annotate tests/test-debian-packages.t @ 37631:2f626233859b

wireproto: implement batching on peer executor interface

This is a bit more complicated than non-batch requests because we
need to buffer sends until the last request arrives *and* we need
to support resolving futures as data arrives from the remote.

In a classical concurrent.futures executor model, the future
"starts" as soon as it is submitted. However, we have nothing to
start until the last command is submitted.

If we did nothing, calling result() would deadlock, since the future
hasn't "started." So in the case where we queue the command, we return
a special future type whose result() will trigger sendcommands().
This eliminates the deadlock potential. It also serves as a check
against callers who may be calling result() prematurely, as it will
prevent any subsequent callcommands() from working. This behavior
is slightly annoying and a bit restrictive. But it's the world
that half duplex connections forces on us.

In order to support streaming responses, we were previously using
a generator. But with a futures-based API, we're using futures
and not generators. So in order to get streaming, we need a
background thread to read data from the server.

The approach taken in this patch is to leverage the ThreadPoolExecutor
from concurrent.futures for managing a background thread. We create
an executor and future that resolves when all response data is
processed (or an error occurs). When exiting the context manager,
we wait on that background reading before returning.

I was hoping we could manually spin up a threading.Thread and this
would be simple. But I ran into a few deadlocks when implementing.
After looking at the source code to concurrent.futures, I figured
it would just be easier to use a ThreadPoolExecutor than implement
all the code needed to manually manage a thread.

To prove this works, a use of the batch API in discovery has been
updated.

Differential Revision: https://phab.mercurial-scm.org/D3269

#require test-repo slow debhelper debdeps

  $ . "$TESTDIR/helpers-testrepo.sh"
  $ testrepohgenv

Ensure debuild doesn't run the testsuite, as that could get silly.
  $ DEB_BUILD_OPTIONS=nocheck
  $ export DEB_BUILD_OPTIONS
  $ OUTPUTDIR=`pwd`
  $ export OUTPUTDIR

  $ cd "$TESTDIR"/..
  $ make deb > $OUTPUTDIR/build.log 2>&1
  $ cd $OUTPUTDIR
  $ ls *.deb | grep -v 'dbg'
  mercurial-common_*.deb (glob)
  mercurial_*.deb (glob)
main deb should have .so but no .py
  $ dpkg --contents mercurial_*.deb | egrep '(localrepo|parsers)'
  * ./usr/lib/python2.7/dist-packages/mercurial/cext/parsers*.so (glob)
mercurial-common should have py but no .so or pyc
  $ dpkg --contents mercurial-common_*.deb | egrep '(localrepo|parsers.*so)'
  * ./usr/lib/python2.7/dist-packages/mercurial/localrepo.py (glob)
zsh completions should be in the common package
  $ dpkg --contents mercurial-common_*.deb | egrep 'zsh.*[^/]$'
  * ./usr/share/zsh/vendor-completions/_hg (glob)
chg should be installed alongside hg, in the 'mercurial' package
  $ dpkg --contents mercurial_*.deb | egrep 'chg$'
  * ./usr/bin/chg (glob)
chg should come with a man page
  $ dpkg --contents mercurial_*.deb | egrep 'man.*chg'
  * ./usr/share/man/man1/chg.1.gz (glob)