view tests/test-strip-cross.t @ 33289:abd7dedbaa36

sparse: vendor Facebook-developed extension

Facebook has developed an extension to enable "sparse" checkouts -
a working directory with a subset of files. This feature is a critical
component in enabling repositories to scale to infinite number of
files while retaining reasonable performance. It's worth noting
that sparse checkout is only one possible solution to this problem:
another is virtual filesystems that realize files on first access.
But given that virtual filesystems may not be accessible to all
users, sparse checkout is necessary as a fallback.

Per mailing list discussion at
https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-March/095868.html
we want to add sparse checkout to the Mercurial distribution via
roughly the following mechanism:

1. Vendor extension as-is with minimal modifications (this patch)
2. Refactor extension so it is more clearly experimental and inline
   with Mercurial practices
3. Move code from extension into core where possible
4. Drop experimental labeling and/or move feature into core
   after sign-off from narrow clone feature owners

This commit essentially copies the sparse extension and tests
from revision 71e0a2aeca92a4078fe1b8c76e32c88ff1929737 of the
https://bitbucket.org/facebook/hg-experimental repository.

A list of modifications made as part of vendoring is as follows:

* "EXPERIMENTAL" added to module docstring
* Imports were changed to match Mercurial style conventions
* "testedwith" value was updated to core Mercurial special value and
  comment boilerplate was inserted
* A "clone_sparse" function was renamed to "clonesparse" to appease
  the style checker
* Paths to the sparse extension in tests reflect built-in location
* test-sparse-extensions.t was renamed to test-sparse-fsmonitor.t
  and references to "simplecache" were removed. The test always skips
  because it isn't trivial to run it given the way we currently run
  fsmonitor tests
* A double empty line was removed from test-sparse-profiles.t

There are aspects of the added code that are obviously not ideal.
The goal is to make a minimal number of modifications as part of
the vendoring to make it easier to track changes from the original
implementation. Refactoring will occur in subsequent patches.

test stripping of filelogs where the linkrev doesn't always increase

  $ echo '[extensions]' >> $HGRCPATH
  $ echo 'strip =' >> $HGRCPATH
  $ hg init orig
  $ cd orig
  $ commit()
  > {
  >     hg up -qC null
  >     count=1
  >     for i in "$@"; do
  >         for f in $i; do
  >             echo $count > $f
  >         done
  >         count=`expr $count + 1`
  >     done
  >     hg commit -qAm "$*"
  > }

2 1 0 2 0 1 2

  $ commit '201 210'
  $ commit '102 120' '210'
  $ commit '021'
  $ commit '201' '021 120'
  $ commit '012 021' '102 201' '120 210'
  $ commit 'manifest-file'
  $ commit '102 120' '012 210' '021 201'
  $ commit '201 210' '021 120' '012 102'
  $ HGUSER=another-user; export HGUSER
  $ commit 'manifest-file'
  $ commit '012' 'manifest-file'
  $ cd ..
  $ hg clone -q -U -r -1 -r -2 -r -3 -r -4 -r -6 orig crossed
  $ cd crossed
  $ hg debugindex --manifest
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0     112  .....       0 6f105cbb914d 000000000000 000000000000 (re)
       1       112      56  .....       3 1b55917b3699 000000000000 000000000000 (re)
       2       168     123  .....       1 8f3d04e263e5 000000000000 000000000000 (re)
       3       291     122  .....       2 f0ef8726ac4f 000000000000 000000000000 (re)
       4       413      87  .....       4 0b76e38b4070 000000000000 000000000000 (re)

  $ for i in 012 021 102 120 201 210 manifest-file; do
  >     echo $i
  >     hg debugindex $i
  >     echo
  > done
  012
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       1 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       2 2661d26c6496 000000000000 000000000000 (re)
  
  021
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       2 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       1 2661d26c6496 000000000000 000000000000 (re)
  
  102
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       1 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       0 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       2 2661d26c6496 000000000000 000000000000 (re)
  
  120
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       1 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       2 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       0 2661d26c6496 000000000000 000000000000 (re)
  
  201
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       2 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       0 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       1 2661d26c6496 000000000000 000000000000 (re)
  
  210
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       2 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       1 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       0 2661d26c6496 000000000000 000000000000 (re)
  
  manifest-file
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       3 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       4 5d9299349fc0 000000000000 000000000000 (re)
  
  $ cd ..
  $ for i in 0 1 2 3 4; do
  >     hg clone -q -U --pull crossed $i
  >     echo "% Trying to strip revision $i"
  >     hg --cwd $i strip $i
  >     echo "% Verifying"
  >     hg --cwd $i verify
  >     echo
  > done
  % Trying to strip revision 0
  saved backup bundle to $TESTTMP/0/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 15 total revisions
  
  % Trying to strip revision 1
  saved backup bundle to $TESTTMP/1/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 14 total revisions
  
  % Trying to strip revision 2
  saved backup bundle to $TESTTMP/2/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 14 total revisions
  
  % Trying to strip revision 3
  saved backup bundle to $TESTTMP/3/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 19 total revisions
  
  % Trying to strip revision 4
  saved backup bundle to $TESTTMP/4/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 19 total revisions