view tests/test-debugbuilddag.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.

plain

  $ hg init
  $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' \
  > --config extensions.progress= --config progress.assume-tty=1 \
  > --config progress.delay=0 --config progress.refresh=0 \
  > --config progress.format=topic,bar,number \
  > --config progress.width=60
  \r (no-eol) (esc)
  building [                                          ]  0/12\r (no-eol) (esc)
  building [                                          ]  0/12\r (no-eol) (esc)
  building [==>                                       ]  1/12\r (no-eol) (esc)
  building [==>                                       ]  1/12\r (no-eol) (esc)
  building [======>                                   ]  2/12\r (no-eol) (esc)
  building [=========>                                ]  3/12\r (no-eol) (esc)
  building [=============>                            ]  4/12\r (no-eol) (esc)
  building [=============>                            ]  4/12\r (no-eol) (esc)
  building [=============>                            ]  4/12\r (no-eol) (esc)
  building [================>                         ]  5/12\r (no-eol) (esc)
  building [====================>                     ]  6/12\r (no-eol) (esc)
  building [=======================>                  ]  7/12\r (no-eol) (esc)
  building [===========================>              ]  8/12\r (no-eol) (esc)
  building [===========================>              ]  8/12\r (no-eol) (esc)
  building [==============================>           ]  9/12\r (no-eol) (esc)
  building [==================================>       ] 10/12\r (no-eol) (esc)
  building [=====================================>    ] 11/12\r (no-eol) (esc)
                                                              \r (no-eol) (esc)

tags
  $ cat .hg/localtags
  66f7d451a68b85ed82ff5fcc254daf50c74144bd f
  bebd167eb94d257ace0e814aeb98e6972ed2970d p2
dag
  $ hg debugdag -t -b
  +2:f
  +3:p2
  @temp*f+3
  @default*/p2+2:tip
tip
  $ hg id
  000000000000
glog
  $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n'
  o  11: r11 [] @ 11.00
  |
  o  10: r10 [] @ 10.00
  |
  o    9: r9 [] @ 9.00
  |\
  | o  8: r8 [temp] @ 8.00
  | |
  | o  7: r7 [temp] @ 7.00
  | |
  | o  6: r6 [temp] @ 6.00
  | |
  | o  5: r5 [temp] @ 5.00
  | |
  o |  4: r4 [] @ 4.00
  | |
  o |  3: r3 [] @ 3.00
  | |
  o |  2: r2 [] @ 2.00
  |/
  o  1: r1 [] @ 1.00
  |
  o  0: r0 [] @ 0.00
  

overwritten files, starting on a non-default branch

  $ rm -r .hg
  $ hg init
  $ hg debugbuilddag '@start.@default.:f +3:p2 @temp <f+4 @default /p2 +2' -q -o
tags
  $ cat .hg/localtags
  f778700ebd50fcf282b23a4446bd155da6453eb6 f
  bbccf169769006e2490efd2a02f11c3d38d462bd p2
dag
  $ hg debugdag -t -b
  @start+1
  @default+1:f
  +3:p2
  @temp*f+3
  @default*/p2+2:tip
tip
  $ hg id
  000000000000
glog
  $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n'
  o  11: r11 [] @ 11.00
  |
  o  10: r10 [] @ 10.00
  |
  o    9: r9 [] @ 9.00
  |\
  | o  8: r8 [temp] @ 8.00
  | |
  | o  7: r7 [temp] @ 7.00
  | |
  | o  6: r6 [temp] @ 6.00
  | |
  | o  5: r5 [temp] @ 5.00
  | |
  o |  4: r4 [] @ 4.00
  | |
  o |  3: r3 [] @ 3.00
  | |
  o |  2: r2 [] @ 2.00
  |/
  o  1: r1 [] @ 1.00
  |
  o  0: r0 [start] @ 0.00
  
glog of
  $ hg log -G --template '{rev}: {desc} [{branches}]\n' of
  o  11: r11 []
  |
  o  10: r10 []
  |
  o    9: r9 []
  |\
  | o  8: r8 [temp]
  | |
  | o  7: r7 [temp]
  | |
  | o  6: r6 [temp]
  | |
  | o  5: r5 [temp]
  | |
  o |  4: r4 []
  | |
  o |  3: r3 []
  | |
  o |  2: r2 []
  |/
  o  1: r1 []
  |
  o  0: r0 [start]
  
tags
  $ hg tags -v
  tip                               11:9ffe238a67a2
  p2                                 4:bbccf1697690 local
  f                                  1:f778700ebd50 local
cat of
  $ hg cat of --rev tip
  r11


new and mergeable files

  $ rm -r .hg
  $ hg init
  $ hg debugbuilddag '+2:f +3:p2 @temp <f+4 @default /p2 +2' -q -mn
dag
  $ hg debugdag -t -b
  +2:f
  +3:p2
  @temp*f+3
  @default*/p2+2:tip
tip
  $ hg id
  000000000000
glog
  $ hg log -G --template '{rev}: {desc} [{branches}] @ {date}\n'
  o  11: r11 [] @ 11.00
  |
  o  10: r10 [] @ 10.00
  |
  o    9: r9 [] @ 9.00
  |\
  | o  8: r8 [temp] @ 8.00
  | |
  | o  7: r7 [temp] @ 7.00
  | |
  | o  6: r6 [temp] @ 6.00
  | |
  | o  5: r5 [temp] @ 5.00
  | |
  o |  4: r4 [] @ 4.00
  | |
  o |  3: r3 [] @ 3.00
  | |
  o |  2: r2 [] @ 2.00
  |/
  o  1: r1 [] @ 1.00
  |
  o  0: r0 [] @ 0.00
  
glog mf
  $ hg log -G --template '{rev}: {desc} [{branches}]\n' mf
  o  11: r11 []
  |
  o  10: r10 []
  |
  o    9: r9 []
  |\
  | o  8: r8 [temp]
  | |
  | o  7: r7 [temp]
  | |
  | o  6: r6 [temp]
  | |
  | o  5: r5 [temp]
  | |
  o |  4: r4 []
  | |
  o |  3: r3 []
  | |
  o |  2: r2 []
  |/
  o  1: r1 []
  |
  o  0: r0 []
  

man r4
  $ hg manifest -r4
  mf
  nf0
  nf1
  nf2
  nf3
  nf4
cat r4 mf
  $ hg cat -r4 mf
  0 r0
  1
  2 r1
  3
  4 r2
  5
  6 r3
  7
  8 r4
  9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
man r8
  $ hg manifest -r8
  mf
  nf0
  nf1
  nf5
  nf6
  nf7
  nf8
cat r8 mf
  $ hg cat -r8 mf
  0 r0
  1
  2 r1
  3
  4
  5
  6
  7
  8
  9
  10 r5
  11
  12 r6
  13
  14 r7
  15
  16 r8
  17
  18
  19
  20
  21
  22
  23
man
  $ hg manifest --rev tip
  mf
  nf0
  nf1
  nf10
  nf11
  nf2
  nf3
  nf4
  nf5
  nf6
  nf7
  nf8
  nf9
cat mf
  $ hg cat mf --rev tip
  0 r0
  1
  2 r1
  3
  4 r2
  5
  6 r3
  7
  8 r4
  9
  10 r5
  11
  12 r6
  13
  14 r7
  15
  16 r8
  17
  18 r9
  19
  20 r10
  21
  22 r11
  23