view tests/test-chg.t @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

#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('crash')
  > def pagercrash(ui, repo, *pats, **opts):
  >     ui.write('going to crash\n')
  >     raise Exception('.')
  > EOF

  $ cat > $TESTTMP/fakepager.py <<EOF
  > import sys, 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
  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 ..