tests/test-issue522.t

revset: explicitely tag alias arguments for expansion

The current revset alias expansion code works like:
1- Get the replacement tree
2- Substitute the variables in the replacement tree
3- Expand the replacement tree

It makes it easy to substitute alias arguments because the placeholders
are always replaced before the updated replacement tree is expanded
again. Unfortunately, to fix other alias expansion issues, we need to
reorder the sequence and delay the argument substitution. To solve this,
a new "virtual" construct called _aliasarg() is introduced and injected
when parsing the aliases definitions. Only _aliasarg() will be
substituted in the argument expansion phase instead of all regular
matching string. We also check user inputs do not contain unexpected
_aliasarg() instances to avoid argument injections.

http://mercurial.selenic.com/bts/issue522

In the merge below, the file "foo" has the same contents in both
parents, but if we look at the file-level history, we'll notice that
the version in p1 is an ancestor of the version in p2. This test makes
sure that we'll use the version from p2 in the manifest of the merge
revision.

  $ hg init

  $ echo foo > foo
  $ hg ci -qAm 'add foo'

  $ echo bar >> foo
  $ hg ci -m 'change foo'

  $ hg backout -r tip -m 'backout changed foo'
  reverting foo
  changeset 2:4d9e78aaceee backs out changeset 1:b515023e500e

  $ hg up -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ touch bar
  $ hg ci -qAm 'add bar'

  $ hg merge --debug
    searching for copies back to rev 1
    unmatched files in local:
     bar
  resolving manifests
   overwrite: False, partial: False
   ancestor: bbd179dfa0a7, local: 71766447bdbb+, remote: 4d9e78aaceee
   foo: remote is newer -> g
  updating: foo 1/1 files (100.00%)
  getting foo
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg debugstate | grep foo
  n   0         -2 unset               foo

  $ hg st -A foo
  M foo

  $ hg ci -m 'merge'

  $ hg manifest --debug | grep foo
  c6fc755d7e68f49f880599da29f15add41f42f5a 644   foo

  $ hg debugindex foo
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0       5      0       0 2ed2a3912a0b 000000000000 000000000000
       1         5       9      1       1 6f4310b00b9a 2ed2a3912a0b 000000000000
       2        14       5      2       2 c6fc755d7e68 6f4310b00b9a 000000000000