Traditionally, unpack_trees_options->reset was used to signal that it
was okay to delete any untracked files in the way. This was used by
`git read-tree --reset`, but then started appearing in other places as
well. However, many of the other uses should not be deleting untracked
files in the way. Change this value to an enum so that a value of 1
(i.e. "true") can be split into two:
UNPACK_RESET_PROTECT_UNTRACKED,
UNPACK_RESET_OVERWRITE_UNTRACKED
In order to catch accidental misuses (i.e. where folks call it the way
they traditionally used to), define the special enum value of
UNPACK_RESET_INVALID = 1
which will trigger a BUG().
Modify existing callers so that
read-tree --reset
reset --hard
checkout --force
continue using the UNPACK_RESET_OVERWRITE_UNTRACKED logic, while other
callers, including
am
checkout without --force
stash (though currently dead code; reset always had a value of 0)
numerous callers from rebase/sequencer to reset_head()
will use the new UNPACK_RESET_PROTECT_UNTRACKED value.
Also, note that it has been reported that 'git checkout <treeish>
<pathspec>' currently also allows overwriting untracked files[1]. That
case should also be fixed, but it does not use unpack_trees() and thus
is outside the scope of the current changes.
[1] https://lore.kernel.org/git/15dad590-087e-5a48-9238-5d2826950506@gmail.com/
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Noting that unpack_trees treats reset=1 & update=1 as license to nuke
untracked files, I looked for code paths that use this combination and
tried to generate testcases which demonstrated unintentional loss of
untracked files and directories. I found several.
I also include testcases for `git reset --{hard,merge,keep}`. A hard
reset is perhaps the most direct test of unpack_tree's reset=1 behavior,
but we cannot make `git reset --hard` preserve untracked files without
some migration work.
Also, the two commands `checkout --force` (because of the --force) and
`read-tree --reset` (because it's plumbing and we need to keep it
backward compatible) were left out as we expect those to continue
removing untracked files and directories.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
