worktree: make setup of new HEAD distinct from worktree population
[git] / builtin / worktree.c
1 #include "cache.h"
2 #include "builtin.h"
3 #include "dir.h"
4 #include "parse-options.h"
5 #include "argv-array.h"
6 #include "branch.h"
7 #include "refs.h"
8 #include "run-command.h"
9 #include "sigchain.h"
10
11 static const char * const worktree_usage[] = {
12         N_("git worktree add [<options>] <path> <branch>"),
13         N_("git worktree prune [<options>]"),
14         NULL
15 };
16
17 struct add_opts {
18         int force;
19         int detach;
20         const char *new_branch;
21         int force_new_branch;
22 };
23
24 static int show_only;
25 static int verbose;
26 static unsigned long expire;
27
28 static int prune_worktree(const char *id, struct strbuf *reason)
29 {
30         struct stat st;
31         char *path;
32         int fd, len;
33
34         if (!is_directory(git_path("worktrees/%s", id))) {
35                 strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
36                 return 1;
37         }
38         if (file_exists(git_path("worktrees/%s/locked", id)))
39                 return 0;
40         if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
41                 strbuf_addf(reason, _("Removing worktrees/%s: gitdir file does not exist"), id);
42                 return 1;
43         }
44         fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
45         if (fd < 0) {
46                 strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
47                             id, strerror(errno));
48                 return 1;
49         }
50         len = st.st_size;
51         path = xmalloc(len + 1);
52         read_in_full(fd, path, len);
53         close(fd);
54         while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
55                 len--;
56         if (!len) {
57                 strbuf_addf(reason, _("Removing worktrees/%s: invalid gitdir file"), id);
58                 free(path);
59                 return 1;
60         }
61         path[len] = '\0';
62         if (!file_exists(path)) {
63                 struct stat st_link;
64                 free(path);
65                 /*
66                  * the repo is moved manually and has not been
67                  * accessed since?
68                  */
69                 if (!stat(git_path("worktrees/%s/link", id), &st_link) &&
70                     st_link.st_nlink > 1)
71                         return 0;
72                 if (st.st_mtime <= expire) {
73                         strbuf_addf(reason, _("Removing worktrees/%s: gitdir file points to non-existent location"), id);
74                         return 1;
75                 } else {
76                         return 0;
77                 }
78         }
79         free(path);
80         return 0;
81 }
82
83 static void prune_worktrees(void)
84 {
85         struct strbuf reason = STRBUF_INIT;
86         struct strbuf path = STRBUF_INIT;
87         DIR *dir = opendir(git_path("worktrees"));
88         struct dirent *d;
89         int ret;
90         if (!dir)
91                 return;
92         while ((d = readdir(dir)) != NULL) {
93                 if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
94                         continue;
95                 strbuf_reset(&reason);
96                 if (!prune_worktree(d->d_name, &reason))
97                         continue;
98                 if (show_only || verbose)
99                         printf("%s\n", reason.buf);
100                 if (show_only)
101                         continue;
102                 strbuf_reset(&path);
103                 strbuf_addstr(&path, git_path("worktrees/%s", d->d_name));
104                 ret = remove_dir_recursively(&path, 0);
105                 if (ret < 0 && errno == ENOTDIR)
106                         ret = unlink(path.buf);
107                 if (ret)
108                         error(_("failed to remove: %s"), strerror(errno));
109         }
110         closedir(dir);
111         if (!show_only)
112                 rmdir(git_path("worktrees"));
113         strbuf_release(&reason);
114         strbuf_release(&path);
115 }
116
117 static int prune(int ac, const char **av, const char *prefix)
118 {
119         struct option options[] = {
120                 OPT__DRY_RUN(&show_only, N_("do not remove, show only")),
121                 OPT__VERBOSE(&verbose, N_("report pruned objects")),
122                 OPT_EXPIRY_DATE(0, "expire", &expire,
123                                 N_("expire objects older than <time>")),
124                 OPT_END()
125         };
126
127         expire = ULONG_MAX;
128         ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
129         if (ac)
130                 usage_with_options(worktree_usage, options);
131         prune_worktrees();
132         return 0;
133 }
134
135 static char *junk_work_tree;
136 static char *junk_git_dir;
137 static int is_junk;
138 static pid_t junk_pid;
139
140 static void remove_junk(void)
141 {
142         struct strbuf sb = STRBUF_INIT;
143         if (!is_junk || getpid() != junk_pid)
144                 return;
145         if (junk_git_dir) {
146                 strbuf_addstr(&sb, junk_git_dir);
147                 remove_dir_recursively(&sb, 0);
148                 strbuf_reset(&sb);
149         }
150         if (junk_work_tree) {
151                 strbuf_addstr(&sb, junk_work_tree);
152                 remove_dir_recursively(&sb, 0);
153         }
154         strbuf_release(&sb);
155 }
156
157 static void remove_junk_on_signal(int signo)
158 {
159         remove_junk();
160         sigchain_pop(signo);
161         raise(signo);
162 }
163
164 static const char *worktree_basename(const char *path, int *olen)
165 {
166         const char *name;
167         int len;
168
169         len = strlen(path);
170         while (len && is_dir_sep(path[len - 1]))
171                 len--;
172
173         for (name = path + len - 1; name > path; name--)
174                 if (is_dir_sep(*name)) {
175                         name++;
176                         break;
177                 }
178
179         *olen = len;
180         return name;
181 }
182
183 static int add_worktree(const char *path, const char *refname,
184                         const struct add_opts *opts)
185 {
186         struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
187         struct strbuf sb = STRBUF_INIT;
188         const char *name;
189         struct stat st;
190         struct child_process cp;
191         struct argv_array child_env = ARGV_ARRAY_INIT;
192         int counter = 0, len, ret;
193         struct strbuf symref = STRBUF_INIT;
194         struct commit *commit = NULL;
195         unsigned char rev[20];
196
197         if (file_exists(path) && !is_empty_dir(path))
198                 die(_("'%s' already exists"), path);
199
200         /* is 'refname' a branch or commit? */
201         if (opts->force_new_branch) /* definitely a branch */
202                 ;
203         else if (!opts->detach && !strbuf_check_branch_ref(&symref, refname) &&
204                  ref_exists(symref.buf)) { /* it's a branch */
205                 if (!opts->force)
206                         die_if_checked_out(symref.buf);
207         } else { /* must be a commit */
208                 commit = lookup_commit_reference_by_name(refname);
209                 if (!commit)
210                         die(_("invalid reference: %s"), refname);
211         }
212
213         name = worktree_basename(path, &len);
214         strbuf_addstr(&sb_repo,
215                       git_path("worktrees/%.*s", (int)(path + len - name), name));
216         len = sb_repo.len;
217         if (safe_create_leading_directories_const(sb_repo.buf))
218                 die_errno(_("could not create leading directories of '%s'"),
219                           sb_repo.buf);
220         while (!stat(sb_repo.buf, &st)) {
221                 counter++;
222                 strbuf_setlen(&sb_repo, len);
223                 strbuf_addf(&sb_repo, "%d", counter);
224         }
225         name = strrchr(sb_repo.buf, '/') + 1;
226
227         junk_pid = getpid();
228         atexit(remove_junk);
229         sigchain_push_common(remove_junk_on_signal);
230
231         if (mkdir(sb_repo.buf, 0777))
232                 die_errno(_("could not create directory of '%s'"), sb_repo.buf);
233         junk_git_dir = xstrdup(sb_repo.buf);
234         is_junk = 1;
235
236         /*
237          * lock the incomplete repo so prune won't delete it, unlock
238          * after the preparation is over.
239          */
240         strbuf_addf(&sb, "%s/locked", sb_repo.buf);
241         write_file(sb.buf, 1, "initializing\n");
242
243         strbuf_addf(&sb_git, "%s/.git", path);
244         if (safe_create_leading_directories_const(sb_git.buf))
245                 die_errno(_("could not create leading directories of '%s'"),
246                           sb_git.buf);
247         junk_work_tree = xstrdup(path);
248
249         strbuf_reset(&sb);
250         strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
251         write_file(sb.buf, 1, "%s\n", real_path(sb_git.buf));
252         write_file(sb_git.buf, 1, "gitdir: %s/worktrees/%s\n",
253                    real_path(get_git_common_dir()), name);
254         /*
255          * This is to keep resolve_ref() happy. We need a valid HEAD
256          * or is_git_directory() will reject the directory. Moreover, HEAD
257          * in the new worktree must resolve to the same value as HEAD in
258          * the current tree since the command invoked to populate the new
259          * worktree will be handed the branch/ref specified by the user.
260          * For instance, if the user asks for the new worktree to be based
261          * at HEAD~5, then the resolved HEAD~5 in the new worktree must
262          * match the resolved HEAD~5 in the current tree in order to match
263          * the user's expectation.
264          */
265         if (!resolve_ref_unsafe("HEAD", 0, rev, NULL))
266                 die(_("unable to resolve HEAD"));
267         strbuf_reset(&sb);
268         strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
269         write_file(sb.buf, 1, "%s\n", sha1_to_hex(rev));
270         strbuf_reset(&sb);
271         strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
272         write_file(sb.buf, 1, "../..\n");
273
274         fprintf_ln(stderr, _("Preparing %s (identifier %s)"), path, name);
275
276         setenv("GIT_CHECKOUT_NEW_WORKTREE", "1", 1);
277         argv_array_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
278         argv_array_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
279         memset(&cp, 0, sizeof(cp));
280         cp.git_cmd = 1;
281
282         if (commit)
283                 argv_array_pushl(&cp.args, "update-ref", "HEAD",
284                                  sha1_to_hex(commit->object.sha1), NULL);
285         else
286                 argv_array_pushl(&cp.args, "symbolic-ref", "HEAD",
287                                  symref.buf, NULL);
288         cp.env = child_env.argv;
289         ret = run_command(&cp);
290         if (ret)
291                 goto done;
292
293         cp.argv = NULL;
294         argv_array_clear(&cp.args);
295         argv_array_push(&cp.args, "checkout");
296         cp.env = child_env.argv;
297         ret = run_command(&cp);
298         if (!ret) {
299                 is_junk = 0;
300                 free(junk_work_tree);
301                 free(junk_git_dir);
302                 junk_work_tree = NULL;
303                 junk_git_dir = NULL;
304         }
305 done:
306         strbuf_reset(&sb);
307         strbuf_addf(&sb, "%s/locked", sb_repo.buf);
308         unlink_or_warn(sb.buf);
309         argv_array_clear(&child_env);
310         strbuf_release(&sb);
311         strbuf_release(&symref);
312         strbuf_release(&sb_repo);
313         strbuf_release(&sb_git);
314         return ret;
315 }
316
317 static int add(int ac, const char **av, const char *prefix)
318 {
319         struct add_opts opts;
320         const char *new_branch_force = NULL;
321         const char *path, *branch;
322         struct option options[] = {
323                 OPT__FORCE(&opts.force, N_("checkout <branch> even if already checked out in other worktree")),
324                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
325                            N_("create a new branch")),
326                 OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
327                            N_("create or reset a branch")),
328                 OPT_BOOL(0, "detach", &opts.detach, N_("detach HEAD at named commit")),
329                 OPT_END()
330         };
331
332         memset(&opts, 0, sizeof(opts));
333         ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
334         if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
335                 die(_("-b, -B, and --detach are mutually exclusive"));
336         if (ac < 1 || ac > 2)
337                 usage_with_options(worktree_usage, options);
338
339         path = prefix ? prefix_filename(prefix, strlen(prefix), av[0]) : av[0];
340         branch = ac < 2 ? "HEAD" : av[1];
341
342         opts.force_new_branch = !!new_branch_force;
343         if (opts.force_new_branch)
344                 opts.new_branch = new_branch_force;
345
346         if (ac < 2 && !opts.new_branch && !opts.detach) {
347                 int n;
348                 const char *s = worktree_basename(path, &n);
349                 opts.new_branch = xstrndup(s, n);
350         }
351
352         if (opts.new_branch) {
353                 struct child_process cp;
354                 memset(&cp, 0, sizeof(cp));
355                 cp.git_cmd = 1;
356                 argv_array_push(&cp.args, "branch");
357                 if (opts.force_new_branch)
358                         argv_array_push(&cp.args, "--force");
359                 argv_array_push(&cp.args, opts.new_branch);
360                 argv_array_push(&cp.args, branch);
361                 if (run_command(&cp))
362                         return -1;
363                 branch = opts.new_branch;
364         }
365
366         return add_worktree(path, branch, &opts);
367 }
368
369 int cmd_worktree(int ac, const char **av, const char *prefix)
370 {
371         struct option options[] = {
372                 OPT_END()
373         };
374
375         if (ac < 2)
376                 usage_with_options(worktree_usage, options);
377         if (!strcmp(av[1], "add"))
378                 return add(ac - 1, av + 1, prefix);
379         if (!strcmp(av[1], "prune"))
380                 return prune(ac - 1, av + 1, prefix);
381         usage_with_options(worktree_usage, options);
382 }