view tests/test-rebase-mq-skip.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.

This emulates the effects of an hg pull --rebase in which the remote repo
already has one local mq patch

  $ cat >> $HGRCPATH <<EOF
  > [format]
  > usegeneraldelta=yes
  > [extensions]
  > rebase=
  > mq=
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}: '{desc}' tags: {tags}\n"
  > EOF


  $ hg init a
  $ cd a
  $ hg qinit -c

  $ echo c1 > c1
  $ hg add c1
  $ hg ci -m C1

  $ echo r1 > r1
  $ hg add r1
  $ hg ci -m R1

  $ hg up -q 0

  $ hg qnew p0.patch -d '1 0'
  $ echo p0 > p0
  $ hg add p0
  $ hg qref -m P0

  $ hg qnew p1.patch -d '2 0'
  $ echo p1 > p1
  $ hg add p1
  $ hg qref -m P1

  $ hg export qtip > p1.patch

  $ hg up -q -C 1

  $ hg import p1.patch
  applying p1.patch

  $ rm p1.patch

  $ hg up -q -C qtip

  $ hg rebase -v
  rebasing 2:13a46ce44f60 "P0" (p0.patch qbase)
  resolving manifests
  removing p0
  getting r1
  resolving manifests
  getting p0
  committing files:
  p0
  committing manifest
  committing changelog
  rebasing 3:148775c71080 "P1" (p1.patch qtip)
  resolving manifests
  note: rebase of 3:148775c71080 created no changes to commit
  rebase merging completed
  updating mq patch p0.patch to 5:9ecc820b1737
  $TESTTMP/a/.hg/patches/p0.patch (glob)
  2 changesets found
  uncompressed size of bundle content:
       348 (changelog)
       324 (manifests)
       129  p0
       129  p1
  saved backup bundle to $TESTTMP/a/.hg/strip-backup/13a46ce44f60-5da6ecfb-backup.hg (glob)
  2 changesets found
  uncompressed size of bundle content:
       403 (changelog)
       324 (manifests)
       129  p0
       129  p1
  adding branch
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  rebase completed
  1 revisions have been skipped

  $ hg tglog
  @  3: 'P0' tags: p0.patch qbase qtip tip
  |
  o  2: 'P1' tags: qparent
  |
  o  1: 'R1' tags:
  |
  o  0: 'C1' tags:
  
  $ cd ..


  $ hg init b
  $ cd b
  $ hg qinit -c

  $ for i in r0 r1 r2 r3 r4 r5 r6;
  > do
  >     echo $i > $i
  >     hg ci -Am $i
  > done
  adding r0
  adding r1
  adding r2
  adding r3
  adding r4
  adding r5
  adding r6

  $ hg qimport -r 1:tip

  $ hg up -q 0

  $ for i in r1 r3 r7 r8;
  > do
  >     echo $i > $i
  >     hg ci -Am branch2-$i
  > done
  adding r1
  created new head
  adding r3
  adding r7
  adding r8

  $ echo somethingelse > r4
  $ hg ci -Am branch2-r4
  adding r4

  $ echo r6 > r6
  $ hg ci -Am branch2-r6
  adding r6

  $ hg up -q qtip

  $ HGMERGE=internal:fail hg rebase
  rebasing 1:b4bffa6e4776 "r1" (qbase r1)
  note: rebase of 1:b4bffa6e4776 created no changes to commit
  rebasing 2:c0fd129beb01 "r2" (r2)
  rebasing 3:6ff5b8feed8e "r3" (r3)
  note: rebase of 3:6ff5b8feed8e created no changes to commit
  rebasing 4:094320fec554 "r4" (r4)
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

  $ HGMERGE=internal:local hg resolve --all
  (no more unresolved files)
  continue: hg rebase --continue

  $ hg rebase --continue
  already rebased 1:b4bffa6e4776 "r1" (qbase r1) as 057f55ff8f44
  already rebased 2:c0fd129beb01 "r2" (r2) as 1660ab13ce9a
  already rebased 3:6ff5b8feed8e "r3" (r3) as 1660ab13ce9a
  rebasing 4:094320fec554 "r4" (r4)
  note: rebase of 4:094320fec554 created no changes to commit
  rebasing 5:681a378595ba "r5" (r5)
  rebasing 6:512a1f24768b "r6" (qtip r6)
  note: rebase of 6:512a1f24768b created no changes to commit
  saved backup bundle to $TESTTMP/b/.hg/strip-backup/b4bffa6e4776-b9bfb84d-backup.hg (glob)

  $ hg tglog
  @  8: 'r5' tags: qtip r5 tip
  |
  o  7: 'r2' tags: qbase r2
  |
  o  6: 'branch2-r6' tags: qparent
  |
  o  5: 'branch2-r4' tags:
  |
  o  4: 'branch2-r8' tags:
  |
  o  3: 'branch2-r7' tags:
  |
  o  2: 'branch2-r3' tags:
  |
  o  1: 'branch2-r1' tags:
  |
  o  0: 'r0' tags:
  

  $ cd ..