tests/test-mq-qrefresh-replace-log-message.t

config: discard "%unset" values defined in the other files read in previously

Before this patch, "%unset" can't unset values defined in the other
files read in previously, even though online help document says that
it can. It can unset only values defined in the same configuration
file.

For example, the value defined in "~/.hgrc" can't be unset by "%unset"
in ".hg/hgrc" of the repository.

This patch records "%unset"-ed values in "config.parse()", and
discards corresponding values in "config.update()".

Environment setup for MQ

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ hg init
  $ hg qinit

Should fail if no patches applied

  $ hg qrefresh
  no patches applied
  [1]
  $ hg qrefresh -e
  no patches applied
  [1]
  $ hg qnew -m "First commit message" first-patch
  $ echo aaaa > file
  $ hg add file
  $ hg qrefresh

Should display 'First commit message'

  $ hg log -l1 --template "{desc}\n"
  First commit message

Testing changing message with -m

  $ echo bbbb > file
  $ hg qrefresh -m "Second commit message"

Should display 'Second commit message'

  $ hg log -l1 --template "{desc}\n"
  Second commit message

Testing changing message with -l

  $ echo "Third commit message" > logfile
  $ echo " This is the 3rd log message" >> logfile
  $ echo bbbb > file
  $ hg qrefresh -l logfile

Should display 'Third commit message\\\n This is the 3rd log message'

  $ hg log -l1 --template "{desc}\n"
  Third commit message
   This is the 3rd log message

Testing changing message with -l-

  $ hg qnew -m "First commit message" second-patch
  $ echo aaaa > file2
  $ hg add file2
  $ echo bbbb > file2
  $ (echo "Fifth commit message"; echo " This is the 5th log message") | hg qrefresh -l-

Should display 'Fifth commit message\\\n This is the 5th log message'

  $ hg log -l1 --template "{desc}\n"
  Fifth commit message
   This is the 5th log message