view tests/test-histedit-fold-non-commute.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.

  $ . "$TESTDIR/histedit-helpers.sh"

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > histedit=
  > EOF

  $ modwithdate ()
  > {
  >     echo $1 > $1
  >     hg ci -m $1 -d "$2 0"
  > }

  $ initrepo ()
  > {
  >     hg init $1
  >     cd $1
  >     for x in a b c d e f ; do
  >         echo $x$x$x$x$x > $x
  >         hg add $x
  >     done
  >     hg ci -m 'Initial commit'
  >     modwithdate a 1
  >     modwithdate b 2
  >     modwithdate c 3
  >     modwithdate d 4
  >     modwithdate e 5
  >     modwithdate f 6
  >     echo 'I can haz no commute' > e
  >     hg ci -m 'does not commute with e' -d '7 0'
  >     cd ..
  > }

  $ initrepo r
  $ cd r
Initial generation of the command files

  $ EDITED="$TESTTMP/editedhistory"
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 3 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 4 >> $EDITED
  $ hg log --template 'fold {node|short} {rev} {desc}\n' -r 7 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 5 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 6 >> $EDITED
  $ cat $EDITED
  pick 092e4ce14829 3 c
  pick ae78f4c9d74f 4 d
  fold 42abbb61bede 7 does not commute with e
  pick 7f3755409b00 5 e
  pick dd184f2faeb0 6 f

log before edit
  $ hg log --graph
  @  changeset:   7:42abbb61bede
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:07 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   6:dd184f2faeb0
  |  user:        test
  |  date:        Thu Jan 01 00:00:06 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:7f3755409b00
  |  user:        test
  |  date:        Thu Jan 01 00:00:05 1970 +0000
  |  summary:     e
  |
  o  changeset:   4:ae78f4c9d74f
  |  user:        test
  |  date:        Thu Jan 01 00:00:04 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:092e4ce14829
  |  user:        test
  |  date:        Thu Jan 01 00:00:03 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:40ccdd8beb95
  |  user:        test
  |  date:        Thu Jan 01 00:00:02 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:cd997a145b29
  |  user:        test
  |  date:        Thu Jan 01 00:00:01 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

edit the history
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (fold 42abbb61bede)
  (hg histedit --continue to resume)

fix up
  $ echo 'I can haz no commute' > e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ HGEDITOR=cat hg histedit --continue 2>&1 | fixbundle | grep -v '2 files removed'
  d
  ***
  does not commute with e
  
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: changed d
  HG: changed e
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 7f3755409b00)
  (hg histedit --continue to resume)

just continue this time
keep the non-commuting change, and thus the pending change will be dropped
  $ hg revert -r 'p1()' e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg diff
  $ hg histedit --continue 2>&1 | fixbundle
  7f3755409b00: skipping changeset (no changes)

log after edit
  $ hg log --graph
  @  changeset:   5:1300355b1a54
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:06 1970 +0000
  |  summary:     f
  |
  o  changeset:   4:e2ac33269083
  |  user:        test
  |  date:        Thu Jan 01 00:00:07 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:092e4ce14829
  |  user:        test
  |  date:        Thu Jan 01 00:00:03 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:40ccdd8beb95
  |  user:        test
  |  date:        Thu Jan 01 00:00:02 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:cd997a145b29
  |  user:        test
  |  date:        Thu Jan 01 00:00:01 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

contents of e
  $ hg cat e
  I can haz no commute

manifest
  $ hg manifest
  a
  b
  c
  d
  e
  f

  $ cd ..

Repeat test using "roll", not "fold". "roll" folds in changes but drops message and date

  $ initrepo r2
  $ cd r2

Initial generation of the command files

  $ EDITED="$TESTTMP/editedhistory.2"
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 3 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 4 >> $EDITED
  $ hg log --template 'roll {node|short} {rev} {desc}\n' -r 7 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 5 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 6 >> $EDITED
  $ cat $EDITED
  pick 092e4ce14829 3 c
  pick ae78f4c9d74f 4 d
  roll 42abbb61bede 7 does not commute with e
  pick 7f3755409b00 5 e
  pick dd184f2faeb0 6 f

log before edit
  $ hg log --graph
  @  changeset:   7:42abbb61bede
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:07 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   6:dd184f2faeb0
  |  user:        test
  |  date:        Thu Jan 01 00:00:06 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:7f3755409b00
  |  user:        test
  |  date:        Thu Jan 01 00:00:05 1970 +0000
  |  summary:     e
  |
  o  changeset:   4:ae78f4c9d74f
  |  user:        test
  |  date:        Thu Jan 01 00:00:04 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:092e4ce14829
  |  user:        test
  |  date:        Thu Jan 01 00:00:03 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:40ccdd8beb95
  |  user:        test
  |  date:        Thu Jan 01 00:00:02 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:cd997a145b29
  |  user:        test
  |  date:        Thu Jan 01 00:00:01 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

edit the history
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (roll 42abbb61bede)
  (hg histedit --continue to resume)

fix up
  $ echo 'I can haz no commute' > e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle | grep -v '2 files removed'
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 7f3755409b00)
  (hg histedit --continue to resume)

just continue this time
  $ hg revert -r 'p1()' e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  7f3755409b00: skipping changeset (no changes)

log after edit
  $ hg log --graph
  @  changeset:   5:b538bcb461be
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:06 1970 +0000
  |  summary:     f
  |
  o  changeset:   4:317e37cb6d66
  |  user:        test
  |  date:        Thu Jan 01 00:00:04 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:092e4ce14829
  |  user:        test
  |  date:        Thu Jan 01 00:00:03 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:40ccdd8beb95
  |  user:        test
  |  date:        Thu Jan 01 00:00:02 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:cd997a145b29
  |  user:        test
  |  date:        Thu Jan 01 00:00:01 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

contents of e
  $ hg cat e
  I can haz no commute

manifest
  $ hg manifest
  a
  b
  c
  d
  e
  f

description is taken from rollup target commit

  $ hg log --debug --rev 4
  changeset:   4:317e37cb6d66c1c84628c00e5bf4c8c292831951
  phase:       draft
  parent:      3:092e4ce14829f4974399ce4316d59f64ef0b6725
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    4:b068a323d969f22af1296ec6a5ea9384cef437ac
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  files:       d e
  extra:       branch=default
  extra:       histedit_source=ae78f4c9d74ffa4b6cb5045001c303fe9204e890,42abbb61bede6f4366fa1e74a664343e5d558a70
  description:
  d
  
  

done with repo r2

  $ cd ..