tests/test-issue1175.t

dirstate: prevent useless util.fspath() invocation for '.'

at first of dirstate.walk() on case insensitive filesystem,
normalization of '.' causes util.fspath() invocation, but '.' is not
cached in it.

this invocation is not only useless, but also harmful: initial "hg
tag" causes creation of ".hgtags" file after dirstate.walk(), and
looking up ".hgtags" in cache will fail, because directory contents of
root is already cached at util.fspath() invocation for '.'.

http://mercurial.selenic.com/bts/issue1175

  $ hg init
  $ touch a
  $ hg ci -Am0
  adding a

  $ hg mv a a1
  $ hg ci -m1

  $ hg co 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg mv a a2
  $ hg up
  note: possible conflict - a was renamed multiple times to:
   a2
   a1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg ci -m2

  $ touch a
  $ hg ci -Am3
  adding a

  $ hg mv a b
  $ hg ci -Am4 a

  $ hg ci --debug --traceback -Am5 b
  b
   b: searching for copy revision for a
   b: copy a:b80de5d138758541c5f05265ad144ab9fa86d1db
  committed changeset 5:89e8e4be0de296fa3d6dd7825ccc44d7dc0f1f3b

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 6 changesets, 4 total revisions

  $ hg export --git tip
  # HG changeset patch
  # User test
  # Date 0 0
  # Node ID 89e8e4be0de296fa3d6dd7825ccc44d7dc0f1f3b
  # Parent  7fc86ba705e717a721dbc361bf8c9bc05a18ca2f
  5
  
  diff --git a/b b/b
  new file mode 100644