tests/test-narrow-clone-stream.t

py3: fix curses chunkselector fallback (when diffs are too large) on py3

Previously we showed the message using Exception.message, which is removed in
py3. Since crecordmod.fallbackerror inherits from error.Abort, we can just use
`b'%s' % exception` to print the message. This does not print the hint, but
that's fine - we don't set one. We inherit from error.Abort so that if a
codepath doesn't handle fallback specially, it exits to the terminal with a sane
message instead of an unknown exception error.

Differential Revision: https://phab.mercurial-scm.org/D7912

#testcases tree flat-fncache flat-nofncache

Tests narrow stream clones

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

#if tree
  $ cat << EOF >> $HGRCPATH
  > [experimental]
  > treemanifest = 1
  > EOF
#endif

#if flat-nofncache
  $ cat << EOF >> $HGRCPATH
  > [format]
  > usefncache = 0
  > EOF
#endif

Server setup

  $ hg init master
  $ cd master
  $ mkdir dir
  $ mkdir dir/src
  $ cd dir/src
  $ for x in `$TESTDIR/seq.py 20`; do echo $x > "F$x"; hg add "F$x"; hg commit -m "Commit src $x"; done

  $ cd ..
  $ mkdir tests
  $ cd tests
  $ for x in `$TESTDIR/seq.py 20`; do echo $x > "F$x"; hg add "F$x"; hg commit -m "Commit src $x"; done
  $ cd ../../..

Trying to stream clone when the server does not support it

  $ hg clone --narrow ssh://user@dummy/master narrow --noupdate --include "dir/src/F10" --stream
  streaming all changes
  remote: abort: server does not support narrow stream clones
  abort: pull failed on remote
  [255]

Enable stream clone on the server

  $ echo "[experimental]" >> master/.hg/hgrc
  $ echo "server.stream-narrow-clones=True" >> master/.hg/hgrc

Cloning a specific file when stream clone is supported

  $ hg clone --narrow ssh://user@dummy/master narrow --noupdate --include "dir/src/F10" --stream
  streaming all changes
  * files to transfer, * KB of data (glob)
  transferred * KB in * seconds (* */sec) (glob)

  $ cd narrow
  $ ls
  $ hg tracked
  I path:dir/src/F10

Making sure we have the correct set of requirements

  $ cat .hg/requires
  dotencode (tree !)
  dotencode (flat-fncache !)
  fncache (tree !)
  fncache (flat-fncache !)
  generaldelta
  narrowhg-experimental
  revlogv1
  sparserevlog
  store
  treemanifest (tree !)

Making sure store has the required files

  $ ls .hg/store/
  00changelog.i
  00manifest.i
  data
  fncache (tree !)
  fncache (flat-fncache !)
  meta (tree !)
  narrowspec
  undo
  undo.backupfiles
  undo.narrowspec
  undo.phaseroots

Checking that repository has all the required data and not broken

  $ hg verify
  checking changesets
  checking manifests
  checking directory manifests (tree !)
  crosschecking files in changesets and manifests
  checking files
  checked 40 changesets with 1 changes to 1 files