view tests/test-inherit-mode.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outdated and unsupported repo format.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 unix-permissions

test that new files created in .hg inherit the permissions from .hg/store

  $ mkdir dir

just in case somebody has a strange $TMPDIR

  $ chmod g-s dir
  $ cd dir

  $ cat >printmodes.py <<EOF
  > import os, sys
  > 
  > allnames = []
  > isdir = {}
  > for root, dirs, files in os.walk(sys.argv[1]):
  >     for d in dirs:
  >         name = os.path.join(root, d)
  >         isdir[name] = 1
  >         allnames.append(name)
  >     for f in files:
  >         name = os.path.join(root, f)
  >         allnames.append(name)
  > allnames.sort()
  > for name in allnames:
  >     suffix = name in isdir and '/' or ''
  >     print '%05o %s%s' % (os.lstat(name).st_mode & 07777, name, suffix)
  > EOF

  $ cat >mode.py <<EOF
  > import sys
  > import os
  > print '%05o' % os.lstat(sys.argv[1]).st_mode
  > EOF

  $ umask 077

  $ hg init repo
  $ cd repo

  $ chmod 0770 .hg/store

before commit
store can be written by the group, other files cannot
store is setgid

  $ python ../printmodes.py .
  00700 ./.hg/
  00600 ./.hg/00changelog.i
  00600 ./.hg/requires
  00770 ./.hg/store/

  $ mkdir dir
  $ touch foo dir/bar
  $ hg ci -qAm 'add files'

after commit
working dir files can only be written by the owner
files created in .hg can be written by the group
(in particular, store/**, dirstate, branch cache file, undo files)
new directories are setgid

  $ python ../printmodes.py .
  00700 ./.hg/
  00600 ./.hg/00changelog.i
  00770 ./.hg/cache/
  00660 ./.hg/cache/branch2-served
  00660 ./.hg/cache/rbc-names-v1
  00660 ./.hg/cache/rbc-revs-v1
  00660 ./.hg/dirstate
  00660 ./.hg/last-message.txt
  00600 ./.hg/requires
  00770 ./.hg/store/
  00660 ./.hg/store/00changelog.i
  00660 ./.hg/store/00manifest.i
  00770 ./.hg/store/data/
  00770 ./.hg/store/data/dir/
  00660 ./.hg/store/data/dir/bar.i
  00660 ./.hg/store/data/foo.i
  00660 ./.hg/store/fncache
  00660 ./.hg/store/phaseroots
  00660 ./.hg/store/undo
  00660 ./.hg/store/undo.backupfiles
  00660 ./.hg/store/undo.phaseroots
  00660 ./.hg/undo.backup.dirstate
  00660 ./.hg/undo.bookmarks
  00660 ./.hg/undo.branch
  00660 ./.hg/undo.desc
  00660 ./.hg/undo.dirstate
  00700 ./dir/
  00600 ./dir/bar
  00600 ./foo

  $ umask 007
  $ hg init ../push

before push
group can write everything

  $ python ../printmodes.py ../push
  00770 ../push/.hg/
  00660 ../push/.hg/00changelog.i
  00660 ../push/.hg/requires
  00770 ../push/.hg/store/

  $ umask 077
  $ hg -q push ../push

after push
group can still write everything

  $ python ../printmodes.py ../push
  00770 ../push/.hg/
  00660 ../push/.hg/00changelog.i
  00770 ../push/.hg/cache/
  00660 ../push/.hg/cache/branch2-base
  00660 ../push/.hg/dirstate
  00660 ../push/.hg/requires
  00770 ../push/.hg/store/
  00660 ../push/.hg/store/00changelog.i
  00660 ../push/.hg/store/00manifest.i
  00770 ../push/.hg/store/data/
  00770 ../push/.hg/store/data/dir/
  00660 ../push/.hg/store/data/dir/bar.i
  00660 ../push/.hg/store/data/foo.i
  00660 ../push/.hg/store/fncache
  00660 ../push/.hg/store/undo
  00660 ../push/.hg/store/undo.backupfiles
  00660 ../push/.hg/store/undo.phaseroots
  00660 ../push/.hg/undo.bookmarks
  00660 ../push/.hg/undo.branch
  00660 ../push/.hg/undo.desc
  00660 ../push/.hg/undo.dirstate


Test that we don't lose the setgid bit when we call chmod.
Not all systems support setgid directories (e.g. HFS+), so
just check that directories have the same mode.

  $ cd ..
  $ hg init setgid
  $ cd setgid
  $ chmod g+rwx .hg/store
  $ chmod g+s .hg/store 2> /dev/null || true
  $ mkdir dir
  $ touch dir/file
  $ hg ci -qAm 'add dir/file'
  $ storemode=`python ../mode.py .hg/store`
  $ dirmode=`python ../mode.py .hg/store/data/dir`
  $ if [ "$storemode" != "$dirmode" ]; then
  >  echo "$storemode != $dirmode"
  > fi
  $ cd ..

  $ cd .. # g-s dir