view tests/test-branch-option.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 branch selection options

  $ hg init branch
  $ cd branch
  $ hg branch a
  marked working directory as branch a
  (branches are permanent and global, did you want a bookmark?)
  $ echo a > foo
  $ hg ci -d '0 0' -Ama
  adding foo
  $ echo a2 > foo
  $ hg ci -d '0 0' -ma2
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch c
  marked working directory as branch c
  $ echo c > foo
  $ hg ci -d '0 0' -mc
  $ hg tag -l z
  $ cd ..
  $ hg clone -r 0 branch branch2
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch a
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd branch2
  $ hg up 0
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch b
  marked working directory as branch b
  $ echo b > foo
  $ hg ci -d '0 0' -mb
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --encoding utf-8 branch æ
  marked working directory as branch \xc3\xa6 (esc)
  $ echo ae1 > foo
  $ hg ci -d '0 0' -mae1
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --encoding utf-8 branch -f æ
  marked working directory as branch \xc3\xa6 (esc)
  $ echo ae2 > foo
  $ hg ci -d '0 0' -mae2
  created new head
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch -f b
  marked working directory as branch b
  $ echo b2 > foo
  $ hg ci -d '0 0' -mb2
  created new head

unknown branch and fallback

  $ hg in -qbz
  abort: unknown branch 'z'!
  [255]
  $ hg in -q ../branch#z
  2:f25d57ab0566
  $ hg out -qbz
  abort: unknown branch 'z'!
  [255]

in rev c branch a

  $ hg in -qr c ../branch#a
  1:dd6e60a716c6
  2:f25d57ab0566
  $ hg in -qr c -b a
  1:dd6e60a716c6
  2:f25d57ab0566

out branch .

  $ hg out -q ../branch#.
  1:b84708d77ab7
  4:65511d0e2b55
  $ hg out -q -b .
  1:b84708d77ab7
  4:65511d0e2b55

out branch . non-ascii

  $ hg --encoding utf-8 up æ
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --encoding latin1 out -q ../branch#.
  2:df5a44224d4e
  3:4f4a5125ca10
  $ hg --encoding latin1 out -q -b .
  2:df5a44224d4e
  3:4f4a5125ca10

clone branch b

  $ cd ..
  $ hg clone branch2#b branch3
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files (+1 heads)
  updating to branch b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -q -R branch3 heads b
  2:65511d0e2b55
  1:b84708d77ab7
  $ hg -q -R branch3 parents
  2:65511d0e2b55
  $ rm -rf branch3

clone rev a branch b

  $ hg clone -r a branch2#b branch3
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files (+1 heads)
  updating to branch a
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -q -R branch3 heads b
  2:65511d0e2b55
  1:b84708d77ab7
  $ hg -q -R branch3 parents
  0:5b65ba7c951d
  $ rm -rf branch3