tests/test-confused-revert.t

scmutil: consistently return subrepos relative to ctx1 from itersubrepos()

Previously, if a subrepo was added in ctx2 and then compared to another without
it (ctx1), the subrepo for ctx2 was returned amongst all of the ctx1 based
subrepos, since no subrepo exists in ctx1 to replace it in the 'subpaths' dict.
The two callers of this, basectx.status() and cmdutil.diffordiffstat(), both
compare the yielded subrepo against ctx2, and thus saw no changes when ctx2's
subrepo was returned.  The tests here previously didn't mention 's/a' for the
'p1()' case.

This appears to have been a known issue, because some diffordiffstat() comments
mention that the subpath disappeared, and "the best we can do is ignore it".  I
originally ran into the issue with some custom convert code to flatten a tree of
subrepos causing hg.putcommit() to abort, but this new behavior seems like the
correct status and diff behavior regardless.  (The abort in convert isn't
something users will see, because convert doesn't currently support subrepos in
the official repo.)

  $ hg init
  $ echo foo > a
  $ hg add a
  $ hg commit -m "1"

  $ echo bar > b
  $ hg add b
  $ hg remove a

Should show a removed and b added:

  $ hg status
  A b
  R a

  $ hg revert --all
  undeleting a
  forgetting b

Should show b unknown and a back to normal:

  $ hg status
  ? b

  $ rm b

  $ hg co -C 0
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo foo-a > a
  $ hg commit -m "2a"

  $ hg co -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo foo-b > a
  $ hg commit -m "2b"
  created new head

  $ HGMERGE=true hg merge 1
  merging a
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Should show foo-b:

  $ cat a
  foo-b

  $ echo bar > b
  $ hg add b
  $ rm a
  $ hg remove a

Should show a removed and b added:

  $ hg status
  A b
  R a

Revert should fail:

  $ hg revert
  abort: uncommitted merge with no revision specified
  (use "hg update" or see "hg help revert")
  [255]

Revert should be ok now:

  $ hg revert -r2 --all
  undeleting a
  forgetting b

Should show b unknown and a marked modified (merged):

  $ hg status
  M a
  ? b

Should show foo-b:

  $ cat a
  foo-b