view tests/test-convert-cvs-branch.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.

#require cvs

This is https://bz.mercurial-scm.org/1148
and https://bz.mercurial-scm.org/1447

  $ cvscall()
  > {
  >     cvs -f "$@" > /dev/null
  > }
  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > convert =
  > [convert]
  > cvsps.cache = 0
  > EOF

create cvs repository

  $ mkdir cvsrepo
  $ cd cvsrepo
  $ CVSROOT=`pwd`
  $ export CVSROOT
  $ CVS_OPTIONS=-f
  $ export CVS_OPTIONS
  $ cd ..
  $ rmdir cvsrepo
  $ cvscall -q -d "$CVSROOT" init

Create a new project

  $ mkdir src
  $ cd src
  $ echo "1" > a
  $ echo "1" > b
  $ cvscall import -m "init" src v0 r0 | sort
  $ cd ..
  $ cvscall co src
  cvs checkout: Updating src
  $ cd src

Branch the project

  $ cvscall tag -b BRANCH
  cvs tag: Tagging .
  $ cvscall up -r BRANCH > /dev/null
  cvs update: Updating .

Modify file a, then b, then a

  $ sleep 1
  $ echo "2" > a
  $ cvscall ci -m "mod a"
  cvs commit: Examining .
  $ echo "2" > b
  $ cvscall ci -m "mod b"
  cvs commit: Examining .
  $ sleep 1
  $ echo "3" > a
  $ cvscall ci -m "mod a again"
  cvs commit: Examining .

Convert

  $ cd ..
  $ hg convert src
  assuming destination src-hg
  initializing destination src-hg repository
  connecting to $TESTTMP/cvsrepo
  scanning source...
  collecting CVS rlog
  7 log entries
  creating changesets
  5 changeset entries
  sorting...
  converting...
  4 Initial revision
  3 init
  2 mod a
  1 mod b
  0 mod a again
  updating tags

Check the result

  $ hg -R src-hg log -G --template '{rev} ({branches}) {desc} files: {files}\n'
  o  5 () update tags files: .hgtags
  |
  | o  4 (BRANCH) mod a again files: a
  | |
  | o  3 (BRANCH) mod b files: b
  | |
  | o  2 (BRANCH) mod a files: a
  | |
  | o  1 (v0) init files:
  |/
  o  0 () Initial revision files: a b
  


issue 1447

  $ cvscall()
  > {
  >     cvs -f "$@" > /dev/null
  >     sleep 1
  > }
  $ cvsci()
  > {
  >     cvs -f ci "$@" >/dev/null
  >     sleep 1
  > }
  $ cvscall -Q -d `pwd`/cvsmaster2 init
  $ cd cvsmaster2
  $ CVSROOT=`pwd`
  $ export CVSROOT
  $ mkdir foo
  $ cd ..
  $ cvscall -Q co -d cvswork2 foo
  $ cd cvswork2
  $ echo foo > a.txt
  $ echo bar > b.txt
  $ cvscall -Q add a.txt b.txt
  $ cvsci -m "Initial commit"
  cvs commit: Examining .
  $ echo foo > b.txt
  $ cvsci -m "Fix b on HEAD"
  cvs commit: Examining .
  $ echo bar > a.txt
  $ cvsci -m "Small fix in a on HEAD"
  cvs commit: Examining .
  $ cvscall -Q tag -b BRANCH
  $ cvscall -Q up -P -rBRANCH
  $ echo baz > b.txt
  $ cvsci -m "Change on BRANCH in b"
  cvs commit: Examining .
  $ hg debugcvsps -x --parents foo
  collecting CVS rlog
  5 log entries
  creating changesets
  4 changeset entries
  ---------------------
  PatchSet 1 
  Date: * (glob)
  Author: * (glob)
  Branch: HEAD
  Tag: (none) 
  Log:
  Initial commit
  
  Members: 
  	a.txt:INITIAL->1.1 
  	b.txt:INITIAL->1.1 
  
  ---------------------
  PatchSet 2 
  Date: * (glob)
  Author: * (glob)
  Branch: HEAD
  Tag: (none) 
  Branchpoints: BRANCH 
  Parent: 1
  Log:
  Fix b on HEAD
  
  Members: 
  	b.txt:1.1->1.2 
  
  ---------------------
  PatchSet 3 
  Date: * (glob)
  Author: * (glob)
  Branch: HEAD
  Tag: (none) 
  Branchpoints: BRANCH 
  Parent: 2
  Log:
  Small fix in a on HEAD
  
  Members: 
  	a.txt:1.1->1.2 
  
  ---------------------
  PatchSet 4 
  Date: * (glob)
  Author: * (glob)
  Branch: BRANCH
  Tag: (none) 
  Parent: 3
  Log:
  Change on BRANCH in b
  
  Members: 
  	b.txt:1.2->1.2.2.1 
  

  $ cd ..