tests/test-purge.t

tests: add test-remotefilelog-strip.t to demonstrate an issue with linknodes

### Background

Every time a commit is modified, remotefilelog updates the metadata for the file
object to point to the new commit (I believe that this is different from
non-remotefilelog hg, which leaves the linkrevs pointing to the obsolete
commits; doing otherwise would involve changing data in the middle of revlogs).

With `hg strip` (or other things that use repair.strip()), when you strip a
commit that's not the tip of the revlog, there may be commits after it in revnum
order that aren't descended from it and don't need to be (and shouldn't be)
stripped. These are "saved" by strip in a bundle, and that bundle is reapplied
after truncating the relevant revlogs.

### The problem

Remotefilelog generally avoids being involved at all in strip. Currently, that
includes even providing file contents to this backup bundle. This can cause the
linknode to point to a changeset that is no longer in the repository.

Example:

```
@  3 df91f74b871e
|
| x  2 70494d7ec5ef
|/
| x  1 1e423846dde0
|/
o  0 b292c1e3311f
```

Commits 1, 2, and 3 are related via obsolescence, and are description-only
changes. The linknode for the file in these commits changed each time we updated
the description, so it's currently df91f7. If I strip commits 1 and 3, however,
the linknode *remains* df91f7, which no longer exists in the repository. Commit
70494d was "saved", stripped, and then reapplied, so it is in the repository (as
revision 1 instead of 2 now), and was unobsoleted since the obsmarker was
stripped as well. The linknode for the file should point to 70494d, the most
recent commit that is in the repository that modified the file.

Remotefilelog has some logic to handle broken linknodes, but it can be slow. We
have actually disabled it internally because it's too slow for our purposes.

Differential Revision: https://phab.mercurial-scm.org/D10319

init

  $ hg init t
  $ cd t

setup

  $ echo r1 > r1
  $ hg ci -qAmr1 -d'0 0'
  $ mkdir directory
  $ echo r2 > directory/r2
  $ hg ci -qAmr2 -d'1 0'
  $ echo 'ignored' > .hgignore
  $ hg ci -qAmr3 -d'2 0'

purge without the extension

  $ hg st
  $ touch foo
  $ hg purge
  permanently delete 1 unkown files? (yN) n
  abort: removal cancelled
  [250]
  $ hg st
  ? foo
  $ hg purge --no-confirm
  $ hg st

now enabling the extension

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > purge =
  > EOF

delete an empty directory

  $ mkdir empty_dir
  $ hg purge -p -v
  empty_dir
  $ hg purge --confirm
  permanently delete at least 1 empty directories? (yN) n
  abort: removal cancelled
  [250]
  $ hg purge -v
  removing directory empty_dir
  $ ls -A
  .hg
  .hgignore
  directory
  r1

delete an untracked directory

  $ mkdir untracked_dir
  $ touch untracked_dir/untracked_file1
  $ touch untracked_dir/untracked_file2
  $ hg purge -p
  untracked_dir/untracked_file1
  untracked_dir/untracked_file2
  $ hg purge -v
  removing file untracked_dir/untracked_file1
  removing file untracked_dir/untracked_file2
  removing directory untracked_dir
  $ ls -A
  .hg
  .hgignore
  directory
  r1

delete an untracked file

  $ touch untracked_file
  $ touch untracked_file_readonly
  $ "$PYTHON" <<EOF
  > import os
  > import stat
  > f = 'untracked_file_readonly'
  > os.chmod(f, stat.S_IMODE(os.stat(f).st_mode) & ~stat.S_IWRITE)
  > EOF
  $ hg purge -p
  untracked_file
  untracked_file_readonly
  $ hg purge --confirm
  permanently delete 2 unkown files? (yN) n
  abort: removal cancelled
  [250]
  $ hg purge -v
  removing file untracked_file
  removing file untracked_file_readonly
  $ ls -A
  .hg
  .hgignore
  directory
  r1

delete an untracked file in a tracked directory

  $ touch directory/untracked_file
  $ hg purge -p
  directory/untracked_file
  $ hg purge -v
  removing file directory/untracked_file
  $ ls -A
  .hg
  .hgignore
  directory
  r1

delete nested directories

  $ mkdir -p untracked_directory/nested_directory
  $ hg purge -p
  untracked_directory/nested_directory
  $ hg purge -v
  removing directory untracked_directory/nested_directory
  removing directory untracked_directory
  $ ls -A
  .hg
  .hgignore
  directory
  r1

delete nested directories from a subdir

  $ mkdir -p untracked_directory/nested_directory
  $ cd directory
  $ hg purge -p
  untracked_directory/nested_directory
  $ hg purge -v
  removing directory untracked_directory/nested_directory
  removing directory untracked_directory
  $ cd ..
  $ ls -A
  .hg
  .hgignore
  directory
  r1

delete only part of the tree

  $ mkdir -p untracked_directory/nested_directory
  $ touch directory/untracked_file
  $ cd directory
  $ hg purge -p ../untracked_directory
  untracked_directory/nested_directory
  $ hg purge --confirm
  permanently delete 1 unkown files? (yN) n
  abort: removal cancelled
  [250]
  $ hg purge -v ../untracked_directory
  removing directory untracked_directory/nested_directory
  removing directory untracked_directory
  $ cd ..
  $ ls -A
  .hg
  .hgignore
  directory
  r1
  $ ls directory/untracked_file
  directory/untracked_file
  $ rm directory/untracked_file

skip ignored files if -i or --all not specified

  $ touch ignored
  $ hg purge -p
  $ hg purge --confirm
  $ hg purge -v
  $ touch untracked_file
  $ ls
  directory
  ignored
  r1
  untracked_file
  $ hg purge -p -i
  ignored
  $ hg purge --confirm -i
  permanently delete 1 ignored files? (yN) n
  abort: removal cancelled
  [250]
  $ hg purge -v -i
  removing file ignored
  $ ls -A
  .hg
  .hgignore
  directory
  r1
  untracked_file
  $ touch ignored
  $ hg purge -p --all
  ignored
  untracked_file
  $ hg purge --confirm --all
  permanently delete 1 unkown and 1 ignored files? (yN) n
  abort: removal cancelled
  [250]
  $ hg purge -v --all
  removing file ignored
  removing file untracked_file
  $ ls
  directory
  r1

abort with missing files until we support name mangling filesystems

  $ touch untracked_file
  $ rm r1

hide error messages to avoid changing the output when the text changes

  $ hg purge -p 2> /dev/null
  untracked_file
  $ hg st
  ! r1
  ? untracked_file

  $ hg purge -p
  untracked_file
  $ hg purge -v 2> /dev/null
  removing file untracked_file
  $ hg st
  ! r1

  $ hg purge -v
  $ hg revert --all --quiet
  $ hg st -a

tracked file in ignored directory (issue621)

  $ echo directory >> .hgignore
  $ hg ci -m 'ignore directory'
  $ touch untracked_file
  $ hg purge -p
  untracked_file
  $ hg purge -v
  removing file untracked_file

skip excluded files

  $ touch excluded_file
  $ hg purge -p -X excluded_file
  $ hg purge -v -X excluded_file
  $ ls -A
  .hg
  .hgignore
  directory
  excluded_file
  r1
  $ rm excluded_file

skip files in excluded dirs

  $ mkdir excluded_dir
  $ touch excluded_dir/file
  $ hg purge -p -X excluded_dir
  $ hg purge -v -X excluded_dir
  $ ls -A
  .hg
  .hgignore
  directory
  excluded_dir
  r1
  $ ls excluded_dir
  file
  $ rm -R excluded_dir

skip excluded empty dirs

  $ mkdir excluded_dir
  $ hg purge -p -X excluded_dir
  $ hg purge -v -X excluded_dir
  $ ls -A
  .hg
  .hgignore
  directory
  excluded_dir
  r1
  $ rmdir excluded_dir

skip patterns

  $ mkdir .svn
  $ touch .svn/foo
  $ mkdir directory/.svn
  $ touch directory/.svn/foo
  $ hg purge -p -X .svn -X '*/.svn'
  $ hg purge -p -X re:.*.svn

  $ rm -R .svn directory r1

only remove files

  $ mkdir -p empty_dir dir
  $ touch untracked_file dir/untracked_file
  $ hg purge -p --files
  dir/untracked_file
  untracked_file
  $ hg purge -v --files
  removing file dir/untracked_file
  removing file untracked_file
  $ ls -A
  .hg
  .hgignore
  dir
  empty_dir
  $ ls dir

only remove dirs

  $ mkdir -p empty_dir dir
  $ touch untracked_file dir/untracked_file
  $ hg purge -p --dirs
  empty_dir
  $ hg purge -v --dirs
  removing directory empty_dir
  $ ls -A
  .hg
  .hgignore
  dir
  untracked_file
  $ ls dir
  untracked_file

remove both files and dirs

  $ mkdir -p empty_dir dir
  $ touch untracked_file dir/untracked_file
  $ hg purge -p --files --dirs
  dir/untracked_file
  untracked_file
  empty_dir
  $ hg purge -v --files --dirs
  removing file dir/untracked_file
  removing file untracked_file
  removing directory empty_dir
  removing directory dir
  $ ls -A
  .hg
  .hgignore

  $ cd ..