tests/test-narrow-clone-stream.t

dirstate-tree: Add tree traversal/iteration

Like Python’s, Rust’s iterators are "external" in that they are driven
by a caller who calls a `next` method. This is as opposed to "internal"
iterators who drive themselves and call a callback for each item.

Writing an internal iterator traversing a tree is easy with recursion,
but internal iterators cannot rely on the call stack in that way,
they must save in an explicit object all state that they need to be
preserved across two `next` calls.

This algorithm uses a `Vec` as a stack that contains what would be
local variables on the call stack if we could use recursion.

Differential Revision: https://phab.mercurial-scm.org/D10370

#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
  [100]

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 -A
  .hg
  $ 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
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  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