remotefilelog: import pruned-down remotefilelog extension from hg-experimental This is remotefilelog as of my recent patches for compatibility with current tip of hg, minus support for old versions of Mercurial and some FB-specific features like their treemanifest extension and fetching linkrev data from a patched phabricator. The file extutil.py moved from hgext3rd to remotefilelog. This is not yet ready to be landed, consider it a preview for now. Planned changes include: * replace lz4 with zstd * rename some capabilities, requirements and wireproto commands to mark them as experimental * consolidate bits of shallowutil with related functions (eg readfile) I'm certainly open to other (small) changes, but my rough mission is to land this largely as-is so we can use it as a model of the functionality we need going forward for lazy-fetching of file contents from a server. # no-check-commit because of a few foo_bar functions Differential Revision: https://phab.mercurial-scm.org/D4782

  $ PYTHONPATH=$TESTDIR/..:$PYTHONPATH
  $ export PYTHONPATH

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

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

  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow -q
  3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
  $ cd shallow

Verify error message when noc achepath specified
  $ hg up -q null
  $ cp $HGRCPATH $HGRCPATH.bak
  $ grep -v cachepath < $HGRCPATH.bak > tmp
  $ mv tmp $HGRCPATH
  $ hg up tip
  abort: could not find config option remotefilelog.cachepath
  [255]
  $ mv $HGRCPATH.bak $HGRCPATH

Verify error message when no fallback specified

  $ hg up -q null
  $ rm .hg/hgrc
  $ clearcache
  $ hg up tip
  3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
  abort: no remotefilelog server configured - is your .hg/hgrc trusted?
  [255]