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.