tests/test-merge-subrepos.t

convert: when converting from Perforce use original local encoding by default

On Windows Perforce command line client uses default system locale to encode
output. Using 'latin_1' causes locale-specific characters to be replaced with
question marks. With this patch we will use default locale by default whilst
allowing to specify it explicity with 'convert.p4.encoding' config option.

This is a potentially breaking change for any scripts relying on output treated
as in 'latin_1' encoding.

Also because hgext.convert.convcmd overwrites detected default system locale
with UTF-8 we had to introduce an import cycle in hgext.convert.p4 to retrieve
originally detected encoding from hgext.convert.convcmd.

  $ hg init

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

  $ hg init subrepo
  $ echo 'subrepo = http://example.net/libfoo' > .hgsub
  $ hg ci -qAm 'added subrepo'

  $ hg up -qC 0
  $ echo ax > a
  $ hg ci -m 'changed a'
  created new head

  $ hg up -qC 1
  $ cd subrepo
  $ echo b > b
  $ hg add b
  $ cd ..

Should fail, since there are added files to subrepo:

  $ hg merge
  abort: uncommitted changes in subrepository 'subrepo'
  [255]