tests/test-mq-pull-from-bundle.t

scmutil: add file object wrapper class to check ambiguity at closing

In Mercurial source tree, opening a file in "a"/"a+" mode like below
doesn't specify atomictemp=True for vfs, and this avoids file stat
ambiguity check by atomictempfile.

  - writing changes out in revlog layer uses "a+" mode
  - truncation in repair.strip() uses "a" mode
  - truncation in transaction._playback() uses "a" mode

If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).

  1. append data to revlog-style file (and close transaction)
  2. discard appended data by truncation (strip or rollback)
  3. append same size but different data to revlog-style file again

Therefore, cache validation doesn't work after (3) as expected.

This patch adds file object wrapper class checkambigatclosing to check
(and get rid of) ambiguity at closing. It is used by vfs in subsequent
patch.

This is a part of ExactCacheValidationPlan.

    https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

BTW, checkambigatclosing is tested in test-filecache.py, even though
it doesn't use filecache itself, because filecache assumes that file
stat ambiguity never occurs (and there is no another test-*.py related
to filecache).

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > mq=
  > [alias]
  > tlog = log --template "{rev}: {desc}\\n"
  > theads = heads --template "{rev}: {desc}\\n"
  > tincoming = incoming --template "{rev}: {desc}\\n"
  > EOF

Setup main:

  $ hg init base
  $ cd base
  $ echo "One" > one
  $ hg add
  adding one
  $ hg ci -m "main: one added"
  $ echo "++" >> one
  $ hg ci -m "main: one updated"

Bundle main:

  $ hg bundle --base=null ../main.hg
  2 changesets found

  $ cd ..

Incoming to fresh repo:

  $ hg init fresh

  $ hg -R fresh tincoming main.hg
  comparing with main.hg
  0: main: one added
  1: main: one updated
  $ test -f ./fresh/.hg/hg-bundle* && echo 'temp. bundle file remained' || true

  $ hg -R fresh tincoming bundle:fresh+main.hg
  comparing with bundle:fresh+main.hg
  0: main: one added
  1: main: one updated


Setup queue:

  $ cd base
  $ hg qinit -c
  $ hg qnew -m "patch: two added" two.patch
  $ echo two > two
  $ hg add
  adding two
  $ hg qrefresh
  $ hg qcommit -m "queue: two.patch added"
  $ hg qpop -a
  popping two.patch
  patch queue now empty

Bundle queue:

  $ hg -R .hg/patches bundle --base=null ../queue.hgq
  1 changesets found
  $ test -f ./fresh/.hg/hg-bundle* && echo 'temp. bundle file remained' || true

  $ cd ..


Clone base:

  $ hg clone base copy
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd copy
  $ hg qinit -c

Incoming queue bundle:

  $ hg -R .hg/patches tincoming ../queue.hgq
  comparing with ../queue.hgq
  0: queue: two.patch added
  $ test -f .hg/hg-bundle* && echo 'temp. bundle file remained' || true

Pull queue bundle:

  $ hg -R .hg/patches pull --update ../queue.hgq
  pulling from ../queue.hgq
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  merging series
  2 files updated, 1 files merged, 0 files removed, 0 files unresolved
  $ test -f .hg/patches/hg-bundle* && echo 'temp. bundle file remained' || true

  $ hg -R .hg/patches theads
  0: queue: two.patch added

  $ hg -R .hg/patches tlog
  0: queue: two.patch added

  $ hg qseries
  two.patch

  $ cd ..


Clone base again:

  $ hg clone base copy2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd copy2
  $ hg qinit -c

Unbundle queue bundle:

  $ hg -R .hg/patches unbundle --update ../queue.hgq
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  merging series
  2 files updated, 1 files merged, 0 files removed, 0 files unresolved

  $ hg -R .hg/patches theads
  0: queue: two.patch added

  $ hg -R .hg/patches tlog
  0: queue: two.patch added

  $ hg qseries
  two.patch

  $ cd ..