view tests/test-merge5.t @ 31209:dd2364f5180a

localrepo: handle rename with hardlinks properly

In "aftertrans", we rename "journal.*" to "undo.*". We expect "journal.*"
files to disappear after renaming.

However, if "journal.foo" and "undo.foo" refer to a same file (hardlink),
rename may be a no-op, leaving both files on disk, according to Linux
manpage [1]:

    If oldpath and newpath are existing hard links referring to the same
    file, then rename() does nothing, and returns  a  suc‐ cess status.

The POSIX specification [2] is not very clear about what to do.

To be safe, remove "undo.*" before the rename so "journal.*" cannot be left
on disk.

[1]: http://man7.org/linux/man-pages/man2/rename.2.html
[2]: http://pubs.opengroup.org/onlinepubs/9699919799/

  $ hg init
  $ echo This is file a1 > a
  $ echo This is file b1 > b
  $ hg add a b
  $ hg commit -m "commit #0"
  $ echo This is file b22 > b
  $ hg commit -m "comment #1"
  $ hg update 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm b
  $ hg commit -A -m "comment #2"
  removing b
  created new head
  $ hg update 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm b
  $ hg update -c 2
  abort: uncommitted changes
  [255]
  $ hg revert b
  $ hg update -c 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mv a c

Should abort:

  $ hg update 1
  abort: uncommitted changes
  (commit or update --clean to discard changes)
  [255]
  $ mv c a

Should succeed:

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