tests/test-revset-dirstate-parents.t

configitems: add a basic class to hold config item information

The goal of this class is allow explicit declaration for the available config
option. This class will hold the data for one specific config item.

To keep it simple we start centralizing the handling of the default config value.

In the future we can expect more data to be carried on this class. For example:
 - documentation,
 - status (experimental, advanced, normal, deprecated),
 - aliases,
 - expected type,
 - etc...

  $ HGENCODING=utf-8
  $ export HGENCODING

  $ try() {
  >   hg debugrevspec --debug $@
  > }

  $ log() {
  >   hg log --template '{rev}\n' -r "$1"
  > }

  $ hg init repo
  $ cd repo

  $ try 'p1()'
  (func
    ('symbol', 'p1')
    None)
  * set:
  <baseset []>
  $ try 'p2()'
  (func
    ('symbol', 'p2')
    None)
  * set:
  <baseset []>
  $ try 'parents()'
  (func
    ('symbol', 'parents')
    None)
  * set:
  <baseset+ []>

null revision
  $ log 'p1()'
  $ log 'p2()'
  $ log 'parents()'

working dir with a single parent
  $ echo a > a
  $ hg ci -Aqm0
  $ log 'p1()'
  0
  $ log 'tag() and p1()'
  $ log 'p2()'
  $ log 'parents()'
  0
  $ log 'tag() and parents()'

merge in progress
  $ echo b > b
  $ hg ci -Aqm1
  $ hg up -q 0
  $ echo c > c
  $ hg ci -Aqm2
  $ hg merge -q
  $ log 'p1()'
  2
  $ log 'p2()'
  1
  $ log 'tag() and p2()'
  $ log 'parents()'
  1
  2

  $ cd ..