git/reset.c
Elijah Newren 480d3d6bf9 Change unpack_trees' 'reset' flag into an enum
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>
2021-09-27 13:38:37 -07:00

143 lines
4.1 KiB
C

#include "git-compat-util.h"
#include "cache-tree.h"
#include "lockfile.h"
#include "refs.h"
#include "reset.h"
#include "run-command.h"
#include "tree-walk.h"
#include "tree.h"
#include "unpack-trees.h"
int reset_head(struct repository *r, struct object_id *oid, const char *action,
const char *switch_to_branch, unsigned flags,
const char *reflog_orig_head, const char *reflog_head,
const char *default_reflog_action)
{
unsigned detach_head = flags & RESET_HEAD_DETACH;
unsigned reset_hard = flags & RESET_HEAD_HARD;
unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
unsigned update_orig_head = flags & RESET_ORIG_HEAD;
struct object_id head_oid;
struct tree_desc desc[2] = { { NULL }, { NULL } };
struct lock_file lock = LOCK_INIT;
struct unpack_trees_options unpack_tree_opts = { 0 };
struct tree *tree;
const char *reflog_action;
struct strbuf msg = STRBUF_INIT;
size_t prefix_len;
struct object_id *orig = NULL, oid_orig,
*old_orig = NULL, oid_old_orig;
int ret = 0, nr = 0;
if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
BUG("Not a fully qualified branch: '%s'", switch_to_branch);
if (!refs_only && repo_hold_locked_index(r, &lock, LOCK_REPORT_ON_ERROR) < 0) {
ret = -1;
goto leave_reset_head;
}
if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
ret = error(_("could not determine HEAD revision"));
goto leave_reset_head;
}
if (!oid)
oid = &head_oid;
if (refs_only)
goto reset_head_refs;
setup_unpack_trees_porcelain(&unpack_tree_opts, action);
unpack_tree_opts.head_idx = 1;
unpack_tree_opts.src_index = r->index;
unpack_tree_opts.dst_index = r->index;
unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
unpack_tree_opts.update = 1;
unpack_tree_opts.merge = 1;
unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
init_checkout_metadata(&unpack_tree_opts.meta, switch_to_branch, oid, NULL);
if (!detach_head)
unpack_tree_opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;
if (repo_read_index_unmerged(r) < 0) {
ret = error(_("could not read index"));
goto leave_reset_head;
}
if (!reset_hard && !fill_tree_descriptor(r, &desc[nr++], &head_oid)) {
ret = error(_("failed to find tree of %s"),
oid_to_hex(&head_oid));
goto leave_reset_head;
}
if (!fill_tree_descriptor(r, &desc[nr++], oid)) {
ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
goto leave_reset_head;
}
if (unpack_trees(nr, desc, &unpack_tree_opts)) {
ret = -1;
goto leave_reset_head;
}
tree = parse_tree_indirect(oid);
prime_cache_tree(r, r->index, tree);
if (write_locked_index(r->index, &lock, COMMIT_LOCK) < 0) {
ret = error(_("could not write index"));
goto leave_reset_head;
}
reset_head_refs:
reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : default_reflog_action);
prefix_len = msg.len;
if (update_orig_head) {
if (!get_oid("ORIG_HEAD", &oid_old_orig))
old_orig = &oid_old_orig;
if (!get_oid("HEAD", &oid_orig)) {
orig = &oid_orig;
if (!reflog_orig_head) {
strbuf_addstr(&msg, "updating ORIG_HEAD");
reflog_orig_head = msg.buf;
}
update_ref(reflog_orig_head, "ORIG_HEAD", orig,
old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
} else if (old_orig)
delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
}
if (!reflog_head) {
strbuf_setlen(&msg, prefix_len);
strbuf_addstr(&msg, "updating HEAD");
reflog_head = msg.buf;
}
if (!switch_to_branch)
ret = update_ref(reflog_head, "HEAD", oid, orig,
detach_head ? REF_NO_DEREF : 0,
UPDATE_REFS_MSG_ON_ERR);
else {
ret = update_ref(reflog_head, switch_to_branch, oid,
NULL, 0, UPDATE_REFS_MSG_ON_ERR);
if (!ret)
ret = create_symref("HEAD", switch_to_branch,
reflog_head);
}
if (run_hook)
run_hook_le(NULL, "post-checkout",
oid_to_hex(orig ? orig : null_oid()),
oid_to_hex(oid), "1", NULL);
leave_reset_head:
strbuf_release(&msg);
rollback_lock_file(&lock);
clear_unpack_trees_porcelain(&unpack_tree_opts);
while (nr)
free((void *)desc[--nr].buffer);
return ret;
}