tests/test-subrepo-relative-path.t

bundle2: extract logic for seeking bundle2 part into own class

Currently, unbundlepart classes support bi-directional seeking.
Most consumers of unbundlepart only ever seek forward - typically
as part of moving to the end of the bundle part so they can move
on to the next one. But regardless of the actual usage of the
part, instances maintain an index mapping offsets within the
underlying raw payload to offsets within the decoded payload.

Maintaining the mapping of offset data can be expensive in terms of
memory use. Furthermore, many bundle2 consumers don't have access
to an underlying seekable stream. This includes all compressed
bundles. So maintaining offset data when the underlying stream
can't be seeked anyway is wasteful. And since many bundle2 streams
can't be seeked, it seems like a bad idea to expose a seek API
in bundle2 parts by default. If you provide them, people will
attempt to use them.

Seekable bundle2 parts should be the exception, not the rule. This
commit starts the process dividing unbundlepart into 2 classes: a
base class that supports linear, one-time reads and a child class
that supports bi-directional seeking. In this first commit, we
split various methods and attributes out into a new
"seekableunbundlepart" class. Previous instantiators of "unbundlepart"
now instantiate "seekableunbundlepart." This preserves backwards
compatibility. The coupling between the classes is still tight:
"unbundlepart" cannot be used on its own. This will be addressed
in subsequent commits.

Differential Revision: https://phab.mercurial-scm.org/D1386

#require killdaemons

Preparing the subrepository 'sub'

  $ hg init sub
  $ echo sub > sub/sub
  $ hg add -R sub
  adding sub/sub (glob)
  $ hg commit -R sub -m "sub import"

Preparing the 'main' repo which depends on the subrepo 'sub'

  $ hg init main
  $ echo main > main/main
  $ echo "sub = ../sub" > main/.hgsub
  $ hg clone sub main/sub
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg add -R main
  adding main/.hgsub (glob)
  adding main/main (glob)
  $ hg commit -R main -m "main import"

Cleaning both repositories, just as a clone -U

  $ hg up -C -R sub null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg up -C -R main null
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ rm -rf main/sub

hide outer repo
  $ hg init

Serving them both using hgweb

  $ printf '[paths]\n/main = main\nsub = sub\n' > webdir.conf
  $ hg serve --webdir-conf webdir.conf -a localhost -p $HGPORT \
  >    -A /dev/null -E /dev/null --pid-file hg.pid -d
  $ cat hg.pid >> $DAEMON_PIDS

Clone main from hgweb

  $ hg clone "http://localhost:$HGPORT/main" cloned
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  new changesets fdfeeb3e979e
  updating to branch default
  cloning subrepo sub from http://localhost:$HGPORT/sub
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 863c1745b441
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

Checking cloned repo ids

  $ hg id -R cloned
  fdfeeb3e979e tip
  $ hg id -R cloned/sub
  863c1745b441 tip

subrepo debug for 'main' clone

  $ hg debugsub -R cloned
  path sub
   source   ../sub
   revision 863c1745b441bd97a8c4a096e87793073f4fb215

  $ killdaemons.py

subrepo paths with ssh urls

  $ hg clone -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" ssh://user@dummy/cloned sshclone
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  new changesets fdfeeb3e979e
  updating to branch default
  cloning subrepo sub from ssh://user@dummy/sub
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 863c1745b441
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg -R sshclone push -e "\"$PYTHON\" \"$TESTDIR/dummyssh\"" ssh://user@dummy/`pwd`/cloned
  pushing to ssh://user@dummy/$TESTTMP/cloned
  pushing subrepo sub to ssh://user@dummy/$TESTTMP/sub
  searching for changes
  no changes found
  searching for changes
  no changes found
  [1]

  $ cat dummylog
  Got arguments 1:user@dummy 2:hg -R cloned serve --stdio
  Got arguments 1:user@dummy 2:hg -R sub serve --stdio
  Got arguments 1:user@dummy 2:hg -R $TESTTMP/cloned serve --stdio
  Got arguments 1:user@dummy 2:hg -R $TESTTMP/sub serve --stdio