tests/test-remotefilelog-strip.t

revlog: move the details of revlog "v2" index inside revlog.utils.constants

the revlog module is quite large and this kind of format information would handy
for other module. So let us start to gather this information about the format in
a more appropriate place.

We update various reference to this information to use the new "source of truth"
in the process.

Differential Revision: https://phab.mercurial-scm.org/D10305

#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