tests/test-convert-identity.t

py: error out if a "skip" character was given with non-dict to util.dirs()

util.dirs() keeps track of the directories in its input collection. If
a "skip" character is given to it, it will assume the input is a
dirstate map and it will skip entries that are in the given "skip"
state. I think this is used only for skipping removed entries ("r") in
the dirtate. The C implementation of util.dirs() errors out if it was
given a skip character and a non-dict was passed. The pure
implementation simply ignored the request skip state. Let's make it
easier to discover bugs here by erroring out in the pure
implementation too. Let's also switch to checking for the dict-ness,
to make the C implementation (since that's clearly been sufficient for
many years). This last change makes test-issue660.t pass on py3 in
pure mode, since the old check was for existence of iteritems(), which
doesn't exist on py3.

Differential Revision: https://phab.mercurial-scm.org/D6669

Testing that convert.hg.preserve-hash=true can be used to make hg
convert from hg repo to hg repo preserve hashes, even if the
computation of the files list in commits change slightly between hg
versions.

  $ cat <<'EOF' >> "$HGRCPATH"
  > [extensions]
  > convert =
  > EOF
  $ cat <<'EOF' > changefileslist.py
  > from mercurial import (changelog, extensions)
  > def wrap(orig, clog, manifest, files, *args, **kwargs):
  >   return orig(clog, manifest, [b"a"], *args, **kwargs)
  > def extsetup(ui):
  >   extensions.wrapfunction(changelog.changelog, 'add', wrap)
  > EOF

  $ hg init repo
  $ cd repo
  $ echo a > a; hg commit -qAm a
  $ echo b > a; hg commit -qAm b
  $ hg up -qr 0; echo c > c; hg commit -qAm c
  $ hg merge -qr 1
  $ hg commit -m_ --config extensions.x=../changefileslist.py
  $ hg log -r . -T '{node|short} {files|json}\n'
  c085bbe93d59 ["a"]

Now that we have a commit with a files list that's not what the
current hg version would create, check that convert either fixes it or
keeps it depending on config:

  $ hg convert -q . ../convert
  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
  b7c4d4bbacd3 []
  $ rm -rf ../convert

  $ hg convert -q . ../convert --config convert.hg.preserve-hash=true
  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
  c085bbe93d59 ["a"]
  $ rm -rf ../convert