tests/test-empty-file.t

context: don't complain about a matcher's subrepo paths in changectx.walk()

Previously, the first added test printed the following:

  $ hg files -S -r '.^' sub1/sub2/folder
  sub1/sub2/folder: no such file in rev 9bb10eebee29
  sub1/sub2/folder: no such file in rev 9bb10eebee29
  sub1/sub2/folder/test.txt

One warning occured each time a subrepo was crossed into.

The second test ensures that the matcher copy stays in place.  Without the copy,
the bad() function becomes an increasingly longer chain, and no message would be
printed out for a file missing in the subrepo because the predicate would match
in one of the replaced methods.  Manifest doesn't know anything about subrepos,
so it needs help ignoring subrepos when complaining about bad files.

  $ hg init a
  $ cd a
  $ touch empty1
  $ hg add empty1
  $ hg commit -m 'add empty1'

  $ touch empty2
  $ hg add empty2
  $ hg commit -m 'add empty2'

  $ hg up -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ touch empty3
  $ hg add empty3
  $ hg commit -m 'add empty3'
  created new head

  $ hg heads
  changeset:   2:a1cb177e0d44
  tag:         tip
  parent:      0:1e1d9c4e5b64
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     add empty3
  
  changeset:   1:097d2b0e17f6
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     add empty2
  

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

Before changeset 05257fd28591, we didn't notice the
empty file that came from rev 1:

  $ hg status
  M empty2
  $ hg commit -m merge
  $ hg manifest --debug tip
  b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty1
  b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty2
  b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty3

  $ cd ..