tests/test-merge4.t

dirstate.walk: don't report same file stat multiple times

dirstate.walk() generates pairs of filename and a stat-like
object. After "hg mv foo Foo", it generates one pair for "foo" and one
for "Foo", as it should. However, on case-insensitive file systems,
when it tries to stat to get the disk state as well, it gets the same
stat result for both names. This confuses at least
scmutil._interestingfiles(), making it think that "foo" was forgotten
rather than removed. That, in turn, makes "hg addremove" add "foo"
back, resulting in both cases in the dirstate, as reported in
issue4590.

This change only takes care of the "if unknown" branch. A similar fix
should perhaps be applied to the other branch.

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg update 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #2"
  created new head
  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ rm b
  $ echo This is file c22 > c

Test hg behaves when committing with a missing file added by a merge

  $ hg commit -m "commit #3"
  abort: cannot commit merge with missing files
  [255]