Mercurial > hg
view tests/test-rebuildstate.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
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 13 Apr 2018 11:02:34 -0700 |
parents | fce4ed2912bb |
children | 74c5ddd97008 |
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$ cat > adddrop.py <<EOF > from mercurial import registrar > cmdtable = {} > command = registrar.command(cmdtable) > @command(b'debugadddrop', > [('', 'drop', False, 'drop file from dirstate', 'FILE'), > ('', 'normal-lookup', False, 'add file to dirstate', 'FILE')], > 'hg debugadddrop') > def debugadddrop(ui, repo, *pats, **opts): > '''Add or drop unnamed arguments to or from the dirstate''' > drop = opts.get('drop') > nl = opts.get('normal_lookup') > if nl and drop: > raise error.Abort('drop and normal-lookup are mutually exclusive') > wlock = repo.wlock() > try: > for file in pats: > if opts.get('normal_lookup'): > repo.dirstate.normallookup(file) > else: > repo.dirstate.drop(file) > > repo.dirstate.write(repo.currenttransaction()) > finally: > wlock.release() > EOF $ echo "[extensions]" >> $HGRCPATH $ echo "debugadddrop=`pwd`/adddrop.py" >> $HGRCPATH basic test for hg debugrebuildstate $ hg init repo $ cd repo $ touch foo bar $ hg ci -Am 'add foo bar' adding bar adding foo $ touch baz $ hg add baz $ hg rm bar $ hg debugrebuildstate state dump after $ hg debugstate --nodates | sort n 0 -1 unset bar n 0 -1 unset foo $ hg debugadddrop --normal-lookup file1 file2 $ hg debugadddrop --drop bar $ hg debugadddrop --drop $ hg debugstate --nodates n 0 -1 unset file1 n 0 -1 unset file2 n 0 -1 unset foo $ hg debugrebuildstate status $ hg st -A ! bar ? baz C foo Test debugdirstate --minimal where a file is not in parent manifest but in the dirstate $ touch foo bar qux $ hg add qux $ hg remove bar $ hg status -A A qux R bar ? baz C foo $ hg debugadddrop --normal-lookup baz $ hg debugdirstate --nodates r 0 0 * bar (glob) n 0 -1 * baz (glob) n 644 0 * foo (glob) a 0 -1 * qux (glob) $ hg debugrebuilddirstate --minimal $ hg debugdirstate --nodates r 0 0 * bar (glob) n 644 0 * foo (glob) a 0 -1 * qux (glob) $ hg status -A A qux R bar ? baz C foo Test debugdirstate --minimal where file is in the parent manifest but not the dirstate $ hg manifest bar foo $ hg status -A A qux R bar ? baz C foo $ hg debugdirstate --nodates r 0 0 * bar (glob) n 644 0 * foo (glob) a 0 -1 * qux (glob) $ hg debugadddrop --drop foo $ hg debugdirstate --nodates r 0 0 * bar (glob) a 0 -1 * qux (glob) $ hg debugrebuilddirstate --minimal $ hg debugdirstate --nodates r 0 0 * bar (glob) n 0 -1 * foo (glob) a 0 -1 * qux (glob) $ hg status -A A qux R bar ? baz C foo