subrepo: add argument to "diff()" to pass "ui" of caller side (issue3712) (API) Color extension achieves colorization by overriding the class of "ui" object just before command execution. Before this patch, "diff()" of abstractsubrepo and classes derived from it has no "ui" argument, so "diff()" of hgsubrepo uses "self._repo.ui" to invoke "cmdutil.diffordiffstat()". For separation of configuration between repositories, revision 573bec4ab7ba changed the initialization source of "self._repo.ui" from "ui"(overridden) to "baseui"(plain) of parent repository. And this caused break of colorization. This patch adds "ui" argument to "diff()" of abstractsubrepo and classes derived from it to pass "ui" object of caller side.

  $ "$TESTDIR/hghave" execbit || exit 80

  $ hg init
  $ echo a > a
  $ hg ci -Am'not executable'
  adding a

  $ chmod +x a
  $ hg ci -m'executable'
  $ hg id
  79abf14474dc tip

Make sure we notice the change of mode if the cached size == -1:

  $ hg rm a
  $ hg revert -r 0 a
  $ hg debugstate
  n   0         -1 unset               a
  $ hg status
  M a

  $ hg up 0
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id
  d69afc33ff8a
  $ test -x a && echo executable -- bad || echo not executable -- good
  not executable -- good