repository: drop `the_index` variable

[alt-git.git] / builtin / worktree.c

#include "builtin.h"
#include "abspath.h"
#include "advice.h"
#include "checkout.h"
#include "config.h"
#include "copy.h"
#include "dir.h"
#include "environment.h"
#include "gettext.h"
#include "hex.h"
#include "object-file.h"
#include "object-name.h"
#include "parse-options.h"
#include "path.h"
#include "strvec.h"
#include "branch.h"
#include "read-cache-ll.h"
#include "refs.h"
#include "remote.h"
#include "repository.h"
#include "run-command.h"
#include "hook.h"
#include "sigchain.h"
#include "submodule.h"
#include "utf8.h"
#include "worktree.h"
#include "quote.h"

#define BUILTIN_WORKTREE_ADD_USAGE \
        N_("git worktree add [-f] [--detach] [--checkout] [--lock [--reason <string>]]\n" \
           "                 [--orphan] [(-b | -B) <new-branch>] <path> [<commit-ish>]")

#define BUILTIN_WORKTREE_LIST_USAGE \
        N_("git worktree list [-v | --porcelain [-z]]")
#define BUILTIN_WORKTREE_LOCK_USAGE \
        N_("git worktree lock [--reason <string>] <worktree>")
#define BUILTIN_WORKTREE_MOVE_USAGE \
        N_("git worktree move <worktree> <new-path>")
#define BUILTIN_WORKTREE_PRUNE_USAGE \
        N_("git worktree prune [-n] [-v] [--expire <expire>]")
#define BUILTIN_WORKTREE_REMOVE_USAGE \
        N_("git worktree remove [-f] <worktree>")
#define BUILTIN_WORKTREE_REPAIR_USAGE \
        N_("git worktree repair [<path>...]")
#define BUILTIN_WORKTREE_UNLOCK_USAGE \
        N_("git worktree unlock <worktree>")

#define WORKTREE_ADD_DWIM_ORPHAN_INFER_TEXT \
        _("No possible source branch, inferring '--orphan'")

#define WORKTREE_ADD_ORPHAN_WITH_DASH_B_HINT_TEXT \
        _("If you meant to create a worktree containing a new unborn branch\n" \
        "(branch with no commits) for this repository, you can do so\n" \
        "using the --orphan flag:\n" \
        "\n" \
        "    git worktree add --orphan -b %s %s\n")

#define WORKTREE_ADD_ORPHAN_NO_DASH_B_HINT_TEXT \
        _("If you meant to create a worktree containing a new unborn branch\n" \
        "(branch with no commits) for this repository, you can do so\n" \
        "using the --orphan flag:\n" \
        "\n" \
        "    git worktree add --orphan %s\n")

static const char * const git_worktree_usage[] = {
        BUILTIN_WORKTREE_ADD_USAGE,
        BUILTIN_WORKTREE_LIST_USAGE,
        BUILTIN_WORKTREE_LOCK_USAGE,
        BUILTIN_WORKTREE_MOVE_USAGE,
        BUILTIN_WORKTREE_PRUNE_USAGE,
        BUILTIN_WORKTREE_REMOVE_USAGE,
        BUILTIN_WORKTREE_REPAIR_USAGE,
        BUILTIN_WORKTREE_UNLOCK_USAGE,
        NULL
};

static const char * const git_worktree_add_usage[] = {
        BUILTIN_WORKTREE_ADD_USAGE,
        NULL,
};

static const char * const git_worktree_list_usage[] = {
        BUILTIN_WORKTREE_LIST_USAGE,
        NULL
};

static const char * const git_worktree_lock_usage[] = {
        BUILTIN_WORKTREE_LOCK_USAGE,
        NULL
};

static const char * const git_worktree_move_usage[] = {
        BUILTIN_WORKTREE_MOVE_USAGE,
        NULL
};

static const char * const git_worktree_prune_usage[] = {
        BUILTIN_WORKTREE_PRUNE_USAGE,
        NULL
};

static const char * const git_worktree_remove_usage[] = {
        BUILTIN_WORKTREE_REMOVE_USAGE,
        NULL
};

static const char * const git_worktree_repair_usage[] = {
        BUILTIN_WORKTREE_REPAIR_USAGE,
        NULL
};

static const char * const git_worktree_unlock_usage[] = {
        BUILTIN_WORKTREE_UNLOCK_USAGE,
        NULL
};

struct add_opts {
        int force;
        int detach;
        int quiet;
        int checkout;
        int orphan;
        const char *keep_locked;
};

static int show_only;
static int verbose;
static int guess_remote;
static timestamp_t expire;

static int git_worktree_config(const char *var, const char *value,
                               const struct config_context *ctx, void *cb)
{
        if (!strcmp(var, "worktree.guessremote")) {
                guess_remote = git_config_bool(var, value);
                return 0;
        }

        return git_default_config(var, value, ctx, cb);
}

static int delete_git_dir(const char *id)
{
        struct strbuf sb = STRBUF_INIT;
        int ret;

        strbuf_addstr(&sb, git_common_path("worktrees/%s", id));
        ret = remove_dir_recursively(&sb, 0);
        if (ret < 0 && errno == ENOTDIR)
                ret = unlink(sb.buf);
        if (ret)
                error_errno(_("failed to delete '%s'"), sb.buf);
        strbuf_release(&sb);
        return ret;
}

static void delete_worktrees_dir_if_empty(void)
{
        rmdir(git_path("worktrees")); /* ignore failed removal */
}

static void prune_worktree(const char *id, const char *reason)
{
        if (show_only || verbose)
                fprintf_ln(stderr, _("Removing %s/%s: %s"), "worktrees", id, reason);
        if (!show_only)
                delete_git_dir(id);
}

static int prune_cmp(const void *a, const void *b)
{
        const struct string_list_item *x = a;
        const struct string_list_item *y = b;
        int c;

        if ((c = fspathcmp(x->string, y->string)))
            return c;
        /*
         * paths same; prune_dupes() removes all but the first worktree entry
         * having the same path, so sort main worktree ('util' is NULL) above
         * linked worktrees ('util' not NULL) since main worktree can't be
         * removed
         */
        if (!x->util)
                return -1;
        if (!y->util)
                return 1;
        /* paths same; sort by .git/worktrees/<id> */
        return strcmp(x->util, y->util);
}

static void prune_dups(struct string_list *l)
{
        int i;

        QSORT(l->items, l->nr, prune_cmp);
        for (i = 1; i < l->nr; i++) {
                if (!fspathcmp(l->items[i].string, l->items[i - 1].string))
                        prune_worktree(l->items[i].util, "duplicate entry");
        }
}

static void prune_worktrees(void)
{
        struct strbuf reason = STRBUF_INIT;
        struct strbuf main_path = STRBUF_INIT;
        struct string_list kept = STRING_LIST_INIT_DUP;
        DIR *dir = opendir(git_path("worktrees"));
        struct dirent *d;
        if (!dir)
                return;
        while ((d = readdir_skip_dot_and_dotdot(dir)) != NULL) {
                char *path;
                strbuf_reset(&reason);
                if (should_prune_worktree(d->d_name, &reason, &path, expire))
                        prune_worktree(d->d_name, reason.buf);
                else if (path)
                        string_list_append_nodup(&kept, path)->util = xstrdup(d->d_name);
        }
        closedir(dir);

        strbuf_add_absolute_path(&main_path, get_git_common_dir());
        /* massage main worktree absolute path to match 'gitdir' content */
        strbuf_strip_suffix(&main_path, "/.");
        string_list_append_nodup(&kept, strbuf_detach(&main_path, NULL));
        prune_dups(&kept);
        string_list_clear(&kept, 1);

        if (!show_only)
                delete_worktrees_dir_if_empty();
        strbuf_release(&reason);
}

static int prune(int ac, const char **av, const char *prefix)
{
        struct option options[] = {
                OPT__DRY_RUN(&show_only, N_("do not remove, show only")),
                OPT__VERBOSE(&verbose, N_("report pruned working trees")),
                OPT_EXPIRY_DATE(0, "expire", &expire,
                                N_("expire working trees older than <time>")),
                OPT_END()
        };

        expire = TIME_MAX;
        ac = parse_options(ac, av, prefix, options, git_worktree_prune_usage,
                           0);
        if (ac)
                usage_with_options(git_worktree_prune_usage, options);
        prune_worktrees();
        return 0;
}

static char *junk_work_tree;
static char *junk_git_dir;
static int is_junk;
static pid_t junk_pid;

static void remove_junk(void)
{
        struct strbuf sb = STRBUF_INIT;
        if (!is_junk || getpid() != junk_pid)
                return;
        if (junk_git_dir) {
                strbuf_addstr(&sb, junk_git_dir);
                remove_dir_recursively(&sb, 0);
                strbuf_reset(&sb);
        }
        if (junk_work_tree) {
                strbuf_addstr(&sb, junk_work_tree);
                remove_dir_recursively(&sb, 0);
        }
        strbuf_release(&sb);
}

static void remove_junk_on_signal(int signo)
{
        remove_junk();
        sigchain_pop(signo);
        raise(signo);
}

static const char *worktree_basename(const char *path, int *olen)
{
        const char *name;
        int len;

        len = strlen(path);
        while (len && is_dir_sep(path[len - 1]))
                len--;

        for (name = path + len - 1; name > path; name--)
                if (is_dir_sep(*name)) {
                        name++;
                        break;
                }

        *olen = len;
        return name;
}

/* check that path is viable location for worktree */
static void check_candidate_path(const char *path,
                                 int force,
                                 struct worktree **worktrees,
                                 const char *cmd)
{
        struct worktree *wt;
        int locked;

        if (file_exists(path) && !is_empty_dir(path))
                die(_("'%s' already exists"), path);

        wt = find_worktree_by_path(worktrees, path);
        if (!wt)
                return;

        locked = !!worktree_lock_reason(wt);
        if ((!locked && force) || (locked && force > 1)) {
                if (delete_git_dir(wt->id))
                    die(_("unusable worktree destination '%s'"), path);
                return;
        }

        if (locked)
                die(_("'%s' is a missing but locked worktree;\nuse '%s -f -f' to override, or 'unlock' and 'prune' or 'remove' to clear"), path, cmd);
        else
                die(_("'%s' is a missing but already registered worktree;\nuse '%s -f' to override, or 'prune' or 'remove' to clear"), path, cmd);
}

static void copy_sparse_checkout(const char *worktree_git_dir)
{
        char *from_file = git_pathdup("info/sparse-checkout");
        char *to_file = xstrfmt("%s/info/sparse-checkout", worktree_git_dir);

        if (file_exists(from_file)) {
                if (safe_create_leading_directories(to_file) ||
                        copy_file(to_file, from_file, 0666))
                        error(_("failed to copy '%s' to '%s'; sparse-checkout may not work correctly"),
                                from_file, to_file);
        }

        free(from_file);
        free(to_file);
}

static void copy_filtered_worktree_config(const char *worktree_git_dir)
{
        char *from_file = git_pathdup("config.worktree");
        char *to_file = xstrfmt("%s/config.worktree", worktree_git_dir);

        if (file_exists(from_file)) {
                struct config_set cs = { { 0 } };
                int bare;

                if (safe_create_leading_directories(to_file) ||
                        copy_file(to_file, from_file, 0666)) {
                        error(_("failed to copy worktree config from '%s' to '%s'"),
                                from_file, to_file);
                        goto worktree_copy_cleanup;
                }

                git_configset_init(&cs);
                git_configset_add_file(&cs, from_file);

                if (!git_configset_get_bool(&cs, "core.bare", &bare) &&
                        bare &&
                        git_config_set_multivar_in_file_gently(
                                to_file, "core.bare", NULL, "true", NULL, 0))
                        error(_("failed to unset '%s' in '%s'"),
                                "core.bare", to_file);
                if (!git_configset_get(&cs, "core.worktree") &&
                        git_config_set_in_file_gently(to_file,
                                                        "core.worktree", NULL, NULL))
                        error(_("failed to unset '%s' in '%s'"),
                                "core.worktree", to_file);

                git_configset_clear(&cs);
        }

worktree_copy_cleanup:
        free(from_file);
        free(to_file);
}

static int checkout_worktree(const struct add_opts *opts,
                             struct strvec *child_env)
{
        struct child_process cp = CHILD_PROCESS_INIT;
        cp.git_cmd = 1;
        strvec_pushl(&cp.args, "reset", "--hard", "--no-recurse-submodules", NULL);
        if (opts->quiet)
                strvec_push(&cp.args, "--quiet");
        strvec_pushv(&cp.env, child_env->v);
        return run_command(&cp);
}

static int make_worktree_orphan(const char * ref, const struct add_opts *opts,
                                struct strvec *child_env)
{
        struct strbuf symref = STRBUF_INIT;
        struct child_process cp = CHILD_PROCESS_INIT;

        validate_new_branchname(ref, &symref, 0);
        strvec_pushl(&cp.args, "symbolic-ref", "HEAD", symref.buf, NULL);
        if (opts->quiet)
                strvec_push(&cp.args, "--quiet");
        strvec_pushv(&cp.env, child_env->v);
        strbuf_release(&symref);
        cp.git_cmd = 1;
        return run_command(&cp);
}

static int add_worktree(const char *path, const char *refname,
                        const struct add_opts *opts)
{
        struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
        struct strbuf sb = STRBUF_INIT, realpath = STRBUF_INIT;
        const char *name;
        struct strvec child_env = STRVEC_INIT;
        unsigned int counter = 0;
        int len, ret;
        struct strbuf symref = STRBUF_INIT;
        struct commit *commit = NULL;
        int is_branch = 0;
        struct strbuf sb_name = STRBUF_INIT;
        struct worktree **worktrees, *wt = NULL;
        struct ref_store *wt_refs;

        worktrees = get_worktrees();
        check_candidate_path(path, opts->force, worktrees, "add");
        free_worktrees(worktrees);
        worktrees = NULL;

        /* is 'refname' a branch or commit? */
        if (!opts->detach && !strbuf_check_branch_ref(&symref, refname) &&
            ref_exists(symref.buf)) {
                is_branch = 1;
                if (!opts->force)
                        die_if_checked_out(symref.buf, 0);
        }
        commit = lookup_commit_reference_by_name(refname);
        if (!commit && !opts->orphan)
                die(_("invalid reference: %s"), refname);

        name = worktree_basename(path, &len);
        strbuf_add(&sb, name, path + len - name);
        sanitize_refname_component(sb.buf, &sb_name);
        if (!sb_name.len)
                BUG("How come '%s' becomes empty after sanitization?", sb.buf);
        strbuf_reset(&sb);
        name = sb_name.buf;
        git_path_buf(&sb_repo, "worktrees/%s", name);
        len = sb_repo.len;
        if (safe_create_leading_directories_const(sb_repo.buf))
                die_errno(_("could not create leading directories of '%s'"),
                          sb_repo.buf);

        while (mkdir(sb_repo.buf, 0777)) {
                counter++;
                if ((errno != EEXIST) || !counter /* overflow */)
                        die_errno(_("could not create directory of '%s'"),
                                  sb_repo.buf);
                strbuf_setlen(&sb_repo, len);
                strbuf_addf(&sb_repo, "%d", counter);
        }
        name = strrchr(sb_repo.buf, '/') + 1;

        junk_pid = getpid();
        atexit(remove_junk);
        sigchain_push_common(remove_junk_on_signal);

        junk_git_dir = xstrdup(sb_repo.buf);
        is_junk = 1;

        /*
         * lock the incomplete repo so prune won't delete it, unlock
         * after the preparation is over.
         */
        strbuf_addf(&sb, "%s/locked", sb_repo.buf);
        if (opts->keep_locked)
                write_file(sb.buf, "%s", opts->keep_locked);
        else
                write_file(sb.buf, _("initializing"));

        strbuf_addf(&sb_git, "%s/.git", path);
        if (safe_create_leading_directories_const(sb_git.buf))
                die_errno(_("could not create leading directories of '%s'"),
                          sb_git.buf);
        junk_work_tree = xstrdup(path);

        strbuf_reset(&sb);
        strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
        strbuf_realpath(&realpath, sb_git.buf, 1);
        write_file(sb.buf, "%s", realpath.buf);
        strbuf_realpath(&realpath, get_git_common_dir(), 1);
        write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
                   realpath.buf, name);
        strbuf_reset(&sb);
        strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
        write_file(sb.buf, "../..");

        /*
         * Set up the ref store of the worktree and create the HEAD reference.
         */
        wt = get_linked_worktree(name, 1);
        if (!wt) {
                ret = error(_("could not find created worktree '%s'"), name);
                goto done;
        }
        wt_refs = get_worktree_ref_store(wt);

        ret = refs_init_db(wt_refs, REFS_INIT_DB_IS_WORKTREE, &sb);
        if (ret)
                goto done;

        if (!is_branch && commit)
                ret = refs_update_ref(wt_refs, NULL, "HEAD", &commit->object.oid,
                                      NULL, 0, UPDATE_REFS_MSG_ON_ERR);
        else
                ret = refs_create_symref(wt_refs, "HEAD", symref.buf, NULL);
        if (ret)
                goto done;

        /*
         * If the current worktree has sparse-checkout enabled, then copy
         * the sparse-checkout patterns from the current worktree.
         */
        if (core_apply_sparse_checkout)
                copy_sparse_checkout(sb_repo.buf);

        /*
         * If we are using worktree config, then copy all current config
         * values from the current worktree into the new one, that way the
         * new worktree behaves the same as this one.
         */
        if (the_repository->repository_format_worktree_config)
                copy_filtered_worktree_config(sb_repo.buf);

        strvec_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
        strvec_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);

        if (opts->orphan &&
            (ret = make_worktree_orphan(refname, opts, &child_env)))
                goto done;

        if (opts->checkout &&
            (ret = checkout_worktree(opts, &child_env)))
                goto done;

        is_junk = 0;
        FREE_AND_NULL(junk_work_tree);
        FREE_AND_NULL(junk_git_dir);

done:
        if (ret || !opts->keep_locked) {
                strbuf_reset(&sb);
                strbuf_addf(&sb, "%s/locked", sb_repo.buf);
                unlink_or_warn(sb.buf);
        }

        /*
         * Hook failure does not warrant worktree deletion, so run hook after
         * is_junk is cleared, but do return appropriate code when hook fails.
         */
        if (!ret && opts->checkout && !opts->orphan) {
                struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;

                strvec_pushl(&opt.env, "GIT_DIR", "GIT_WORK_TREE", NULL);
                strvec_pushl(&opt.args,
                             oid_to_hex(null_oid()),
                             oid_to_hex(&commit->object.oid),
                             "1",
                             NULL);
                opt.dir = path;

                ret = run_hooks_opt("post-checkout", &opt);
        }

        strvec_clear(&child_env);
        strbuf_release(&sb);
        strbuf_release(&symref);
        strbuf_release(&sb_repo);
        strbuf_release(&sb_git);
        strbuf_release(&sb_name);
        strbuf_release(&realpath);
        free_worktree(wt);
        return ret;
}

static void print_preparing_worktree_line(int detach,
                                          const char *branch,
                                          const char *new_branch,
                                          int force_new_branch)
{
        if (force_new_branch) {
                struct commit *commit = lookup_commit_reference_by_name(new_branch);
                if (!commit)
                        fprintf_ln(stderr, _("Preparing worktree (new branch '%s')"), new_branch);
                else
                        fprintf_ln(stderr, _("Preparing worktree (resetting branch '%s'; was at %s)"),
                                  new_branch,
                                  repo_find_unique_abbrev(the_repository, &commit->object.oid, DEFAULT_ABBREV));
        } else if (new_branch) {
                fprintf_ln(stderr, _("Preparing worktree (new branch '%s')"), new_branch);
        } else {
                struct strbuf s = STRBUF_INIT;
                if (!detach && !strbuf_check_branch_ref(&s, branch) &&
                    ref_exists(s.buf))
                        fprintf_ln(stderr, _("Preparing worktree (checking out '%s')"),
                                  branch);
                else {
                        struct commit *commit = lookup_commit_reference_by_name(branch);
                        if (!commit)
                                BUG(_("unreachable: invalid reference: %s"), branch);
                        fprintf_ln(stderr, _("Preparing worktree (detached HEAD %s)"),
                                  repo_find_unique_abbrev(the_repository, &commit->object.oid, DEFAULT_ABBREV));
                }
                strbuf_release(&s);
        }
}

/**
 * Callback to short circuit iteration over refs on the first reference
 * corresponding to a valid oid.
 *
 * Returns 0 on failure and non-zero on success.
 */
static int first_valid_ref(const char *refname UNUSED,
                           const struct object_id *oid UNUSED,
                           int flags UNUSED,
                           void *cb_data UNUSED)
{
        return 1;
}

/**
 * Verifies HEAD and determines whether there exist any valid local references.
 *
 * - Checks whether HEAD points to a valid reference.
 *
 * - Checks whether any valid local branches exist.
 *
 * - Emits a warning if there exist any valid branches but HEAD does not point
 *   to a valid reference.
 *
 * Returns 1 if any of the previous checks are true, otherwise returns 0.
 */
static int can_use_local_refs(const struct add_opts *opts)
{
        if (head_ref(first_valid_ref, NULL)) {
                return 1;
        } else if (for_each_branch_ref(first_valid_ref, NULL)) {
                if (!opts->quiet) {
                        struct strbuf path = STRBUF_INIT;
                        struct strbuf contents = STRBUF_INIT;

                        strbuf_add_real_path(&path, get_worktree_git_dir(NULL));
                        strbuf_addstr(&path, "/HEAD");
                        strbuf_read_file(&contents, path.buf, 64);
                        strbuf_stripspace(&contents, NULL);
                        strbuf_strip_suffix(&contents, "\n");

                        warning(_("HEAD points to an invalid (or orphaned) reference.\n"
                                  "HEAD path: '%s'\n"
                                  "HEAD contents: '%s'"),
                                  path.buf, contents.buf);
                        strbuf_release(&path);
                        strbuf_release(&contents);
                }
                return 1;
        }
        return 0;
}

/**
 * Reports whether the necessary flags were set and whether the repository has
 * remote references to attempt DWIM tracking of upstream branches.
 *
 * 1. Checks that `--guess-remote` was used or `worktree.guessRemote = true`.
 *
 * 2. Checks whether any valid remote branches exist.
 *
 * 3. Checks that there exists at least one remote and emits a warning/error
 *    if both checks 1. and 2. are false (can be bypassed with `--force`).
 *
 * Returns 1 if checks 1. and 2. are true, otherwise 0.
 */
static int can_use_remote_refs(const struct add_opts *opts)
{
        if (!guess_remote) {
                return 0;
        } else if (for_each_remote_ref(first_valid_ref, NULL)) {
                return 1;
        } else if (!opts->force && remote_get(NULL)) {
                die(_("No local or remote refs exist despite at least one remote\n"
                      "present, stopping; use 'add -f' to override or fetch a remote first"));
        }
        return 0;
}

/**
 * Determines whether `--orphan` should be inferred in the evaluation of
 * `worktree add path/` or `worktree add -b branch path/` and emits an error
 * if the supplied arguments would produce an illegal combination when the
 * `--orphan` flag is included.
 *
 * `opts` and `opt_track` contain the other options & flags supplied to the
 * command.
 *
 * remote determines whether to check `can_use_remote_refs()` or not. This
 * is primarily to differentiate between the basic `add` DWIM and `add -b`.
 *
 * Returns 1 when inferring `--orphan`, 0 otherwise, and emits an error when
 * `--orphan` is inferred but doing so produces an illegal combination of
 * options and flags. Additionally produces an error when remote refs are
 * checked and the repo is in a state that looks like the user added a remote
 * but forgot to fetch (and did not override the warning with -f).
 */
static int dwim_orphan(const struct add_opts *opts, int opt_track, int remote)
{
        if (can_use_local_refs(opts)) {
                return 0;
        } else if (remote && can_use_remote_refs(opts)) {
                return 0;
        } else if (!opts->quiet) {
                fprintf_ln(stderr, WORKTREE_ADD_DWIM_ORPHAN_INFER_TEXT);
        }

        if (opt_track) {
                die(_("options '%s' and '%s' cannot be used together"),
                    "--orphan", "--track");
        } else if (!opts->checkout) {
                die(_("options '%s' and '%s' cannot be used together"),
                    "--orphan", "--no-checkout");
        }
        return 1;
}

static const char *dwim_branch(const char *path, const char **new_branch)
{
        int n;
        int branch_exists;
        const char *s = worktree_basename(path, &n);
        const char *branchname = xstrndup(s, n);
        struct strbuf ref = STRBUF_INIT;

        UNLEAK(branchname);

        branch_exists = !strbuf_check_branch_ref(&ref, branchname) &&
                        ref_exists(ref.buf);
        strbuf_release(&ref);
        if (branch_exists)
                return branchname;

        *new_branch = branchname;
        if (guess_remote) {
                struct object_id oid;
                const char *remote =
                        unique_tracking_name(*new_branch, &oid, NULL);
                return remote;
        }
        return NULL;
}

static int add(int ac, const char **av, const char *prefix)
{
        struct add_opts opts;
        const char *new_branch_force = NULL;
        char *path;
        const char *branch;
        const char *new_branch = NULL;
        const char *opt_track = NULL;
        const char *lock_reason = NULL;
        int keep_locked = 0;
        int used_new_branch_options;
        struct option options[] = {
                OPT__FORCE(&opts.force,
                           N_("checkout <branch> even if already checked out in other worktree"),
                           PARSE_OPT_NOCOMPLETE),
                OPT_STRING('b', NULL, &new_branch, N_("branch"),
                           N_("create a new branch")),
                OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
                           N_("create or reset a branch")),
                OPT_BOOL(0, "orphan", &opts.orphan, N_("create unborn branch")),
                OPT_BOOL('d', "detach", &opts.detach, N_("detach HEAD at named commit")),
                OPT_BOOL(0, "checkout", &opts.checkout, N_("populate the new working tree")),
                OPT_BOOL(0, "lock", &keep_locked, N_("keep the new working tree locked")),
                OPT_STRING(0, "reason", &lock_reason, N_("string"),
                           N_("reason for locking")),
                OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
                OPT_PASSTHRU(0, "track", &opt_track, NULL,
                             N_("set up tracking mode (see git-branch(1))"),
                             PARSE_OPT_NOARG | PARSE_OPT_OPTARG),
                OPT_BOOL(0, "guess-remote", &guess_remote,
                         N_("try to match the new branch name with a remote-tracking branch")),
                OPT_END()
        };
        int ret;

        memset(&opts, 0, sizeof(opts));
        opts.checkout = 1;
        ac = parse_options(ac, av, prefix, options, git_worktree_add_usage, 0);
        if (!!opts.detach + !!new_branch + !!new_branch_force > 1)
                die(_("options '%s', '%s', and '%s' cannot be used together"), "-b", "-B", "--detach");
        if (opts.detach && opts.orphan)
                die(_("options '%s' and '%s' cannot be used together"),
                    "--orphan", "--detach");
        if (opts.orphan && opt_track)
                die(_("options '%s' and '%s' cannot be used together"),
                    "--orphan", "--track");
        if (opts.orphan && !opts.checkout)
                die(_("options '%s' and '%s' cannot be used together"),
                    "--orphan", "--no-checkout");
        if (opts.orphan && ac == 2)
                die(_("option '%s' and commit-ish cannot be used together"),
                    "--orphan");
        if (lock_reason && !keep_locked)
                die(_("the option '%s' requires '%s'"), "--reason", "--lock");
        if (lock_reason)
                opts.keep_locked = lock_reason;
        else if (keep_locked)
                opts.keep_locked = _("added with --lock");

        if (ac < 1 || ac > 2)
                usage_with_options(git_worktree_add_usage, options);

        path = prefix_filename(prefix, av[0]);
        branch = ac < 2 ? "HEAD" : av[1];
        used_new_branch_options = new_branch || new_branch_force;

        if (!strcmp(branch, "-"))
                branch = "@{-1}";

        if (new_branch_force) {
                struct strbuf symref = STRBUF_INIT;

                new_branch = new_branch_force;

                if (!opts.force &&
                    !strbuf_check_branch_ref(&symref, new_branch) &&
                    ref_exists(symref.buf))
                        die_if_checked_out(symref.buf, 0);
                strbuf_release(&symref);
        }

        if (opts.orphan && !new_branch) {
                int n;
                const char *s = worktree_basename(path, &n);
                new_branch = xstrndup(s, n);
        } else if (opts.orphan) {
                ; /* no-op */
        } else if (opts.detach) {
                /* Check HEAD */
                if (!strcmp(branch, "HEAD"))
                        can_use_local_refs(&opts);
        } else if (ac < 2 && new_branch) {
                /* DWIM: Infer --orphan when repo has no refs. */
                opts.orphan = dwim_orphan(&opts, !!opt_track, 0);
        } else if (ac < 2) {
                /* DWIM: Guess branch name from path. */
                const char *s = dwim_branch(path, &new_branch);
                if (s)
                        branch = s;

                /* DWIM: Infer --orphan when repo has no refs. */
                opts.orphan = (!s) && dwim_orphan(&opts, !!opt_track, 1);
        } else if (ac == 2) {
                struct object_id oid;
                struct commit *commit;
                const char *remote;

                commit = lookup_commit_reference_by_name(branch);
                if (!commit) {
                        remote = unique_tracking_name(branch, &oid, NULL);
                        if (remote) {
                                new_branch = branch;
                                branch = remote;
                        }
                }

                if (!strcmp(branch, "HEAD"))
                        can_use_local_refs(&opts);

        }

        if (!opts.orphan && !lookup_commit_reference_by_name(branch)) {
                int attempt_hint = !opts.quiet && (ac < 2);
                if (attempt_hint && used_new_branch_options) {
                        advise_if_enabled(ADVICE_WORKTREE_ADD_ORPHAN,
                                WORKTREE_ADD_ORPHAN_WITH_DASH_B_HINT_TEXT,
                                new_branch, path);
                } else if (attempt_hint) {
                        advise_if_enabled(ADVICE_WORKTREE_ADD_ORPHAN,
                                WORKTREE_ADD_ORPHAN_NO_DASH_B_HINT_TEXT, path);
                }
                die(_("invalid reference: %s"), branch);
        }

        if (!opts.quiet)
                print_preparing_worktree_line(opts.detach, branch, new_branch, !!new_branch_force);

        if (opts.orphan) {
                branch = new_branch;
        } else if (new_branch) {
                struct child_process cp = CHILD_PROCESS_INIT;
                cp.git_cmd = 1;
                strvec_push(&cp.args, "branch");
                if (new_branch_force)
                        strvec_push(&cp.args, "--force");
                if (opts.quiet)
                        strvec_push(&cp.args, "--quiet");
                strvec_push(&cp.args, new_branch);
                strvec_push(&cp.args, branch);
                if (opt_track)
                        strvec_push(&cp.args, opt_track);
                if (run_command(&cp))
                        return -1;
                branch = new_branch;
        } else if (opt_track) {
                die(_("--[no-]track can only be used if a new branch is created"));
        }

        ret = add_worktree(path, branch, &opts);
        free(path);
        return ret;
}

static void show_worktree_porcelain(struct worktree *wt, int line_terminator)
{
        const char *reason;

        printf("worktree %s%c", wt->path, line_terminator);
        if (wt->is_bare)
                printf("bare%c", line_terminator);
        else {
                printf("HEAD %s%c", oid_to_hex(&wt->head_oid), line_terminator);
                if (wt->is_detached)
                        printf("detached%c", line_terminator);
                else if (wt->head_ref)
                        printf("branch %s%c", wt->head_ref, line_terminator);
        }

        reason = worktree_lock_reason(wt);
        if (reason) {
                fputs("locked", stdout);
                if (*reason) {
                        fputc(' ', stdout);
                        write_name_quoted(reason, stdout, line_terminator);
                } else {
                        fputc(line_terminator, stdout);
                }
        }

        reason = worktree_prune_reason(wt, expire);
        if (reason)
                printf("prunable %s%c", reason, line_terminator);

        fputc(line_terminator, stdout);
}

static void show_worktree(struct worktree *wt, int path_maxlen, int abbrev_len)
{
        struct strbuf sb = STRBUF_INIT;
        int cur_path_len = strlen(wt->path);
        int path_adj = cur_path_len - utf8_strwidth(wt->path);
        const char *reason;

        strbuf_addf(&sb, "%-*s ", 1 + path_maxlen + path_adj, wt->path);
        if (wt->is_bare)
                strbuf_addstr(&sb, "(bare)");
        else {
                strbuf_addf(&sb, "%-*s ", abbrev_len,
                                repo_find_unique_abbrev(the_repository, &wt->head_oid, DEFAULT_ABBREV));
                if (wt->is_detached)
                        strbuf_addstr(&sb, "(detached HEAD)");
                else if (wt->head_ref) {
                        char *ref = shorten_unambiguous_ref(wt->head_ref, 0);
                        strbuf_addf(&sb, "[%s]", ref);
                        free(ref);
                } else
                        strbuf_addstr(&sb, "(error)");
        }

        reason = worktree_lock_reason(wt);
        if (verbose && reason && *reason)
                strbuf_addf(&sb, "\n\tlocked: %s", reason);
        else if (reason)
                strbuf_addstr(&sb, " locked");

        reason = worktree_prune_reason(wt, expire);
        if (verbose && reason)
                strbuf_addf(&sb, "\n\tprunable: %s", reason);
        else if (reason)
                strbuf_addstr(&sb, " prunable");

        printf("%s\n", sb.buf);
        strbuf_release(&sb);
}

static void measure_widths(struct worktree **wt, int *abbrev, int *maxlen)
{
        int i;

        for (i = 0; wt[i]; i++) {
                int sha1_len;
                int path_len = strlen(wt[i]->path);

                if (path_len > *maxlen)
                        *maxlen = path_len;
                sha1_len = strlen(repo_find_unique_abbrev(the_repository, &wt[i]->head_oid, *abbrev));
                if (sha1_len > *abbrev)
                        *abbrev = sha1_len;
        }
}

static int pathcmp(const void *a_, const void *b_)
{
        const struct worktree *const *a = a_;
        const struct worktree *const *b = b_;
        return fspathcmp((*a)->path, (*b)->path);
}

static void pathsort(struct worktree **wt)
{
        int n = 0;
        struct worktree **p = wt;

        while (*p++)
                n++;
        QSORT(wt, n, pathcmp);
}

static int list(int ac, const char **av, const char *prefix)
{
        int porcelain = 0;
        int line_terminator = '\n';

        struct option options[] = {
                OPT_BOOL(0, "porcelain", &porcelain, N_("machine-readable output")),
                OPT__VERBOSE(&verbose, N_("show extended annotations and reasons, if available")),
                OPT_EXPIRY_DATE(0, "expire", &expire,
                                N_("add 'prunable' annotation to worktrees older than <time>")),
                OPT_SET_INT('z', NULL, &line_terminator,
                            N_("terminate records with a NUL character"), '\0'),
                OPT_END()
        };

        expire = TIME_MAX;
        ac = parse_options(ac, av, prefix, options, git_worktree_list_usage, 0);
        if (ac)
                usage_with_options(git_worktree_list_usage, options);
        else if (verbose && porcelain)
                die(_("options '%s' and '%s' cannot be used together"), "--verbose", "--porcelain");
        else if (!line_terminator && !porcelain)
                die(_("the option '%s' requires '%s'"), "-z", "--porcelain");
        else {
                struct worktree **worktrees = get_worktrees();
                int path_maxlen = 0, abbrev = DEFAULT_ABBREV, i;

                /* sort worktrees by path but keep main worktree at top */
                pathsort(worktrees + 1);

                if (!porcelain)
                        measure_widths(worktrees, &abbrev, &path_maxlen);

                for (i = 0; worktrees[i]; i++) {
                        if (porcelain)
                                show_worktree_porcelain(worktrees[i],
                                                        line_terminator);
                        else
                                show_worktree(worktrees[i], path_maxlen, abbrev);
                }
                free_worktrees(worktrees);
        }
        return 0;
}

static int lock_worktree(int ac, const char **av, const char *prefix)
{
        const char *reason = "", *old_reason;
        struct option options[] = {
                OPT_STRING(0, "reason", &reason, N_("string"),
                           N_("reason for locking")),
                OPT_END()
        };
        struct worktree **worktrees, *wt;

        ac = parse_options(ac, av, prefix, options, git_worktree_lock_usage, 0);
        if (ac != 1)
                usage_with_options(git_worktree_lock_usage, options);

        worktrees = get_worktrees();
        wt = find_worktree(worktrees, prefix, av[0]);
        if (!wt)
                die(_("'%s' is not a working tree"), av[0]);
        if (is_main_worktree(wt))
                die(_("The main working tree cannot be locked or unlocked"));

        old_reason = worktree_lock_reason(wt);
        if (old_reason) {
                if (*old_reason)
                        die(_("'%s' is already locked, reason: %s"),
                            av[0], old_reason);
                die(_("'%s' is already locked"), av[0]);
        }

        write_file(git_common_path("worktrees/%s/locked", wt->id),
                   "%s", reason);
        free_worktrees(worktrees);
        return 0;
}

static int unlock_worktree(int ac, const char **av, const char *prefix)
{
        struct option options[] = {
                OPT_END()
        };
        struct worktree **worktrees, *wt;
        int ret;

        ac = parse_options(ac, av, prefix, options, git_worktree_unlock_usage, 0);
        if (ac != 1)
                usage_with_options(git_worktree_unlock_usage, options);

        worktrees = get_worktrees();
        wt = find_worktree(worktrees, prefix, av[0]);
        if (!wt)
                die(_("'%s' is not a working tree"), av[0]);
        if (is_main_worktree(wt))
                die(_("The main working tree cannot be locked or unlocked"));
        if (!worktree_lock_reason(wt))
                die(_("'%s' is not locked"), av[0]);
        ret = unlink_or_warn(git_common_path("worktrees/%s/locked", wt->id));
        free_worktrees(worktrees);
        return ret;
}

static void validate_no_submodules(const struct worktree *wt)
{
        struct index_state istate = INDEX_STATE_INIT(the_repository);
        struct strbuf path = STRBUF_INIT;
        int i, found_submodules = 0;

        if (is_directory(worktree_git_path(wt, "modules"))) {
                /*
                 * There could be false positives, e.g. the "modules"
                 * directory exists but is empty. But it's a rare case and
                 * this simpler check is probably good enough for now.
                 */
                found_submodules = 1;
        } else if (read_index_from(&istate, worktree_git_path(wt, "index"),
                                   get_worktree_git_dir(wt)) > 0) {
                for (i = 0; i < istate.cache_nr; i++) {
                        struct cache_entry *ce = istate.cache[i];
                        int err;

                        if (!S_ISGITLINK(ce->ce_mode))
                                continue;

                        strbuf_reset(&path);
                        strbuf_addf(&path, "%s/%s", wt->path, ce->name);
                        if (!is_submodule_populated_gently(path.buf, &err))
                                continue;

                        found_submodules = 1;
                        break;
                }
        }
        discard_index(&istate);
        strbuf_release(&path);

        if (found_submodules)
                die(_("working trees containing submodules cannot be moved or removed"));
}

static int move_worktree(int ac, const char **av, const char *prefix)
{
        int force = 0;
        struct option options[] = {
                OPT__FORCE(&force,
                         N_("force move even if worktree is dirty or locked"),
                         PARSE_OPT_NOCOMPLETE),
                OPT_END()
        };
        struct worktree **worktrees, *wt;
        struct strbuf dst = STRBUF_INIT;
        struct strbuf errmsg = STRBUF_INIT;
        const char *reason = NULL;
        char *path;

        ac = parse_options(ac, av, prefix, options, git_worktree_move_usage,
                           0);
        if (ac != 2)
                usage_with_options(git_worktree_move_usage, options);

        path = prefix_filename(prefix, av[1]);
        strbuf_addstr(&dst, path);
        free(path);

        worktrees = get_worktrees();
        wt = find_worktree(worktrees, prefix, av[0]);
        if (!wt)
                die(_("'%s' is not a working tree"), av[0]);
        if (is_main_worktree(wt))
                die(_("'%s' is a main working tree"), av[0]);
        if (is_directory(dst.buf)) {
                const char *sep = find_last_dir_sep(wt->path);

                if (!sep)
                        die(_("could not figure out destination name from '%s'"),
                            wt->path);
                strbuf_trim_trailing_dir_sep(&dst);
                strbuf_addstr(&dst, sep);
        }
        check_candidate_path(dst.buf, force, worktrees, "move");

        validate_no_submodules(wt);

        if (force < 2)
                reason = worktree_lock_reason(wt);
        if (reason) {
                if (*reason)
                        die(_("cannot move a locked working tree, lock reason: %s\nuse 'move -f -f' to override or unlock first"),
                            reason);
                die(_("cannot move a locked working tree;\nuse 'move -f -f' to override or unlock first"));
        }
        if (validate_worktree(wt, &errmsg, 0))
                die(_("validation failed, cannot move working tree: %s"),
                    errmsg.buf);
        strbuf_release(&errmsg);

        if (rename(wt->path, dst.buf) == -1)
                die_errno(_("failed to move '%s' to '%s'"), wt->path, dst.buf);

        update_worktree_location(wt, dst.buf);

        strbuf_release(&dst);
        free_worktrees(worktrees);
        return 0;
}

/*
 * Note, "git status --porcelain" is used to determine if it's safe to
 * delete a whole worktree. "git status" does not ignore user
 * configuration, so if a normal "git status" shows "clean" for the
 * user, then it's ok to remove it.
 *
 * This assumption may be a bad one. We may want to ignore
 * (potentially bad) user settings and only delete a worktree when
 * it's absolutely safe to do so from _our_ point of view because we
 * know better.
 */
static void check_clean_worktree(struct worktree *wt,
                                 const char *original_path)
{
        struct child_process cp;
        char buf[1];
        int ret;

        /*
         * Until we sort this out, all submodules are "dirty" and
         * will abort this function.
         */
        validate_no_submodules(wt);

        child_process_init(&cp);
        strvec_pushf(&cp.env, "%s=%s/.git",
                     GIT_DIR_ENVIRONMENT, wt->path);
        strvec_pushf(&cp.env, "%s=%s",
                     GIT_WORK_TREE_ENVIRONMENT, wt->path);
        strvec_pushl(&cp.args, "status",
                     "--porcelain", "--ignore-submodules=none",
                     NULL);
        cp.git_cmd = 1;
        cp.dir = wt->path;
        cp.out = -1;
        ret = start_command(&cp);
        if (ret)
                die_errno(_("failed to run 'git status' on '%s'"),
                          original_path);
        ret = xread(cp.out, buf, sizeof(buf));
        if (ret)
                die(_("'%s' contains modified or untracked files, use --force to delete it"),
                    original_path);
        close(cp.out);
        ret = finish_command(&cp);
        if (ret)
                die_errno(_("failed to run 'git status' on '%s', code %d"),
                          original_path, ret);
}

static int delete_git_work_tree(struct worktree *wt)
{
        struct strbuf sb = STRBUF_INIT;
        int ret = 0;

        strbuf_addstr(&sb, wt->path);
        if (remove_dir_recursively(&sb, 0)) {
                error_errno(_("failed to delete '%s'"), sb.buf);
                ret = -1;
        }
        strbuf_release(&sb);
        return ret;
}

static int remove_worktree(int ac, const char **av, const char *prefix)
{
        int force = 0;
        struct option options[] = {
                OPT__FORCE(&force,
                         N_("force removal even if worktree is dirty or locked"),
                         PARSE_OPT_NOCOMPLETE),
                OPT_END()
        };
        struct worktree **worktrees, *wt;
        struct strbuf errmsg = STRBUF_INIT;
        const char *reason = NULL;
        int ret = 0;

        ac = parse_options(ac, av, prefix, options, git_worktree_remove_usage, 0);
        if (ac != 1)
                usage_with_options(git_worktree_remove_usage, options);

        worktrees = get_worktrees();
        wt = find_worktree(worktrees, prefix, av[0]);
        if (!wt)
                die(_("'%s' is not a working tree"), av[0]);
        if (is_main_worktree(wt))
                die(_("'%s' is a main working tree"), av[0]);
        if (force < 2)
                reason = worktree_lock_reason(wt);
        if (reason) {
                if (*reason)
                        die(_("cannot remove a locked working tree, lock reason: %s\nuse 'remove -f -f' to override or unlock first"),
                            reason);
                die(_("cannot remove a locked working tree;\nuse 'remove -f -f' to override or unlock first"));
        }
        if (validate_worktree(wt, &errmsg, WT_VALIDATE_WORKTREE_MISSING_OK))
                die(_("validation failed, cannot remove working tree: %s"),
                    errmsg.buf);
        strbuf_release(&errmsg);

        if (file_exists(wt->path)) {
                if (!force)
                        check_clean_worktree(wt, av[0]);

                ret |= delete_git_work_tree(wt);
        }
        /*
         * continue on even if ret is non-zero, there's no going back
         * from here.
         */
        ret |= delete_git_dir(wt->id);
        delete_worktrees_dir_if_empty();

        free_worktrees(worktrees);
        return ret;
}

static void report_repair(int iserr, const char *path, const char *msg, void *cb_data)
{
        if (!iserr) {
                fprintf_ln(stderr, _("repair: %s: %s"), msg, path);
        } else {
                int *exit_status = (int *)cb_data;
                fprintf_ln(stderr, _("error: %s: %s"), msg, path);
                *exit_status = 1;
        }
}

static int repair(int ac, const char **av, const char *prefix)
{
        const char **p;
        const char *self[] = { ".", NULL };
        struct option options[] = {
                OPT_END()
        };
        int rc = 0;

        ac = parse_options(ac, av, prefix, options, git_worktree_repair_usage, 0);
        p = ac > 0 ? av : self;
        for (; *p; p++)
                repair_worktree_at_path(*p, report_repair, &rc);
        repair_worktrees(report_repair, &rc);
        return rc;
}

int cmd_worktree(int ac, const char **av, const char *prefix)
{
        parse_opt_subcommand_fn *fn = NULL;
        struct option options[] = {
                OPT_SUBCOMMAND("add", &fn, add),
                OPT_SUBCOMMAND("prune", &fn, prune),
                OPT_SUBCOMMAND("list", &fn, list),
                OPT_SUBCOMMAND("lock", &fn, lock_worktree),
                OPT_SUBCOMMAND("unlock", &fn, unlock_worktree),
                OPT_SUBCOMMAND("move", &fn, move_worktree),
                OPT_SUBCOMMAND("remove", &fn, remove_worktree),
                OPT_SUBCOMMAND("repair", &fn, repair),
                OPT_END()
        };

        git_config(git_worktree_config, NULL);

        if (!prefix)
                prefix = "";

        ac = parse_options(ac, av, prefix, options, git_worktree_usage, 0);

        prepare_repo_settings(the_repository);
        the_repository->settings.command_requires_full_index = 0;

        return fn(ac, av, prefix);
}