,5 +1,7 @@
+
+from mmap import mmap
 import re
-import time
+import time as _time
 
 from git.compat import defenc
 from git.objects.util import (
@@ -20,20 +22,33 @@
 import os.path as osp
 
 
+# typing ------------------------------------------------------------------
+
+from typing import Iterator, List, Tuple, Union, TYPE_CHECKING
+
+from git.types import PathLike
+
+if TYPE_CHECKING:
+    from git.refs import SymbolicReference
+    from io import BytesIO
+    from git.config import GitConfigParser, SectionConstraint  # NOQA
+
+# ------------------------------------------------------------------------------
+
 __all__ = ["RefLog", "RefLogEntry"]
 
 
-class RefLogEntry(tuple):
+class RefLogEntry(Tuple[str, str, Actor, Tuple[int, int], str]):
 
     """Named tuple allowing easy access to the revlog data fields"""
     _re_hexsha_only = re.compile('^[0-9A-Fa-f]{40}$')
     __slots__ = ()
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         """Representation of ourselves in git reflog format"""
         return self.format()
 
-    def format(self):
+    def format(self) -> str:
         """:return: a string suitable to be placed in a reflog file"""
         act = self.actor
         time = self.time
@@ -46,35 +61,36 @@ def format(self):
                                                     self.message)
 
     @property
-    def oldhexsha(self):
+    def oldhexsha(self) -> str:
         """The hexsha to the commit the ref pointed to before the change"""
         return self[0]
 
     @property
-    def newhexsha(self):
+    def newhexsha(self) -> str:
         """The hexsha to the commit the ref now points to, after the change"""
         return self[1]
 
     @property
-    def actor(self):
+    def actor(self) -> Actor:
         """Actor instance, providing access"""
         return self[2]
 
     @property
-    def time(self):
+    def time(self) -> Tuple[int, int]:
         """time as tuple:
 
         * [0] = int(time)
         * [1] = int(timezone_offset) in time.altzone format """
         return self[3]
 
     @property
-    def message(self):
+    def message(self) -> str:
         """Message describing the operation that acted on the reference"""
         return self[4]
 
     @classmethod
-    def new(cls, oldhexsha, newhexsha, actor, time, tz_offset, message):  # skipcq: PYL-W0621
+    def new(cls, oldhexsha: str, newhexsha: str, actor: Actor, time: int, tz_offset: int, message: str
+            ) -> 'RefLogEntry':  # skipcq: PYL-W0621
         """:return: New instance of a RefLogEntry"""
         if not isinstance(actor, Actor):
             raise ValueError("Need actor instance, got %s" % actor)
@@ -111,14 +127,15 @@ def from_line(cls, line: bytes) -> 'RefLogEntry':
         # END handle missing end brace
 
         actor = Actor._from_string(info[82:email_end + 1])
-        time, tz_offset = parse_date(info[email_end + 2:])   # skipcq: PYL-W0621
+        time, tz_offset = parse_date(
+            info[email_end + 2:])   # skipcq: PYL-W0621
 
         return RefLogEntry((oldhexsha, newhexsha, actor, (time, tz_offset), msg))
 
 
-class RefLog(list, Serializable):
+class RefLog(List[RefLogEntry], Serializable):
 
-    """A reflog contains reflog entries, each of which defines a certain state
+    """A reflog contains RefLogEntrys, each of which defines a certain state
     of the head in question. Custom query methods allow to retrieve log entries
     by date or by other criteria.
 
@@ -127,11 +144,11 @@ class RefLog(list, Serializable):
 
     __slots__ = ('_path', )
 
-    def __new__(cls, filepath=None):
+    def __new__(cls, filepath: Union[PathLike, None] = None) -> 'RefLog':
         inst = super(RefLog, cls).__new__(cls)
         return inst
 
-    def __init__(self, filepath=None):
+    def __init__(self, filepath: Union[PathLike, None] = None):
         """Initialize this instance with an optional filepath, from which we will
         initialize our data. The path is also used to write changes back using
         the write() method"""
@@ -142,7 +159,8 @@ def __init__(self, filepath=None):
 
     def _read_from_file(self):
         try:
-            fmap = file_contents_ro_filepath(self._path, stream=True, allow_mmap=True)
+            fmap = file_contents_ro_filepath(
+                self._path, stream=True, allow_mmap=True)
         except OSError:
             # it is possible and allowed that the file doesn't exist !
             return
@@ -154,10 +172,10 @@ def _read_from_file(self):
             fmap.close()
         # END handle closing of handle
 
-    #{ Interface
+    # { Interface
 
     @classmethod
-    def from_file(cls, filepath):
+    def from_file(cls, filepath: PathLike) -> 'RefLog':
         """
         :return: a new RefLog instance containing all entries from the reflog
             at the given filepath
@@ -166,7 +184,7 @@ def from_file(cls, filepath):
         return cls(filepath)
 
     @classmethod
-    def path(cls, ref):
+    def path(cls, ref: 'SymbolicReference') -> str:
         """
         :return: string to absolute path at which the reflog of the given ref
             instance would be found. The path is not guaranteed to point to a valid
@@ -175,28 +193,34 @@ def path(cls, ref):
         return osp.join(ref.repo.git_dir, "logs", to_native_path(ref.path))
 
     @classmethod
-    def iter_entries(cls, stream):
+    def iter_entries(cls, stream: Union[str, 'BytesIO', mmap]) -> Iterator[RefLogEntry]:
         """
         :return: Iterator yielding RefLogEntry instances, one for each line read
             sfrom the given stream.
         :param stream: file-like object containing the revlog in its native format
-            or basestring instance pointing to a file to read"""
+            or string instance pointing to a file to read"""
         new_entry = RefLogEntry.from_line
         if isinstance(stream, str):
-            stream = file_contents_ro_filepath(stream)
+            # default args return mmap on py>3
+            _stream = file_contents_ro_filepath(stream)
+            assert isinstance(_stream, mmap)
+        else:
+            _stream = stream
         # END handle stream type
         while True:
-            line = stream.readline()
+            line = _stream.readline()
             if not line:
                 return
             yield new_entry(line.strip())
         # END endless loop
-        stream.close()
 
     @classmethod
-    def entry_at(cls, filepath, index):
-        """:return: RefLogEntry at the given index
+    def entry_at(cls, filepath: PathLike, index: int) -> 'RefLogEntry':
+        """
+        :return: RefLogEntry at the given index
+
         :param filepath: full path to the index file from which to read the entry
+
         :param index: python list compatible index, i.e. it may be negative to
             specify an entry counted from the end of the list
 
@@ -210,21 +234,19 @@ def entry_at(cls, filepath, index):
             if index < 0:
                 return RefLogEntry.from_line(fp.readlines()[index].strip())
             # read until index is reached
+
             for i in range(index + 1):
                 line = fp.readline()
                 if not line:
-                    break
+                    raise IndexError(
+                        f"Index file ended at line {i+1}, before given index was reached")
                 # END abort on eof
             # END handle runup
 
-            if i != index or not line:  # skipcq:PYL-W0631
-                raise IndexError
-            # END handle exception
-
             return RefLogEntry.from_line(line.strip())
         # END handle index
 
-    def to_file(self, filepath):
+    def to_file(self, filepath: PathLike) -> None:
         """Write the contents of the reflog instance to a file at the given filepath.
         :param filepath: path to file, parent directories are assumed to exist"""
         lfd = LockedFD(filepath)
@@ -241,65 +263,75 @@ def to_file(self, filepath):
         # END handle change
 
     @classmethod
-    def append_entry(cls, config_reader, filepath, oldbinsha, newbinsha, message):
+    def append_entry(cls, config_reader: Union[Actor, 'GitConfigParser', 'SectionConstraint', None],
+                     filepath: PathLike, oldbinsha: bytes, newbinsha: bytes, message: str,
+                     write: bool = True) -> 'RefLogEntry':
         """Append a new log entry to the revlog at filepath.
 
         :param config_reader: configuration reader of the repository - used to obtain
-            user information. May also be an Actor instance identifying the committer directly.
-            May also be None
+            user information. May also be an Actor instance identifying the committer directly or None.
         :param filepath: full path to the log file
         :param oldbinsha: binary sha of the previous commit
         :param newbinsha: binary sha of the current commit
         :param message: message describing the change to the reference
         :param write: If True, the changes will be written right away. Otherwise
             the change will not be written
+
         :return: RefLogEntry objects which was appended to the log
+
         :note: As we are append-only, concurrent access is not a problem as we
             do not interfere with readers."""
+
         if len(oldbinsha) != 20 or len(newbinsha) != 20:
             raise ValueError("Shas need to be given in binary format")
         # END handle sha type
         assure_directory_exists(filepath, is_file=True)
         first_line = message.split('\n')[0]
-        committer = isinstance(config_reader, Actor) and config_reader or Actor.committer(config_reader)
+        if isinstance(config_reader, Actor):
+            committer = config_reader  # mypy thinks this is Actor | Gitconfigparser, but why?
+        else:
+            committer = Actor.committer(config_reader)
         entry = RefLogEntry((
             bin_to_hex(oldbinsha).decode('ascii'),
             bin_to_hex(newbinsha).decode('ascii'),
-            committer, (int(time.time()), time.altzone), first_line
+            committer, (int(_time.time()), _time.altzone), first_line
         ))
 
-        lf = LockFile(filepath)
-        lf._obtain_lock_or_raise()
-        fd = open(filepath, 'ab')
-        try:
-            fd.write(entry.format().encode(defenc))
-        finally:
-            fd.close()
-            lf._release_lock()
-        # END handle write operation
-
+        if write:
+            lf = LockFile(filepath)
+            lf._obtain_lock_or_raise()
+            fd = open(filepath, 'ab')
+            try:
+                fd.write(entry.format().encode(defenc))
+            finally:
+                fd.close()
+                lf._release_lock()
+            # END handle write operation
         return entry
 
-    def write(self):
+    def write(self) -> 'RefLog':
         """Write this instance's data to the file we are originating from
         :return: self"""
         if self._path is None:
-            raise ValueError("Instance was not initialized with a path, use to_file(...) instead")
+            raise ValueError(
+                "Instance was not initialized with a path, use to_file(...) instead")
         # END assert path
         self.to_file(self._path)
         return self
 
-    #} END interface
+    # } END interface
 
-    #{ Serializable Interface
-    def _serialize(self, stream):
+    # { Serializable Interface
+    def _serialize(self, stream: 'BytesIO') -> 'RefLog':
         write = stream.write
 
         # write all entries
         for e in self:
             write(e.format().encode(defenc))
         # END for each entry
+        return self
 
-    def _deserialize(self, stream):
+    def _deserialize(self, stream: 'BytesIO') -> 'RefLog':
         self.extend(self.iter_entries(stream))
-    #} END serializable interface
+    # } END serializable interface
+        return self