tests/test-remotefilelog-partial-shallow.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

#require no-windows

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

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > foo
  $ echo y > bar
  $ hg commit -qAm one

  $ cd ..

# partial shallow clone

  $ hg clone --shallow ssh://user@dummy/master shallow --noupdate --config remotefilelog.includepattern=foo
  streaming all changes
  3 files to transfer, 336 bytes of data (no-zstd !)
  transferred 336 bytes in * seconds (* */sec) (glob) (no-zstd !)
  3 files to transfer, 338 bytes of data (zstd !)
  transferred 338 bytes in * seconds (* */sec) (glob) (zstd !)
  searching for changes
  no changes found
  $ cat >> shallow/.hg/hgrc <<EOF
  > [remotefilelog]
  > cachepath=$PWD/hgcache
  > debug=True
  > includepattern=foo
  > reponame = master
  > [extensions]
  > remotefilelog=
  > EOF
  $ ls shallow/.hg/store/data
  bar.i

# update partial clone

  $ cd shallow
  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cat foo
  x
  $ cat bar
  y
  $ cd ..

# pull partial clone

  $ cd master
  $ echo a >> foo
  $ echo b >> bar
  $ hg commit -qm two
  $ cd ../shallow
  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets a9688f18cb91
  (run 'hg update' to get a working copy)
  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cat foo
  x
  a
  $ cat bar
  y
  b

  $ cd ..