tests/test-subrepo-missing.t

matcher: use re2 bindings if available

There are two sets of Python re2 bindings available on the internet;
this code works with both.

Using re2 can greatly improve "hg status" performance when a .hgignore
file becomes even modestly complex.

Example: "hg status" on a clean tree with 134K files, where "hg
debugignore" reports a regexp 4256 bytes in size.

  no .hgignore: 1.76 sec
  Python re:    2.79
  re2:          1.82

The overhead of regexp matching drops from 1.03 seconds with stock
re to 0.06 with re2.

(For comparison, a git repo with the same contents and .gitignore
file runs "git status -s" in 1.71 seconds, i.e. only slightly faster
than hg with re2.)

  $ hg init repo
  $ cd repo
  $ hg init subrepo
  $ echo a > subrepo/a
  $ hg -R subrepo ci -Am adda
  adding a
  $ echo 'subrepo = subrepo' > .hgsub
  $ hg ci -Am addsubrepo
  adding .hgsub
  $ echo b > subrepo/b
  $ hg -R subrepo ci -Am addb
  adding b
  $ hg ci -m updatedsub

ignore blanklines in .hgsubstate

  >>> file('.hgsubstate', 'wb').write('\n\n   \t \n   \n')
  $ hg st --subrepos
  M .hgsubstate
  $ hg revert -qC .hgsubstate

abort more gracefully on .hgsubstate parsing error

  $ cp .hgsubstate .hgsubstate.old
  >>> file('.hgsubstate', 'wb').write('\ninvalid')
  $ hg st --subrepos
  abort: invalid subrepository revision specifier in .hgsubstate line 2
  [255]
  $ mv .hgsubstate.old .hgsubstate

delete .hgsub and revert it

  $ rm .hgsub
  $ hg revert .hgsub
  warning: subrepo spec file .hgsub not found
  warning: subrepo spec file .hgsub not found

delete .hgsubstate and revert it

  $ rm .hgsubstate
  $ hg revert .hgsubstate

delete .hgsub and update

  $ rm .hgsub
  $ hg up 0
  warning: subrepo spec file .hgsub not found
  warning: subrepo spec file .hgsub not found
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg st
  warning: subrepo spec file .hgsub not found
  ! .hgsub
  $ ls subrepo
  a

delete .hgsubstate and update

  $ hg up -C
  warning: subrepo spec file .hgsub not found
  warning: subrepo spec file .hgsub not found
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm .hgsubstate
  $ hg up 0  
  remote changed .hgsubstate which local deleted
  use (c)hanged version or leave (d)eleted? c
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg st
  $ ls subrepo
  a

  $ cd ..