Upgrade Python syntax with pyupgrade --py37-plus

18 files changed, 43 insertions, 47 deletions

diff --git a/doc/source/conf.py b/doc/source/conf.py
index 3ab15ab..b387f60 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 # GitDB documentation build configuration file, created by
 # sphinx-quickstart on Wed Jun 30 00:01:32 2010.
@@ -38,8 +37,8 @@ source_suffix = '.rst'
 master_doc = 'index'
 
 # General information about the project.
-project = u'GitDB'
-copyright = u'2011, Sebastian Thiel'
+project = 'GitDB'
+copyright = '2011, Sebastian Thiel'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -172,8 +171,8 @@ htmlhelp_basename = 'GitDBdoc'
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
 latex_documents = [
-    ('index', 'GitDB.tex', u'GitDB Documentation',
-     u'Sebastian Thiel', 'manual'),
+    ('index', 'GitDB.tex', 'GitDB Documentation',
+     'Sebastian Thiel', 'manual'),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
diff --git a/gitdb/db/base.py b/gitdb/db/base.py
index f0b8a05..e89052e 100644
--- a/gitdb/db/base.py
+++ b/gitdb/db/base.py
@@ -22,7 +22,7 @@ from functools import reduce
 __all__ = ('ObjectDBR', 'ObjectDBW', 'FileDBBase', 'CompoundDB', 'CachingDB')
 
 
-class ObjectDBR(object):
+class ObjectDBR:
 
     """Defines an interface for object database lookup.
     Objects are identified either by their 20 byte bin sha"""
@@ -63,7 +63,7 @@ class ObjectDBR(object):
     #} END query interface
 
 
-class ObjectDBW(object):
+class ObjectDBW:
 
     """Defines an interface to create objects in the database"""
 
@@ -105,7 +105,7 @@ class ObjectDBW(object):
     #} END edit interface
 
 
-class FileDBBase(object):
+class FileDBBase:
 
     """Provides basic facilities to retrieve files of interest, including
     caching facilities to help mapping hexsha's to objects"""
@@ -117,7 +117,7 @@ class FileDBBase(object):
         **Note:** The base will not perform any accessablity checking as the base
             might not yet be accessible, but become accessible before the first
             access."""
-        super(FileDBBase, self).__init__()
+        super().__init__()
         self._root_path = root_path
 
     #{ Interface
@@ -133,7 +133,7 @@ class FileDBBase(object):
     #} END interface
 
 
-class CachingDB(object):
+class CachingDB:
 
     """A database which uses caches to speed-up access"""
 
@@ -176,7 +176,7 @@ class CompoundDB(ObjectDBR, LazyMixin, CachingDB):
         elif attr == '_db_cache':
             self._db_cache = dict()
         else:
-            super(CompoundDB, self)._set_cache_(attr)
+            super()._set_cache_(attr)
 
     def _db_query(self, sha):
         """:return: database containing the given 20 byte sha
diff --git a/gitdb/db/git.py b/gitdb/db/git.py
index 7a43d72..e2cb468 100644
--- a/gitdb/db/git.py
+++ b/gitdb/db/git.py
@@ -39,7 +39,7 @@ class GitDB(FileDBBase, ObjectDBW, CompoundDB):
 
     def __init__(self, root_path):
         """Initialize ourselves on a git objects directory"""
-        super(GitDB, self).__init__(root_path)
+        super().__init__(root_path)
 
     def _set_cache_(self, attr):
         if attr == '_dbs' or attr == '_loose_db':
@@ -68,7 +68,7 @@ class GitDB(FileDBBase, ObjectDBW, CompoundDB):
             # finally set the value
             self._loose_db = loose_db
         else:
-            super(GitDB, self)._set_cache_(attr)
+            super()._set_cache_(attr)
         # END handle attrs
 
     #{ ObjectDBW interface
diff --git a/gitdb/db/loose.py b/gitdb/db/loose.py
index a63a2ef..4ef7750 100644
--- a/gitdb/db/loose.py
+++ b/gitdb/db/loose.py
@@ -75,7 +75,7 @@ class LooseObjectDB(FileDBBase, ObjectDBR, ObjectDBW):
         new_objects_mode = int("644", 8)
 
     def __init__(self, root_path):
-        super(LooseObjectDB, self).__init__(root_path)
+        super().__init__(root_path)
         self._hexsha_to_file = dict()
         # Additional Flags - might be set to 0 after the first failure
         # Depending on the root, this might work for some mounts, for others not, which
@@ -151,7 +151,7 @@ class LooseObjectDB(FileDBBase, ObjectDBR, ObjectDBW):
         """:raise TypeError: if the stream does not support the Sha1Writer interface"""
         if stream is not None and not isinstance(stream, Sha1Writer):
             raise TypeError("Output stream musst support the %s interface" % Sha1Writer.__name__)
-        return super(LooseObjectDB, self).set_ostream(stream)
+        return super().set_ostream(stream)
 
     def info(self, sha):
         m = self._map_loose_object(sha)
diff --git a/gitdb/db/mem.py b/gitdb/db/mem.py
index b2542ff..1b954cb 100644
--- a/gitdb/db/mem.py
+++ b/gitdb/db/mem.py
@@ -37,7 +37,7 @@ class MemoryDB(ObjectDBR, ObjectDBW):
     exists in the target storage before introducing actual IO"""
 
     def __init__(self):
-        super(MemoryDB, self).__init__()
+        super().__init__()
         self._db = LooseObjectDB("path/doesnt/matter")
 
         # maps 20 byte shas to their OStream objects
diff --git a/gitdb/db/pack.py b/gitdb/db/pack.py
index 90de02b..1ce786b 100644
--- a/gitdb/db/pack.py
+++ b/gitdb/db/pack.py
@@ -39,7 +39,7 @@ class PackedDB(FileDBBase, ObjectDBR, CachingDB, LazyMixin):
     _sort_interval = 500
 
     def __init__(self, root_path):
-        super(PackedDB, self).__init__(root_path)
+        super().__init__(root_path)
         # list of lists with three items:
         # * hits - number of times the pack was hit with a request
         # * entity - Pack entity instance
diff --git a/gitdb/db/ref.py b/gitdb/db/ref.py
index 2bb1de7..6bb2a64 100644
--- a/gitdb/db/ref.py
+++ b/gitdb/db/ref.py
@@ -20,7 +20,7 @@ class ReferenceDB(CompoundDB):
     ObjectDBCls = None
 
     def __init__(self, ref_file):
-        super(ReferenceDB, self).__init__()
+        super().__init__()
         self._ref_file = ref_file
 
     def _set_cache_(self, attr):
@@ -28,7 +28,7 @@ class ReferenceDB(CompoundDB):
             self._dbs = list()
             self._update_dbs_from_ref_file()
         else:
-            super(ReferenceDB, self)._set_cache_(attr)
+            super()._set_cache_(attr)
         # END handle attrs
 
     def _update_dbs_from_ref_file(self):
@@ -44,7 +44,7 @@ class ReferenceDB(CompoundDB):
         try:
             with codecs.open(self._ref_file, 'r', encoding="utf-8") as f:
                 ref_paths = [l.strip() for l in f]
-        except (OSError, IOError):
+        except OSError:
             pass
         # END handle alternates
 
@@ -79,4 +79,4 @@ class ReferenceDB(CompoundDB):
     def update_cache(self, force=False):
         # re-read alternates and update databases
         self._update_dbs_from_ref_file()
-        return super(ReferenceDB, self).update_cache(force)
+        return super().update_cache(force)
diff --git a/gitdb/fun.py b/gitdb/fun.py
index abb4277..a4454de 100644
--- a/gitdb/fun.py
+++ b/gitdb/fun.py
@@ -113,7 +113,7 @@ def delta_chunk_apply(dc, bbuf, write):
     # END handle chunk mode
 
 
-class DeltaChunk(object):
+class DeltaChunk:
 
     """Represents a piece of a delta, it can either add new data, or copy existing
     one from a source buffer"""
diff --git a/gitdb/pack.py b/gitdb/pack.py
index 0b26c12..cabce4c 100644
--- a/gitdb/pack.py
+++ b/gitdb/pack.py
@@ -170,7 +170,7 @@ def write_stream_to_pack(read, write, zstream, base_crc=None):
 #} END utilities
 
 
-class IndexWriter(object):
+class IndexWriter:
 
     """Utility to cache index information, allowing to write all information later
     in one go to the given stream
@@ -257,7 +257,7 @@ class PackIndexFile(LazyMixin):
     index_version_default = 2
 
     def __init__(self, indexpath):
-        super(PackIndexFile, self).__init__()
+        super().__init__()
         self._indexpath = indexpath
 
     def close(self):
diff --git a/gitdb/stream.py b/gitdb/stream.py
index 37380ad..222b843 100644
--- a/gitdb/stream.py
+++ b/gitdb/stream.py
@@ -219,13 +219,13 @@ class DecompressMemMapReader(LazyMixin):
         # END clamp size
 
         if size == 0:
-            return bytes()
+            return b''
         # END handle depletion
 
         # deplete the buffer, then just continue using the decompress object
         # which has an own buffer. We just need this to transparently parse the
         # header from the zlib stream
-        dat = bytes()
+        dat = b''
         if self._buf:
             if self._buflen >= size:
                 # have enough data
@@ -553,7 +553,7 @@ class DeltaApplyReader(LazyMixin):
 
 #{ W Streams
 
-class Sha1Writer(object):
+class Sha1Writer:
 
     """Simple stream writer which produces a sha whenever you like as it degests
     everything it is supposed to write"""
@@ -650,7 +650,7 @@ class FDCompressedSha1Writer(Sha1Writer):
     exc = IOError("Failed to write all bytes to filedescriptor")
 
     def __init__(self, fd):
-        super(FDCompressedSha1Writer, self).__init__()
+        super().__init__()
         self.fd = fd
         self.zip = zlib.compressobj(zlib.Z_BEST_SPEED)
 
@@ -677,7 +677,7 @@ class FDCompressedSha1Writer(Sha1Writer):
     #} END stream interface
 
 
-class FDStream(object):
+class FDStream:
 
     """A simple wrapper providing the most basic functions on a file descriptor
     with the fileobject interface. Cannot use os.fdopen as the resulting stream
@@ -711,7 +711,7 @@ class FDStream(object):
         close(self._fd)
 
 
-class NullStream(object):
+class NullStream:
 
     """A stream that does nothing but providing a stream interface.
     Use it like /dev/null"""
diff --git a/gitdb/test/db/test_ref.py b/gitdb/test/db/test_ref.py
index 2049698..664aa54 100644
--- a/gitdb/test/db/test_ref.py
+++ b/gitdb/test/db/test_ref.py
@@ -23,7 +23,7 @@ class TestReferenceDB(TestDBBase):
         The list can be empty"""
         with open(alt_path, "wb") as alt_file:
             for alt in alt_list:
-                alt_file.write(alt.encode("utf-8") + "\n".encode("ascii"))
+                alt_file.write(alt.encode("utf-8") + b"\n")
 
     @with_rw_directory
     def test_writing(self, path):
diff --git a/gitdb/test/lib.py b/gitdb/test/lib.py
index 465a899..da59d3b 100644
--- a/gitdb/test/lib.py
+++ b/gitdb/test/lib.py
@@ -40,7 +40,7 @@ class TestBase(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         try:
-            super(TestBase, cls).setUpClass()
+            super().setUpClass()
         except AttributeError:
             pass
 
@@ -70,7 +70,7 @@ def with_rw_directory(func):
             try:
                 return func(self, path)
             except Exception:
-                sys.stderr.write("Test {}.{} failed, output is at {!r}\n".format(type(self).__name__, func.__name__, path))
+                sys.stderr.write(f"Test {type(self).__name__}.{func.__name__} failed, output is at {path!r}\n")
                 keep = True
                 raise
         finally:
@@ -161,7 +161,7 @@ def make_memory_file(size_in_bytes, randomize=False):
 #{ Stream Utilities
 
 
-class DummyStream(object):
+class DummyStream:
 
     def __init__(self):
         self.was_read = False
diff --git a/gitdb/test/performance/test_pack.py b/gitdb/test/performance/test_pack.py
index 643186b..f034baf 100644
--- a/gitdb/test/performance/test_pack.py
+++ b/gitdb/test/performance/test_pack.py
@@ -3,7 +3,6 @@
 # This module is part of GitDB and is released under
 # the New BSD License: http://www.opensource.org/licenses/bsd-license.php
 """Performance tests for object store"""
-from __future__ import print_function
 
 from gitdb.test.performance.lib import (
     TestBigRepoR
diff --git a/gitdb/test/performance/test_pack_streaming.py b/gitdb/test/performance/test_pack_streaming.py
index 5bf6790..db790f1 100644
--- a/gitdb/test/performance/test_pack_streaming.py
+++ b/gitdb/test/performance/test_pack_streaming.py
@@ -3,7 +3,6 @@
 # This module is part of GitDB and is released under
 # the New BSD License: http://www.opensource.org/licenses/bsd-license.php
 """Specific test for pack streams only"""
-from __future__ import print_function
 
 from gitdb.test.performance.lib import (
     TestBigRepoR
diff --git a/gitdb/test/performance/test_stream.py b/gitdb/test/performance/test_stream.py
index 9a8b15b..91dc891 100644
--- a/gitdb/test/performance/test_stream.py
+++ b/gitdb/test/performance/test_stream.py
@@ -3,7 +3,6 @@
 # This module is part of GitDB and is released under
 # the New BSD License: http://www.opensource.org/licenses/bsd-license.php
 """Performance data streaming performance"""
-from __future__ import print_function
 
 from gitdb.test.performance.lib import TestBigRepoR
 from gitdb.db import LooseObjectDB
diff --git a/gitdb/test/test_example.py b/gitdb/test/test_example.py
index 6e80bf5..cc4d40d 100644
--- a/gitdb/test/test_example.py
+++ b/gitdb/test/test_example.py
@@ -32,7 +32,7 @@ class TestExamples(TestBase):
             pass
         # END ignore exception if there are no loose objects
 
-        data = "my data".encode("ascii")
+        data = b"my data"
         istream = IStream("blob", len(data), BytesIO(data))
 
         # the object does not yet have a sha
diff --git a/gitdb/test/test_stream.py b/gitdb/test/test_stream.py
index 5d4b93d..5e2e1ba 100644
--- a/gitdb/test/test_stream.py
+++ b/gitdb/test/test_stream.py
@@ -115,13 +115,13 @@ class TestStream(TestBase):
 
     def test_sha_writer(self):
         writer = Sha1Writer()
-        assert 2 == writer.write("hi".encode("ascii"))
+        assert 2 == writer.write(b"hi")
         assert len(writer.sha(as_hex=1)) == 40
         assert len(writer.sha(as_hex=0)) == 20
 
         # make sure it does something ;)
         prev_sha = writer.sha()
-        writer.write("hi again".encode("ascii"))
+        writer.write(b"hi again")
         assert writer.sha() != prev_sha
 
     def test_compressed_writer(self):
diff --git a/gitdb/util.py b/gitdb/util.py
index f9f8c0e..3151c06 100644
--- a/gitdb/util.py
+++ b/gitdb/util.py
@@ -94,7 +94,7 @@ from gitdb.const import (
 #{ compatibility stuff ...
 
 
-class _RandomAccessBytesIO(object):
+class _RandomAccessBytesIO:
 
     """Wrapper to provide required functionality in case memory maps cannot or may
     not be used. This is only really required in python 2.4"""
@@ -131,7 +131,7 @@ def byte_ord(b):
 #{ Routines
 
 
-def make_sha(source=''.encode("ascii")):
+def make_sha(source=b''):
     """A python2.4 workaround for the sha/hashlib module fiasco
 
     **Note** From the dulwich project """
@@ -151,7 +151,7 @@ def allocate_memory(size):
 
     try:
         return mmap.mmap(-1, size)  # read-write by default
-    except EnvironmentError:
+    except OSError:
         # setup real memory instead
         # this of course may fail if the amount of memory is not available in
         # one chunk - would only be the case in python 2.4, being more likely on
@@ -174,7 +174,7 @@ def file_contents_ro(fd, stream=False, allow_mmap=True):
             # supports stream and random access
             try:
                 return mmap.mmap(fd, 0, access=mmap.ACCESS_READ)
-            except EnvironmentError:
+            except OSError:
                 # python 2.4 issue, 0 wants to be the actual size
                 return mmap.mmap(fd, os.fstat(fd).st_size, access=mmap.ACCESS_READ)
             # END handle python 2.4
@@ -234,7 +234,7 @@ def to_bin_sha(sha):
 
 #{ Utilities
 
-class LazyMixin(object):
+class LazyMixin:
 
     """
     Base class providing an interface to lazily retrieve attribute values upon
@@ -266,7 +266,7 @@ class LazyMixin(object):
         pass
 
 
-class LockedFD(object):
+class LockedFD:
 
     """
     This class facilitates a safe read and write operation to a file on disk.
@@ -327,7 +327,7 @@ class LockedFD(object):
                 self._fd = fd
             # END handle file descriptor
         except OSError as e:
-            raise IOError("Lock at %r could not be obtained" % self._lockfilepath()) from e
+            raise OSError("Lock at %r could not be obtained" % self._lockfilepath()) from e
         # END handle lock retrieval
 
         # open actual file if required