tests/test-convert-bzr-ghosts.t

rust-cpython: mark unsafe functions as such

It wasn't trivial to fix leak_immutable() to be safe since we have to
allow immutable operations (e.g. iter()) on the leaked reference. So
let's mark it unsafe for now. Callers must take care of the returned
object to guarantee the memory safety.

I'll revisit this later. I think $leaked<T: 'static> could have a function
that converts itself into $leaked<U: 'static> with a given FnOnce(&T) -> &U,
where T is $inner_struct, and U is $iterator_type for example.

#require bzr

  $ . "$TESTDIR/bzr-definitions"
  $ cat > ghostcreator.py <<EOF
  > import sys
  > from bzrlib import workingtree
  > wt = workingtree.WorkingTree.open('.')
  > 
  > message, ghostrev = sys.argv[1:]
  > wt.set_parent_ids(wt.get_parent_ids() + [ghostrev])
  > wt.commit(message)
  > EOF

ghost revisions

  $ mkdir test-ghost-revisions
  $ cd test-ghost-revisions
  $ bzr init -q source
  $ cd source
  $ echo content > somefile
  $ bzr add -q somefile
  $ bzr commit -q -m 'Initial layout setup'
  $ echo morecontent >> somefile
  $ "$PYTHON" ../../ghostcreator.py 'Commit with ghost revision' ghostrev
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  1 Initial layout setup
  0 Commit with ghost revision
  $ glog -R source-hg
  o  1@source "Commit with ghost revision" files+: [], files-: [], files: [somefile]
  |
  o  0@source "Initial layout setup" files+: [somefile], files-: [], files: []
  

  $ cd ..