checkout: don't require a work tree when checking out into a new one
[gitweb.git] / builtin / checkout.c
index 570bb09c4f176ff21d593361261ec008c3a89739..8c5276cf443f5d1e84cd5fd34e5f899afd3e58b6 100644 (file)
@@ -20,6 +20,7 @@
 #include "resolve-undo.h"
 #include "submodule.h"
 #include "argv-array.h"
+#include "sigchain.h"
 
 static const char * const checkout_usage[] = {
        N_("git checkout [options] <branch>"),
@@ -48,6 +49,10 @@ struct checkout_opts {
        const char *prefix;
        struct pathspec pathspec;
        struct tree *source_tree;
+
+       const char *new_worktree;
+       const char **saved_argv;
+       int new_worktree_mode;
 };
 
 static int post_checkout_hook(struct commit *old, struct commit *new,
@@ -249,6 +254,9 @@ static int checkout_paths(const struct checkout_opts *opts,
                die(_("Cannot update paths and switch to branch '%s' at the same time."),
                    opts->new_branch);
 
+       if (opts->new_worktree)
+               die(_("'%s' cannot be used with updating paths"), "--to");
+
        if (opts->patch_mode)
                return run_add_interactive(revision, "--patch=checkout",
                                           &opts->pathspec);
@@ -355,7 +363,7 @@ static int checkout_paths(const struct checkout_opts *opts,
        if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
                die(_("unable to write new index file"));
 
-       read_ref_full("HEAD", rev, 0, &flag);
+       read_ref_full("HEAD", 0, rev, &flag);
        head = lookup_commit_reference_gently(rev, 1);
 
        errs |= post_checkout_hook(head, head, 0);
@@ -423,6 +431,11 @@ struct branch_info {
        const char *name; /* The short name used */
        const char *path; /* The full name of a real branch */
        struct commit *commit; /* The named commit */
+       /*
+        * if not null the branch is detached because it's already
+        * checked out in this checkout
+        */
+       char *checkout;
 };
 
 static void setup_branch_path(struct branch_info *branch)
@@ -484,7 +497,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
                        topts.dir->flags |= DIR_SHOW_IGNORED;
                        setup_standard_excludes(topts.dir);
                }
-               tree = parse_tree_indirect(old->commit ?
+               tree = parse_tree_indirect(old->commit && !opts->new_worktree_mode ?
                                           old->commit->object.sha1 :
                                           EMPTY_TREE_SHA1_BIN);
                init_tree_desc(&trees[0], tree->buffer, tree->size);
@@ -588,18 +601,21 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
                if (opts->new_orphan_branch) {
                        if (opts->new_branch_log && !log_all_ref_updates) {
                                int temp;
-                               char log_file[PATH_MAX];
-                               char *ref_name = mkpath("refs/heads/%s", opts->new_orphan_branch);
+                               struct strbuf log_file = STRBUF_INIT;
+                               int ret;
+                               const char *ref_name;
 
+                               ref_name = mkpath("refs/heads/%s", opts->new_orphan_branch);
                                temp = log_all_ref_updates;
                                log_all_ref_updates = 1;
-                               if (log_ref_setup(ref_name, log_file, sizeof(log_file))) {
+                               ret = log_ref_setup(ref_name, &log_file);
+                               log_all_ref_updates = temp;
+                               strbuf_release(&log_file);
+                               if (ret) {
                                        fprintf(stderr, _("Can not do reflog for '%s'\n"),
                                            opts->new_orphan_branch);
-                                       log_all_ref_updates = temp;
                                        return;
                                }
-                               log_all_ref_updates = temp;
                        }
                }
                else
@@ -775,7 +791,7 @@ static int switch_branches(const struct checkout_opts *opts,
        unsigned char rev[20];
        int flag, writeout_error = 0;
        memset(&old, 0, sizeof(old));
-       old.path = path_to_free = resolve_refdup("HEAD", rev, 0, &flag);
+       old.path = path_to_free = resolve_refdup("HEAD", 0, rev, &flag);
        old.commit = lookup_commit_reference_gently(rev, 1);
        if (!(flag & REF_ISSYMREF))
                old.path = NULL;
@@ -797,7 +813,8 @@ static int switch_branches(const struct checkout_opts *opts,
                return ret;
        }
 
-       if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
+       if (!opts->quiet && !old.path && old.commit &&
+           new->commit != old.commit && !opts->new_worktree_mode)
                orphaned_commit_warning(old.commit, new->commit);
 
        update_refs_for_switch(opts, &old, new);
@@ -807,6 +824,138 @@ static int switch_branches(const struct checkout_opts *opts,
        return ret || writeout_error;
 }
 
+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 int prepare_linked_checkout(const struct checkout_opts *opts,
+                                  struct branch_info *new)
+{
+       struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
+       struct strbuf sb = STRBUF_INIT;
+       const char *path = opts->new_worktree, *name;
+       struct stat st;
+       struct child_process cp;
+       int counter = 0, len, ret;
+
+       if (!new->commit)
+               die(_("no branch specified"));
+       if (file_exists(path))
+               die(_("'%s' already exists"), path);
+
+       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;
+               }
+       strbuf_addstr(&sb_repo,
+                     git_path("worktrees/%.*s", (int)(path + len - name), 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 (!stat(sb_repo.buf, &st)) {
+               counter++;
+               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);
+
+       if (mkdir(sb_repo.buf, 0777))
+               die_errno(_("could not create directory of '%s'"), sb_repo.buf);
+       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);
+       write_file(sb.buf, 1, "initializing\n");
+
+       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);
+       write_file(sb.buf, 1, "%s\n", real_path(sb_git.buf));
+       write_file(sb_git.buf, 1, "gitdir: %s/worktrees/%s\n",
+                  real_path(get_git_common_dir()), name);
+       /*
+        * This is to keep resolve_ref() happy. We need a valid HEAD
+        * or is_git_directory() will reject the directory. Any valid
+        * value would do because this value will be ignored and
+        * replaced at the next (real) checkout.
+        */
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
+       write_file(sb.buf, 1, "%s\n", sha1_to_hex(new->commit->object.sha1));
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
+       write_file(sb.buf, 1, "../..\n");
+
+       if (!opts->quiet)
+               fprintf_ln(stderr, _("Enter %s (identifier %s)"), path, name);
+
+       setenv("GIT_CHECKOUT_NEW_WORKTREE", "1", 1);
+       setenv(GIT_DIR_ENVIRONMENT, sb_git.buf, 1);
+       setenv(GIT_WORK_TREE_ENVIRONMENT, path, 1);
+       memset(&cp, 0, sizeof(cp));
+       cp.git_cmd = 1;
+       cp.argv = opts->saved_argv;
+       ret = run_command(&cp);
+       if (!ret) {
+               is_junk = 0;
+               free(junk_work_tree);
+               free(junk_git_dir);
+               junk_work_tree = NULL;
+               junk_git_dir = NULL;
+       }
+       strbuf_reset(&sb);
+       strbuf_addf(&sb, "%s/locked", sb_repo.buf);
+       unlink_or_warn(sb.buf);
+       strbuf_release(&sb);
+       strbuf_release(&sb_repo);
+       strbuf_release(&sb_git);
+       return ret;
+}
+
 static int git_checkout_config(const char *var, const char *value, void *cb)
 {
        if (!strcmp(var, "diff.ignoresubmodules")) {
@@ -862,12 +1011,78 @@ static const char *unique_tracking_name(const char *name, unsigned char *sha1)
        return NULL;
 }
 
+static void check_linked_checkout(struct branch_info *new, const char *id)
+{
+       struct strbuf sb = STRBUF_INIT;
+       struct strbuf path = STRBUF_INIT;
+       struct strbuf gitdir = STRBUF_INIT;
+       const char *start, *end;
+
+       if (id)
+               strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);
+       else
+               strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
+
+       if (strbuf_read_file(&sb, path.buf, 0) < 0 ||
+           !skip_prefix(sb.buf, "ref:", &start))
+               goto done;
+       while (isspace(*start))
+               start++;
+       end = start;
+       while (*end && !isspace(*end))
+               end++;
+       if (strncmp(start, new->path, end - start) || new->path[end - start] != '\0')
+               goto done;
+       if (id) {
+               strbuf_reset(&path);
+               strbuf_addf(&path, "%s/worktrees/%s/gitdir", get_git_common_dir(), id);
+               if (strbuf_read_file(&gitdir, path.buf, 0) <= 0)
+                       goto done;
+               strbuf_rtrim(&gitdir);
+       } else
+               strbuf_addstr(&gitdir, get_git_common_dir());
+       die(_("'%s' is already checked out at '%s'"), new->name, gitdir.buf);
+done:
+       strbuf_release(&path);
+       strbuf_release(&sb);
+       strbuf_release(&gitdir);
+}
+
+static void check_linked_checkouts(struct branch_info *new)
+{
+       struct strbuf path = STRBUF_INIT;
+       DIR *dir;
+       struct dirent *d;
+
+       strbuf_addf(&path, "%s/worktrees", get_git_common_dir());
+       if ((dir = opendir(path.buf)) == NULL) {
+               strbuf_release(&path);
+               return;
+       }
+
+       /*
+        * $GIT_COMMON_DIR/HEAD is practically outside
+        * $GIT_DIR so resolve_ref_unsafe() won't work (it
+        * uses git_path). Parse the ref ourselves.
+        */
+       check_linked_checkout(new, NULL);
+
+       while ((d = readdir(dir)) != NULL) {
+               if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+                       continue;
+               check_linked_checkout(new, d->d_name);
+       }
+       strbuf_release(&path);
+       closedir(dir);
+}
+
 static int parse_branchname_arg(int argc, const char **argv,
                                int dwim_new_local_branch_ok,
                                struct branch_info *new,
                                struct tree **source_tree,
                                unsigned char rev[20],
-                               const char **new_branch)
+                               const char **new_branch,
+                               int force_detach)
 {
        int argcount = 0;
        unsigned char branch_rev[20];
@@ -989,6 +1204,16 @@ static int parse_branchname_arg(int argc, const char **argv,
        else
                new->path = NULL; /* not an existing branch */
 
+       if (new->path && !force_detach && !*new_branch) {
+               unsigned char sha1[20];
+               int flag;
+               char *head_ref = resolve_refdup("HEAD", 0, sha1, &flag);
+               if (head_ref &&
+                   (!(flag & REF_ISSYMREF) || strcmp(head_ref, new->path)))
+                       check_linked_checkouts(new);
+               free(head_ref);
+       }
+
        new->commit = lookup_commit_reference_gently(rev, 1);
        if (!new->commit) {
                /* not a commit */
@@ -1068,11 +1293,14 @@ static int checkout_branch(struct checkout_opts *opts,
                die(_("Cannot switch branch to a non-commit '%s'"),
                    new->name);
 
+       if (opts->new_worktree)
+               return prepare_linked_checkout(opts, new);
+
        if (!new->commit && opts->new_branch) {
                unsigned char rev[20];
                int flag;
 
-               if (!read_ref_full("HEAD", rev, 0, &flag) &&
+               if (!read_ref_full("HEAD", 0, rev, &flag) &&
                    (flag & REF_ISSYMREF) && is_null_sha1(rev))
                        return switch_unborn_to_new_branch(opts);
        }
@@ -1110,6 +1338,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                         N_("do not limit pathspecs to sparse entries only")),
                OPT_HIDDEN_BOOL(0, "guess", &dwim_new_local_branch,
                                N_("second guess 'git checkout no-such-branch'")),
+               OPT_FILENAME(0, "to", &opts.new_worktree,
+                          N_("check a branch out in a separate working directory")),
                OPT_END(),
        };
 
@@ -1118,6 +1348,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        opts.overwrite_ignore = 1;
        opts.prefix = prefix;
 
+       opts.saved_argv = xmalloc(sizeof(const char *) * (argc + 2));
+       memcpy(opts.saved_argv, argv, sizeof(const char *) * (argc + 1));
+
        gitmodules_config();
        git_config(git_checkout_config, &opts);
 
@@ -1126,6 +1359,14 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        argc = parse_options(argc, argv, prefix, options, checkout_usage,
                             PARSE_OPT_KEEP_DASHDASH);
 
+       /* recursive execution from checkout_new_worktree() */
+       opts.new_worktree_mode = getenv("GIT_CHECKOUT_NEW_WORKTREE") != NULL;
+       if (opts.new_worktree_mode)
+               opts.new_worktree = NULL;
+
+       if (!opts.new_worktree)
+               setup_work_tree();
+
        if (conflict_style) {
                opts.merge = 1; /* implied */
                git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
@@ -1150,10 +1391,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                const char *argv0 = argv[0];
                if (!argc || !strcmp(argv0, "--"))
                        die (_("--track needs a branch name"));
-               if (starts_with(argv0, "refs/"))
-                       argv0 += 5;
-               if (starts_with(argv0, "remotes/"))
-                       argv0 += 8;
+               skip_prefix(argv0, "refs/", &argv0);
+               skip_prefix(argv0, "remotes/", &argv0);
                argv0 = strchr(argv0, '/');
                if (!argv0 || !argv0[1])
                        die (_("Missing branch name; try -b"));
@@ -1182,7 +1421,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                        !opts.new_branch;
                int n = parse_branchname_arg(argc, argv, dwim_ok,
                                             &new, &opts.source_tree,
-                                            rev, &opts.new_branch);
+                                            rev, &opts.new_branch,
+                                            opts.force_detach);
                argv += n;
                argc -= n;
        }