Previously, there were following problems with the implmentation:
* Same file handle was being used to read and write. We used to do
`seek(0)` and then `read()`. This had a chance to overwrite file
data. Now we use different file handles to read and write data.
* We were using text streams. Text streams cannot be used with
`bufferring=0`. Now we use binary streams without buffering so that
data is available for reading without any delay.
This reverts commit 66261f1cc. See parent commit for reason; here,
provision worked but `tools/run-dev.py` would give errors.
We need to figure out a test that reproduces these issues, then make a
version of these changes that keeps that test working, before we
re-merge them.
Tweaked by tabbott to not remove it from lister.py, linter_lib, and
friends, since those are intended to support both Python 2 and 3
(we're planning to extract them from the repository).
This causes `upgrade-zulip-from-git`, as well as a no-option run of
`tools/build-release-tarball`, to produce a Zulip install running
Python 3, rather than Python 2. In particular this means that the
virtualenv we create, in which all application code runs, is Python 3.
One shebang line, on `zulip-ec2-configure-interfaces`, explicitly
keeps Python 2, and at least one external ops script, `wal-e`, also
still runs on Python 2. See discussion on the respective previous
commits that made those explicit. There may also be some other
third-party scripts we use, outside of this source tree and running
outside our virtualenv, that still run on Python 2.
This helps make the Zulip development environment somewhat more robust
to new contributors, since it will give them a nice warning if they
try running any of our development tools outside the Zulip virtualenv.
Fixes#3468.
Umair Khan
Greg Price
rht
Greg Price
sinwar
Anders Kaseorg
Tim Abbott
Tim Abbott
Eklavya Sharma