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![Conrad Irwin](/assets/img/avatar_default.png)
"git branch -M <foo> <current-branch>" allows updating the current branch which HEAD points, without the necessary house-keeping that git reset normally does to make this operation sensible. It also leaves the reflog in a confusing state (you would be warned when trying to read it). "git checkout -B <current branch> <foo>" is also partly vulnerable to this bug; due to inconsistent pre-flight checks it would perform half of its task and then abort just before rewriting the branch. Again this manifested itself as the index file getting out-of-sync with HEAD. "git branch -f" already guarded against this problem, and aborts with a fatal error. Update "git branch -M", "git checkout -B" and "git branch -f" to share the same check before allowing a branch to be created. These prevent you from updating the current branch. We considered suggesting the use of "git reset" in the failure message but concluded that it was not possible to discern what the user was actually trying to do. Signed-off-by: Conrad Irwin <conrad.irwin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
246 lines
5.8 KiB
C
246 lines
5.8 KiB
C
#include "cache.h"
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#include "branch.h"
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#include "refs.h"
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#include "remote.h"
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#include "commit.h"
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struct tracking {
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struct refspec spec;
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char *src;
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const char *remote;
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int matches;
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};
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static int find_tracked_branch(struct remote *remote, void *priv)
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{
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struct tracking *tracking = priv;
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if (!remote_find_tracking(remote, &tracking->spec)) {
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if (++tracking->matches == 1) {
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tracking->src = tracking->spec.src;
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tracking->remote = remote->name;
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} else {
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free(tracking->spec.src);
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if (tracking->src) {
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free(tracking->src);
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tracking->src = NULL;
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}
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}
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tracking->spec.src = NULL;
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}
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return 0;
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}
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static int should_setup_rebase(const char *origin)
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{
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switch (autorebase) {
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case AUTOREBASE_NEVER:
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return 0;
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case AUTOREBASE_LOCAL:
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return origin == NULL;
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case AUTOREBASE_REMOTE:
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return origin != NULL;
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case AUTOREBASE_ALWAYS:
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return 1;
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}
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return 0;
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}
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void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
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{
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const char *shortname = remote + 11;
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int remote_is_branch = !prefixcmp(remote, "refs/heads/");
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struct strbuf key = STRBUF_INIT;
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int rebasing = should_setup_rebase(origin);
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if (remote_is_branch
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&& !strcmp(local, shortname)
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&& !origin) {
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warning("Not setting branch %s as its own upstream.",
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local);
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return;
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}
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strbuf_addf(&key, "branch.%s.remote", local);
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git_config_set(key.buf, origin ? origin : ".");
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strbuf_reset(&key);
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strbuf_addf(&key, "branch.%s.merge", local);
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git_config_set(key.buf, remote);
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if (rebasing) {
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strbuf_reset(&key);
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strbuf_addf(&key, "branch.%s.rebase", local);
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git_config_set(key.buf, "true");
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}
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if (flag & BRANCH_CONFIG_VERBOSE) {
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strbuf_reset(&key);
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strbuf_addstr(&key, origin ? "remote" : "local");
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/* Are we tracking a proper "branch"? */
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if (remote_is_branch) {
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strbuf_addf(&key, " branch %s", shortname);
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if (origin)
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strbuf_addf(&key, " from %s", origin);
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}
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else
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strbuf_addf(&key, " ref %s", remote);
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printf("Branch %s set up to track %s%s.\n",
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local, key.buf,
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rebasing ? " by rebasing" : "");
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}
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strbuf_release(&key);
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}
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/*
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* This is called when new_ref is branched off of orig_ref, and tries
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* to infer the settings for branch.<new_ref>.{remote,merge} from the
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* config.
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*/
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static int setup_tracking(const char *new_ref, const char *orig_ref,
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enum branch_track track)
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{
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struct tracking tracking;
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if (strlen(new_ref) > 1024 - 7 - 7 - 1)
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return error("Tracking not set up: name too long: %s",
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new_ref);
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memset(&tracking, 0, sizeof(tracking));
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tracking.spec.dst = (char *)orig_ref;
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if (for_each_remote(find_tracked_branch, &tracking))
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return 1;
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if (!tracking.matches)
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switch (track) {
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case BRANCH_TRACK_ALWAYS:
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case BRANCH_TRACK_EXPLICIT:
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case BRANCH_TRACK_OVERRIDE:
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break;
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default:
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return 1;
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}
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if (tracking.matches > 1)
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return error("Not tracking: ambiguous information for ref %s",
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orig_ref);
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install_branch_config(BRANCH_CONFIG_VERBOSE, new_ref, tracking.remote,
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tracking.src ? tracking.src : orig_ref);
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free(tracking.src);
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return 0;
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}
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int validate_new_branchname(const char *name, struct strbuf *ref, int force)
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{
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const char *head;
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unsigned char sha1[20];
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if (strbuf_check_branch_ref(ref, name))
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die("'%s' is not a valid branch name.", name);
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if (!ref_exists(ref->buf))
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return 0;
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else if (!force)
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die("A branch named '%s' already exists.", name);
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head = resolve_ref("HEAD", sha1, 0, NULL);
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if (!is_bare_repository() && head && !strcmp(head, ref->buf))
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die("Cannot force update the current branch.");
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return 1;
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}
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void create_branch(const char *head,
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const char *name, const char *start_name,
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int force, int reflog, enum branch_track track)
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{
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struct ref_lock *lock = NULL;
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struct commit *commit;
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unsigned char sha1[20];
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char *real_ref, msg[PATH_MAX + 20];
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struct strbuf ref = STRBUF_INIT;
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int forcing = 0;
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int dont_change_ref = 0;
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int explicit_tracking = 0;
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if (track == BRANCH_TRACK_EXPLICIT || track == BRANCH_TRACK_OVERRIDE)
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explicit_tracking = 1;
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if (validate_new_branchname(name, &ref, force || track == BRANCH_TRACK_OVERRIDE)) {
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if (!force)
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dont_change_ref = 1;
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else
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forcing = 1;
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}
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real_ref = NULL;
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if (get_sha1(start_name, sha1))
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die("Not a valid object name: '%s'.", start_name);
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switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
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case 0:
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/* Not branching from any existing branch */
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if (explicit_tracking)
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die("Cannot setup tracking information; starting point is not a branch.");
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break;
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case 1:
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/* Unique completion -- good, only if it is a real branch */
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if (prefixcmp(real_ref, "refs/heads/") &&
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prefixcmp(real_ref, "refs/remotes/")) {
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if (explicit_tracking)
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die("Cannot setup tracking information; starting point is not a branch.");
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else
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real_ref = NULL;
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}
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break;
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default:
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die("Ambiguous object name: '%s'.", start_name);
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break;
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}
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if ((commit = lookup_commit_reference(sha1)) == NULL)
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die("Not a valid branch point: '%s'.", start_name);
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hashcpy(sha1, commit->object.sha1);
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if (!dont_change_ref) {
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lock = lock_any_ref_for_update(ref.buf, NULL, 0);
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if (!lock)
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die_errno("Failed to lock ref for update");
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}
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if (reflog)
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log_all_ref_updates = 1;
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if (forcing)
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snprintf(msg, sizeof msg, "branch: Reset to %s",
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start_name);
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else if (!dont_change_ref)
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snprintf(msg, sizeof msg, "branch: Created from %s",
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start_name);
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if (real_ref && track)
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setup_tracking(name, real_ref, track);
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if (!dont_change_ref)
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if (write_ref_sha1(lock, sha1, msg) < 0)
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die_errno("Failed to write ref");
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strbuf_release(&ref);
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free(real_ref);
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}
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void remove_branch_state(void)
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{
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unlink(git_path("CHERRY_PICK_HEAD"));
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unlink(git_path("MERGE_HEAD"));
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unlink(git_path("MERGE_RR"));
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unlink(git_path("MERGE_MSG"));
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unlink(git_path("MERGE_MODE"));
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unlink(git_path("SQUASH_MSG"));
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}
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