vfs: copy if EPERM to avoid file stat ambiguity forcibly at closing...
vfs: copy if EPERM to avoid file stat ambiguity forcibly at closing
Now, files (to be truncated) are opened with checkambig=True, only if
localrepository caches it.
Therefore, straightforward "copy if EPERM" is always reasonable to
avoid file stat ambiguity at closing.
This patch makes checkambigatclosing close wrapper copy the target
file, and advance mtime on it after renaming, if EPERM. This can avoid
file stat ambiguity, even if the target file is owned by another (see
issue5418 and issue5584 for detail).
This patch factors main logic out instead of changing
checkambigatclosing._checkambig() directly, in order to reuse it.
