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 a
$ cd a
$ echo a > a
$ hg ci -Am0
adding a
$ echo b > b
$ hg ci -Am1
adding b
$ hg tag -r0 default
warning: tag default conflicts with existing branch name
$ hg log
changeset: 2:30a83d1e4a1e
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag default for changeset f7b1eb17ad24
changeset: 1:925d80f479bb
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 1
changeset: 0:f7b1eb17ad24
tag: default
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 0
$ hg update 'tag(default)'
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg parents
changeset: 0:f7b1eb17ad24
tag: default
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 0
$ hg update 'branch(default)'
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg parents
changeset: 2:30a83d1e4a1e
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag default for changeset f7b1eb17ad24
$ cd ..