tests/test-empty-file.t

keyword: restore kwtemplater.restrict at the end of wrapped patch.diff

Before this patch, kwdiff doesn't restore kwtemplater.restrict after
invocation of wrapped patch.diff(). This suppresses keyword expansion
at subsequent filelog.read().

Typical usecase of this issue is "hg cat" after "hg diff" with command
server. In this case, kwtemplater.restrict=True is kept in command
server process even after "hg diff".

To ensure kwtemplater.restrict=True while original patch.diff()
running, this patch makes kwdiff() yield values returned by it,
because it returns generator object.

Strictly speaking, if filelog.read() is invoked before completely
evaluating the result of previous patch.diff(), keyword expansion is
still suppressed, because kwtemplater.restrict isn't restored yet.

But this fixing should be reasonable enough, because patch.diff() is
consumed immediately, AFAIK.

  $ 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 ..