tests/test-identify.t

largefiles: optimize update speed by only updating changed largefiles

Historically, during 'hg update', every largefile in the working copy was
hashed (which is a very expensive operation on big files) and any
largefiles that did not have a hash that matched their standin were
updated.

This patch optimizes 'hg update' by keeping track of what standins have
changed between the old and new revisions, and only updating the largefiles
that have changed.  This saves a lot of time by avoiding the unecessary
calculation of a list of sha1 hashes for big files.

With this patch, the time 'hg update' takes to complete is a function of
how many largefiles need to be updated and what their size is.

Performance tests on a repository with about 80 largefiles ranging from
a few MB to about 97 MB are shown below.  The tests show how long it takes
to run 'hg update' with no changes actually being updated.

Mercurial 2.1 release:

$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
0 largefiles updated, 0 removed

real    0m10.045s
user    0m9.367s
sys    0m0.674s

With this patch:

$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved

real    0m0.965s
user    0m0.845s
sys    0m0.115s

The same repsoitory, without the largefiles extension enabled:

$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved

real    0m0.799s
user    0m0.684s
sys    0m0.111s

So before the patch, 'hg update' with no changes was approximately 9.25s
slower with largefiles enabled.  With this patch, it is approximately 0.165s
slower.

  $ "$TESTDIR/hghave" no-outer-repo serve || exit 80

no repo

  $ hg id
  abort: there is no Mercurial repository here (.hg not found)
  [255]

create repo

  $ hg init test
  $ cd test
  $ echo a > a
  $ hg ci -Ama
  adding a

basic id usage

  $ hg id
  cb9a9f314b8b tip
  $ hg id --debug
  cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b tip
  $ hg id -q
  cb9a9f314b8b
  $ hg id -v
  cb9a9f314b8b tip

with options

  $ hg id -r.
  cb9a9f314b8b tip
  $ hg id -n
  0
  $ hg id -t
  tip
  $ hg id -b
  default
  $ hg id -i
  cb9a9f314b8b
  $ hg id -n -t -b -i
  cb9a9f314b8b 0 default tip

with modifications

  $ echo b > a
  $ hg id -n -t -b -i
  cb9a9f314b8b+ 0+ default tip

other local repo

  $ cd ..
  $ hg -R test id
  cb9a9f314b8b+ tip
  $ hg id test
  cb9a9f314b8b+ tip

with remote http repo

  $ cd test
  $ hg serve -p $HGPORT1 -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ hg id http://localhost:$HGPORT1/
  cb9a9f314b8b

remote with rev number?

  $ hg id -n http://localhost:$HGPORT1/
  abort: can't query remote revision number, branch, or tags
  [255]

remote with tags?

  $ hg id -t http://localhost:$HGPORT1/
  abort: can't query remote revision number, branch, or tags
  [255]

remote with branch?

  $ hg id -b http://localhost:$HGPORT1/
  abort: can't query remote revision number, branch, or tags
  [255]

test bookmark support

  $ hg bookmark Y
  $ hg bookmark Z
  $ hg bookmarks
     Y                         0:cb9a9f314b8b
   * Z                         0:cb9a9f314b8b
  $ hg id
  cb9a9f314b8b+ tip Y/Z
  $ hg id --bookmarks
  Y Z

test remote identify with bookmarks

  $ hg id http://localhost:$HGPORT1/
  cb9a9f314b8b Y/Z
  $ hg id --bookmarks http://localhost:$HGPORT1/
  Y Z
  $ hg id -r . http://localhost:$HGPORT1/
  cb9a9f314b8b Y/Z
  $ hg id --bookmarks -r . http://localhost:$HGPORT1/
  Y Z

Make sure we do not obscure unknown requires file entries (issue2649)

  $ echo fake >> .hg/requires
  $ hg id
  abort: unknown repository format: requires features 'fake' (upgrade Mercurial)!
  [255]

  $ cd ..
  $ hg id test
  abort: unknown repository format: requires features 'fake' (upgrade Mercurial)!
  [255]