tests/test-remotefilelog-strip.t

urlutil: add a `get_clone_path` function

We add a new function with a semantic focussed on `clone` operation (so without
an existing repository). I am not certain the return type is the best, but this
is what we need for now. Once all caller are migrated we might start thinking
about that the API should be. For now that will do.

Differential Revision: https://phab.mercurial-scm.org/D10401

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ hg commit -qAm x

  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow -q
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cd shallow

  $ cat >> $TESTTMP/get_file_linknode.py <<EOF
  > from mercurial import node, registrar, scmutil
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'debug-file-linknode', [(b'r', b'rev', b'.', b'rev')], b'hg debug-file-linknode FILE')
  > def debug_file_linknode(ui, repo, file, **opts):
  >   rflctx = scmutil.revsingle(repo.unfiltered(), opts['rev']).filectx(file)
  >   ui.status(b'%s\n' % node.hex(rflctx.ancestormap()[rflctx._filenode][2]))
  > EOF

  $ cat >> .hg/hgrc <<EOF
  > [ui]
  > interactive=1
  > [extensions]
  > strip=
  > get_file_linknode=$TESTTMP/get_file_linknode.py
  > [experimental]
  > evolution=createmarkers,allowunstable
  > EOF
  $ echo a > a
  $ hg commit -qAm msg1
  $ hg commit --amend 're:^$' -m msg2
  $ hg commit --amend 're:^$' -m msg3
  $ hg --hidden log -G -T '{rev} {node|short}'
  @  3 df91f74b871e
  |
  | x  2 70494d7ec5ef
  |/
  | x  1 1e423846dde0
  |/
  o  0 b292c1e3311f
  
  $ hg debug-file-linknode -r 70494d a
  df91f74b871e064c89afa1fe9e2f66afa2c125df
  $ hg --hidden strip -r 1 3
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/df91f74b871e-c94d67be-backup.hg

  $ hg --hidden log -G -T '{rev} {node|short}'
  o  1 70494d7ec5ef
  |
  @  0 b292c1e3311f
  
Demonstrate that the linknode points to a commit that is actually in the repo
after the strip operation. Otherwise remotefilelog has to search every commit in
the repository looking for a valid linkrev every time it's queried, such as
during push.
  $ hg debug-file-linknode -r 70494d a
  70494d7ec5ef6cd3cd6939a9fd2812f9956bf553