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