merge: check for path conflicts when updating (issue5628)
When updating to a new revision, check for path conflicts caused by unknown
files in the working directory, and handle these by backing up the file or
directory and replacing it.
Differential Revision: https://phab.mercurial-scm.org/D781
#require symlink
https://bz.mercurial-scm.org/1438
$ hg init
$ ln -s foo link
$ hg add link
$ hg ci -mbad link
$ hg rm link
$ hg ci -mok
$ hg diff -g -r 0:1 > bad.patch
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --no-commit bad.patch
applying bad.patch
$ hg status
R link
? bad.patch