tests/test-remotefilelog-bundles.t

rust: switch hg-core and hg-cpython to rust 2018 edition

Many interesting changes have happened in Rust since the Oxidation Plan was
introduced, like the 2018 edition and procedural macros:

    - Opting in to the 2018 edition is a clear benefit in terms of future
      proofing, new (nice to have) syntactical sugar notwithstanding. It
      also has a new non-lexical, non-AST based borrow checker that has
      fewer bugs(!) and allows us to write correct code that in some cases
      would have been rejected by the old one.
    - Procedural macros allow us to use the PyO3 crate which maintainers have
      expressed the clear goal of compiling on stable, which would help in
      code maintainability compared to rust-cpython.

In this patch are the following changes:
    - Removing most `extern crate` uses
    - Updating `use` clauses (`crate` keyword, nested `use`)
    - Removing `mod.rs` in favor of an aptly named module file

Like discussed in the mailing list (
https://www.mercurial-scm.org/pipermail/mercurial-devel/2019-July/132316.html
), until Rust integration in Mercurial is considered to be out of the
experimental phase, the maximum version of Rust allowed is whatever the latest
version Debian packages.

Differential Revision: https://phab.mercurial-scm.org/D6597

#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
  $ echo y >> x
  $ hg commit -qAm y
  $ echo z >> x
  $ hg commit -qAm z

  $ 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

Unbundling a shallow bundle

  $ hg strip -r 66ee28d0328c
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/66ee28d0328c-3d7aafd1-backup.hg (glob)
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ hg unbundle .hg/strip-backup/66ee28d0328c-3d7aafd1-backup.hg
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 0 changes to 0 files
  new changesets 66ee28d0328c:16db62c5946f
  (run 'hg update' to get a working copy)

Unbundling a full bundle

  $ hg -R ../master bundle -r 66ee28d0328c:: --base "66ee28d0328c^" ../fullbundle.hg
  2 changesets found
  $ hg strip -r 66ee28d0328c
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/66ee28d0328c-3d7aafd1-backup.hg (glob)
  $ hg unbundle ../fullbundle.hg
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 66ee28d0328c:16db62c5946f (2 drafts)
  (run 'hg update' to get a working copy)

Pulling from a shallow bundle

  $ hg strip -r 66ee28d0328c
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/66ee28d0328c-3d7aafd1-backup.hg (glob)
  $ hg pull -r 66ee28d0328c .hg/strip-backup/66ee28d0328c-3d7aafd1-backup.hg
  pulling from .hg/strip-backup/66ee28d0328c-3d7aafd1-backup.hg
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets 66ee28d0328c (1 drafts)
  (run 'hg update' to get a working copy)

Pulling from a full bundle

  $ hg strip -r 66ee28d0328c
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/66ee28d0328c-b6ee89e7-backup.hg (glob)
  $ hg pull -r 66ee28d0328c ../fullbundle.hg
  pulling from ../fullbundle.hg
  searching for changes
  abort: cannot pull from full bundles
  (use `hg unbundle` instead)
  [255]