tests/test-chg.t

bundle2: implement consume() API on unbundlepart

We want bundle parts to not be seekable by default. That means
eliminating the generic seek() method.

A common pattern in bundle2.py is to seek to the end of the part
data. This is mainly used by the part iteration code to ensure
the underlying stream is advanced to the next bundle part.

In this commit, we establish a dedicated API for consuming a
bundle2 part data. We switch users of seek() to it.

The old implementation of seek(0, os.SEEK_END) would effectively
call self.read(). The new implementation calls self.read(32768)
in a loop. The old implementation would therefore assemble a
buffer to hold all remaining data being seeked over. For seeking
over large bundle parts, this would involve a large allocation and
a lot of overhead to collect intermediate data! This overhead can
be seen in the results for `hg perfbundleread`:

! bundle2 iterparts()
! wall 10.891305 comb 10.820000 user 7.990000 sys 2.830000 (best of 3)
! wall 8.070791 comb 8.060000 user 7.180000 sys 0.880000 (best of 3)
! bundle2 part seek()
! wall 12.991478 comb 10.390000 user 7.720000 sys 2.670000 (best of 3)
! wall 10.370142 comb 10.350000 user 7.430000 sys 2.920000 (best of 3)

Of course, skipping over large payload data isn't likely very common.
So I doubt the performance wins will be observed in the wild.

Differential Revision: https://phab.mercurial-scm.org/D1388

#require chg

  $ cp $HGRCPATH $HGRCPATH.orig

init repo

  $ chg init foo
  $ cd foo

ill-formed config

  $ chg status
  $ echo '=brokenconfig' >> $HGRCPATH
  $ chg status
  hg: parse error at * (glob)
  [255]

  $ cp $HGRCPATH.orig $HGRCPATH

long socket path

  $ sockpath=$TESTTMP/this/path/should/be/longer/than/one-hundred-and-seven/characters/where/107/is/the/typical/size/limit/of/unix-domain-socket
  $ mkdir -p $sockpath
  $ bakchgsockname=$CHGSOCKNAME
  $ CHGSOCKNAME=$sockpath/server
  $ export CHGSOCKNAME
  $ chg root
  $TESTTMP/foo
  $ rm -rf $sockpath
  $ CHGSOCKNAME=$bakchgsockname
  $ export CHGSOCKNAME

  $ cd ..

editor
------

  $ cat >> pushbuffer.py <<EOF
  > def reposetup(ui, repo):
  >     repo.ui.pushbuffer(subproc=True)
  > EOF

  $ chg init editor
  $ cd editor

by default, system() should be redirected to the client:

  $ touch foo
  $ CHGDEBUG= HGEDITOR=cat chg ci -Am channeled --edit 2>&1 \
  > | egrep "HG:|run 'cat"
  chg: debug: * run 'cat "*"' at '$TESTTMP/editor' (glob)
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: added foo

but no redirection should be made if output is captured:

  $ touch bar
  $ CHGDEBUG= HGEDITOR=cat chg ci -Am bufferred --edit \
  > --config extensions.pushbuffer="$TESTTMP/pushbuffer.py" 2>&1 \
  > | egrep "HG:|run 'cat"
  [1]

check that commit commands succeeded:

  $ hg log -T '{rev}:{desc}\n'
  1:bufferred
  0:channeled

  $ cd ..

pager
-----

  $ cat >> fakepager.py <<EOF
  > import sys
  > for line in sys.stdin:
  >     sys.stdout.write('paged! %r\n' % line)
  > EOF

enable pager extension globally, but spawns the master server with no tty:

  $ chg init pager
  $ cd pager
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > pager =
  > [pager]
  > pager = $PYTHON $TESTTMP/fakepager.py
  > EOF
  $ chg version > /dev/null
  $ touch foo
  $ chg ci -qAm foo

pager should be enabled if the attached client has a tty:

  $ chg log -l1 -q --config ui.formatted=True
  paged! '0:1f7b0de80e11\n'
  $ chg log -l1 -q --config ui.formatted=False
  0:1f7b0de80e11

chg waits for pager if runcommand raises

  $ cat > $TESTTMP/crash.py <<EOF
  > from mercurial import registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'crash')
  > def pagercrash(ui, repo, *pats, **opts):
  >     ui.write('going to crash\n')
  >     raise Exception('.')
  > EOF

  $ cat > $TESTTMP/fakepager.py <<EOF
  > from __future__ import absolute_import
  > import sys
  > import time
  > for line in iter(sys.stdin.readline, ''):
  >     if 'crash' in line: # only interested in lines containing 'crash'
  >         # if chg exits when pager is sleeping (incorrectly), the output
  >         # will be captured by the next test case
  >         time.sleep(1)
  >         sys.stdout.write('crash-pager: %s' % line)
  > EOF

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > crash = $TESTTMP/crash.py
  > EOF

  $ chg crash --pager=on --config ui.formatted=True 2>/dev/null
  crash-pager: going to crash
  [255]

  $ cd ..

server lifecycle
----------------

chg server should be restarted on code change, and old server will shut down
automatically. In this test, we use the following time parameters:

 - "sleep 1" to make mtime different
 - "sleep 2" to notice mtime change (polling interval is 1 sec)

set up repository with an extension:

  $ chg init extreload
  $ cd extreload
  $ touch dummyext.py
  $ cat <<EOF >> .hg/hgrc
  > [extensions]
  > dummyext = dummyext.py
  > EOF

isolate socket directory for stable result:

  $ OLDCHGSOCKNAME=$CHGSOCKNAME
  $ mkdir chgsock
  $ CHGSOCKNAME=`pwd`/chgsock/server

warm up server:

  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

new server should be started if extension modified:

  $ sleep 1
  $ touch dummyext.py
  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: * instruction: unlink $TESTTMP/extreload/chgsock/server-* (glob)
  chg: debug: * instruction: reconnect (glob)
  chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

old server will shut down, while new server should still be reachable:

  $ sleep 2
  $ CHGDEBUG= chg log 2>&1 | (egrep 'instruction|start' || true)

socket file should never be unlinked by old server:
(simulates unowned socket by updating mtime, which makes sure server exits
at polling cycle)

  $ ls chgsock/server-*
  chgsock/server-* (glob)
  $ touch chgsock/server-*
  $ sleep 2
  $ ls chgsock/server-*
  chgsock/server-* (glob)

since no server is reachable from socket file, new server should be started:
(this test makes sure that old server shut down automatically)

  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

shut down servers and restore environment:

  $ rm -R chgsock
  $ CHGSOCKNAME=$OLDCHGSOCKNAME
  $ cd ..