view tests/test-chg.t @ 33289:abd7dedbaa36

sparse: vendor Facebook-developed extension

Facebook has developed an extension to enable "sparse" checkouts -
a working directory with a subset of files. This feature is a critical
component in enabling repositories to scale to infinite number of
files while retaining reasonable performance. It's worth noting
that sparse checkout is only one possible solution to this problem:
another is virtual filesystems that realize files on first access.
But given that virtual filesystems may not be accessible to all
users, sparse checkout is necessary as a fallback.

Per mailing list discussion at
https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-March/095868.html
we want to add sparse checkout to the Mercurial distribution via
roughly the following mechanism:

1. Vendor extension as-is with minimal modifications (this patch)
2. Refactor extension so it is more clearly experimental and inline
   with Mercurial practices
3. Move code from extension into core where possible
4. Drop experimental labeling and/or move feature into core
   after sign-off from narrow clone feature owners

This commit essentially copies the sparse extension and tests
from revision 71e0a2aeca92a4078fe1b8c76e32c88ff1929737 of the
https://bitbucket.org/facebook/hg-experimental repository.

A list of modifications made as part of vendoring is as follows:

* "EXPERIMENTAL" added to module docstring
* Imports were changed to match Mercurial style conventions
* "testedwith" value was updated to core Mercurial special value and
  comment boilerplate was inserted
* A "clone_sparse" function was renamed to "clonesparse" to appease
  the style checker
* Paths to the sparse extension in tests reflect built-in location
* test-sparse-extensions.t was renamed to test-sparse-fsmonitor.t
  and references to "simplecache" were removed. The test always skips
  because it isn't trivial to run it given the way we currently run
  fsmonitor tests
* A double empty line was removed from test-sparse-profiles.t

There are aspects of the added code that are obviously not ideal.
The goal is to make a minimal number of modifications as part of
the vendoring to make it easier to track changes from the original
implementation. Refactoring will occur in subsequent patches.

#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
  > 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 ..