tests/test-dirstate.t

atomicupdate: add an experimental option to use atomictemp when updating

In some cases Mercurial truncating files when updating causes problems. It can
happens when processes are currently reading the file or with big file or on
NFS mounts.

We add an experimental option to use the atomictemp option of vfs.__call__ in
order to avoid the problem.

The localrepository.wwrite seems to assume the files are created without the
`x` flag; with atomictempfile, the new file might inherit the `x` flag from
the destination. We force remove it afterward. This code could be refactored
and the flag processing could be moved inside vfs.

This patch should be tested with
`--extra-config-opt experimental.update.atomic-file=True`
as we disabled the option by default.

Differential Revision: https://phab.mercurial-scm.org/D1882

------ Test dirstate._dirs refcounting

  $ hg init t
  $ cd t
  $ mkdir -p a/b/c/d
  $ touch a/b/c/d/x
  $ touch a/b/c/d/y
  $ touch a/b/c/d/z
  $ hg ci -Am m
  adding a/b/c/d/x
  adding a/b/c/d/y
  adding a/b/c/d/z
  $ hg mv a z
  moving a/b/c/d/x to z/b/c/d/x
  moving a/b/c/d/y to z/b/c/d/y
  moving a/b/c/d/z to z/b/c/d/z

Test name collisions

  $ rm z/b/c/d/x
  $ mkdir z/b/c/d/x
  $ touch z/b/c/d/x/y
  $ hg add z/b/c/d/x/y
  abort: file 'z/b/c/d/x' in dirstate clashes with 'z/b/c/d/x/y'
  [255]
  $ rm -rf z/b/c/d
  $ touch z/b/c/d
  $ hg add z/b/c/d
  abort: directory 'z/b/c/d' already in dirstate
  [255]

  $ cd ..

Issue1790: dirstate entry locked into unset if file mtime is set into
the future

Prepare test repo:

  $ hg init u
  $ cd u
  $ echo a > a
  $ hg add
  adding a
  $ hg ci -m1

Set mtime of a into the future:

  $ touch -t 202101011200 a

Status must not set a's entry to unset (issue1790):

  $ hg status
  $ hg debugstate
  n 644          2 2021-01-01 12:00:00 a

Test modulo storage/comparison of absurd dates:

#if no-aix
  $ touch -t 195001011200 a
  $ hg st
  $ hg debugstate
  n 644          2 2018-01-19 15:14:08 a
#endif

Verify that exceptions during a dirstate change leave the dirstate
coherent (issue4353)

  $ cat > ../dirstateexception.py <<EOF
  > from __future__ import absolute_import
  > from mercurial import (
  >   error,
  >   extensions,
  >   merge,
  > )
  > 
  > def wraprecordupdates(orig, repo, actions, branchmerge):
  >     raise error.Abort("simulated error while recording dirstateupdates")
  > 
  > def reposetup(ui, repo):
  >     extensions.wrapfunction(merge, 'recordupdates', wraprecordupdates)
  > EOF

  $ hg rm a
  $ hg commit -m 'rm a'
  $ echo "[extensions]" >> .hg/hgrc
  $ echo "dirstateex=../dirstateexception.py" >> .hg/hgrc
  $ hg up 0
  abort: simulated error while recording dirstateupdates
  [255]
  $ hg log -r . -T '{rev}\n'
  1
  $ hg status
  ? a