git_command: read1 needs a size in py3.6

Not setting size causes "TypeError: read1() takes exactly one argument
(0 given)" in Python 3.6.
In Python 3.7 onwards size defaults to -1, which means an arbitrary
number of bytes will be returned.

Compare https://docs.python.org/3.6/library/io.html#io.BufferedReader.read1
and https://docs.python.org/3.7/library/io.html#io.BufferedIOBase.read1
for more details.

Change-Id: Ia4aaf8140ead9493ec650fac167c641569e6a9d8
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/388718
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: Daniel Kutik <daniel.kutik@lavawerk.com>
Commit-Queue: Daniel Kutik <daniel.kutik@lavawerk.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/git_command.py b/git_command.py
index 4b17f78d..2e4974fa 100644
--- a/git_command.py
+++ b/git_command.py
@@ -503,7 +503,8 @@ class GitCommand(object):
             A str containing everything read from the in_stream.
         """
         buffer = ""
-        chunk = in_stream.read1()
+        read_size = 1024 if sys.version_info < (3, 7) else -1
+        chunk = in_stream.read1(read_size)
         while chunk:
             # Convert to str.
             if not hasattr(chunk, "encode"):
@@ -513,7 +514,7 @@ class GitCommand(object):
             out_stream.write(chunk)
             out_stream.flush()
 
-            chunk = in_stream.read1()
+            chunk = in_stream.read1(read_size)
 
         return buffer