templatekw: compare target context and its parent exactly (issue4690) Before this patch, template keywords `{file_mods}`, `{file_adds}` and `{file_dels}` use values gotten by `repo.status(ctx.p1().node(), ctx.node())`. But this doesn't work as expected if `ctx` is `memctx` or `workingcommitctx`. Typical case of templating with these contexts is customization of the text shown in the commit message editor by `[committemplate]` configuration. In this case, `ctx.node()` returns None and it causes comparison between `ctx.p1()` and `workingctx`. `workingctx` lists up all changed files in the working directory even at selective committing. BTW, `{files}` uses `ctx.files()` and it works as expected. To compare target context and its parent exactly, this patch passes `ctx.p1()` and `ctx` without `node()`-nize. This avoids unexpected comparison with `workingctx`. This patch uses a little redundant template configurations in `test-commit.t`, but they are needed to avoid regression around problems fixed by a4958cdb2202 and 1e6fb8db666e: accessing on `ctx` may break `ctx._status` field.

  $ 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]