view tests/test-context.py @ 39561:d06834e0f48e

wireprotov2peer: stream decoded responses

Previously, wire protocol version 2 would buffer all response data.
Only once all data was received did we CBOR decode it and resolve
the future associated with the command. This was obviously not
desirable. In future commits that introduce large response payloads,
this caused significant memory bloat and slowed down client
operations due to waiting on the server.

This commit refactors the response handling code so that response
data can be streamed.

Command response objects now contain a buffered CBOR decoder. As
new data arrives, it is fed into the decoder. Decoded objects are
made available to the generator as they are decoded.

Because there is a separate thread processing incoming frames and
feeding data into the response object, there is the potential for
race conditions when mutating response objects. So a lock has been
added to guard access to critical state variables.

Because the generator emitting decoded objects needs to wait on
those objects to become available, we've added an Event for the
generator to wait on so it doesn't busy loop. This does mean
there is the potential for deadlocks. And I'm pretty sure they can
occur in some scenarios. We already have a handful of TODOs around
this. But I've added some more. Fixing this will likely require
moving the background thread receiving frames into clienthandler.
We likely would have done this anyway when implementing the client
bits for the SSH transport.

Test output changes because the initial CBOR map holding the overall
response state is now always handled internally by the response
object.

Differential Revision: https://phab.mercurial-scm.org/D4474

from __future__ import absolute_import, print_function
import os
import stat
import sys
from mercurial.node import hex
from mercurial import (
    context,
    diffutil,
    encoding,
    hg,
    scmutil,
    ui as uimod,
)

print_ = print
def print(*args, **kwargs):
    """print() wrapper that flushes stdout buffers to avoid py3 buffer issues

    We could also just write directly to sys.stdout.buffer the way the
    ui object will, but this was easier for porting the test.
    """
    print_(*args, **kwargs)
    sys.stdout.flush()

def printb(data, end=b'\n'):
    out = getattr(sys.stdout, 'buffer', sys.stdout)
    out.write(data + end)
    out.flush()

u = uimod.ui.load()

repo = hg.repository(u, b'test1', create=1)
os.chdir('test1')

# create 'foo' with fixed time stamp
f = open('foo', 'wb')
f.write(b'foo\n')
f.close()
os.utime('foo', (1000, 1000))

# add+commit 'foo'
repo[None].add([b'foo'])
repo.commit(text=b'commit1', date=b"0 0")

d = repo[None][b'foo'].date()
if os.name == 'nt':
    d = d[:2]
print("workingfilectx.date = (%d, %d)" % d)

# test memctx with non-ASCII commit message

def filectxfn(repo, memctx, path):
    return context.memfilectx(repo, memctx, b"foo", b"")

ctx = context.memctx(repo, [b'tip', None],
                     encoding.tolocal(b"Gr\xc3\xbcezi!"),
                     [b"foo"], filectxfn)
ctx.commit()
for enc in "ASCII", "Latin-1", "UTF-8":
    encoding.encoding = enc
    printb(b"%-8s: %s" % (enc.encode('ascii'), repo[b"tip"].description()))

# test performing a status

def getfilectx(repo, memctx, f):
    fctx = memctx.parents()[0][f]
    data, flags = fctx.data(), fctx.flags()
    if f == b'foo':
        data += b'bar\n'
    return context.memfilectx(
        repo, memctx, f, data, b'l' in flags, b'x' in flags)

ctxa = repo[0]
ctxb = context.memctx(repo, [ctxa.node(), None], b"test diff", [b"foo"],
                      getfilectx, ctxa.user(), ctxa.date())

print(ctxb.status(ctxa))

# test performing a diff on a memctx
diffopts = diffutil.diffallopts(repo.ui, {b'git': True})
for d in ctxb.diff(ctxa, opts=diffopts):
    printb(d, end=b'')

# test safeness and correctness of "ctx.status()"
print('= checking context.status():')

# ancestor "wcctx ~ 2"
actx2 = repo[b'.']

repo.wwrite(b'bar-m', b'bar-m\n', b'')
repo.wwrite(b'bar-r', b'bar-r\n', b'')
repo[None].add([b'bar-m', b'bar-r'])
repo.commit(text=b'add bar-m, bar-r', date=b"0 0")

# ancestor "wcctx ~ 1"
actx1 = repo[b'.']

repo.wwrite(b'bar-m', b'bar-m bar-m\n', b'')
repo.wwrite(b'bar-a', b'bar-a\n', b'')
repo[None].add([b'bar-a'])
repo[None].forget([b'bar-r'])

# status at this point:
#   M bar-m
#   A bar-a
#   R bar-r
#   C foo

from mercurial import scmutil

print('== checking workingctx.status:')

wctx = repo[None]
print('wctx._status=%s' % (str(wctx._status)))

print('=== with "pattern match":')
print(actx1.status(other=wctx,
                   match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wctx._status=%s' % (str(wctx._status)))
print(actx2.status(other=wctx,
                   match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wctx._status=%s' % (str(wctx._status)))

print('=== with "always match" and "listclean=True":')
print(actx1.status(other=wctx, listclean=True))
print('wctx._status=%s' % (str(wctx._status)))
print(actx2.status(other=wctx, listclean=True))
print('wctx._status=%s' % (str(wctx._status)))

print("== checking workingcommitctx.status:")

wcctx = context.workingcommitctx(repo,
                                 scmutil.status([b'bar-m'],
                                                [b'bar-a'],
                                                [],
                                                [], [], [], []),
                                 text=b'', date=b'0 0')
print('wcctx._status=%s' % (str(wcctx._status)))

print('=== with "always match":')
print(actx1.status(other=wcctx))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx))
print('wcctx._status=%s' % (str(wcctx._status)))

print('=== with "always match" and "listclean=True":')
print(actx1.status(other=wcctx, listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx, listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))

print('=== with "pattern match":')
print(actx1.status(other=wcctx,
                   match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx,
                   match=scmutil.matchfiles(repo, [b'bar-m', b'foo'])))
print('wcctx._status=%s' % (str(wcctx._status)))

print('=== with "pattern match" and "listclean=True":')
print(actx1.status(other=wcctx,
                   match=scmutil.matchfiles(repo, [b'bar-r', b'foo']),
                   listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))
print(actx2.status(other=wcctx,
                   match=scmutil.matchfiles(repo, [b'bar-r', b'foo']),
                   listclean=True))
print('wcctx._status=%s' % (str(wcctx._status)))

os.chdir('..')

# test manifestlog being changed
print('== commit with manifestlog invalidated')

repo = hg.repository(u, b'test2', create=1)
os.chdir('test2')

# make some commits
for i in [b'1', b'2', b'3']:
    with open(i, 'wb') as f:
        f.write(i)
    status = scmutil.status([], [i], [], [], [], [], [])
    ctx = context.workingcommitctx(repo, status, text=i, user=b'[e-mail]',
                                   date=(0, 0))
    ctx.p1().manifest() # side effect: cache manifestctx
    n = repo.commitctx(ctx)
    printb(b'commit %s: %s' % (i, hex(n)))

    # touch 00manifest.i mtime so storecache could expire.
    # repo.__dict__['manifestlog'] is deleted by transaction releasefn.
    st = repo.svfs.stat(b'00manifest.i')
    repo.svfs.utime(b'00manifest.i',
                    (st[stat.ST_MTIME] + 1, st[stat.ST_MTIME] + 1))

    # read the file just committed
    try:
        if repo[n][i].data() != i:
            print('data mismatch')
    except Exception as ex:
        print('cannot read data: %r' % ex)

with repo.wlock(), repo.lock(), repo.transaction(b'test'):
    with open(b'4', 'wb') as f:
        f.write(b'4')
    repo.dirstate.normal(b'4')
    repo.commit(b'4')
    revsbefore = len(repo.changelog)
    repo.invalidate(clearfilecache=True)
    revsafter = len(repo.changelog)
    if revsbefore != revsafter:
        print('changeset lost by repo.invalidate()')