update-ref: fail create operation over stdin if ref already exists
[git] / builtin / reset.c
1 /*
2  * "git reset" builtin command
3  *
4  * Copyright (c) 2007 Carlos Rica
5  *
6  * Based on git-reset.sh, which is
7  *
8  * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano
9  */
10 #include "builtin.h"
11 #include "tag.h"
12 #include "object.h"
13 #include "commit.h"
14 #include "run-command.h"
15 #include "refs.h"
16 #include "diff.h"
17 #include "diffcore.h"
18 #include "tree.h"
19 #include "branch.h"
20 #include "parse-options.h"
21 #include "unpack-trees.h"
22 #include "cache-tree.h"
23
24 static const char * const git_reset_usage[] = {
25         N_("git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]"),
26         N_("git reset [-q] <tree-ish> [--] <paths>..."),
27         N_("git reset --patch [<tree-ish>] [--] [<paths>...]"),
28         NULL
29 };
30
31 enum reset_type { MIXED, SOFT, HARD, MERGE, KEEP, NONE };
32 static const char *reset_type_names[] = {
33         N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL
34 };
35
36 static inline int is_merge(void)
37 {
38         return !access(git_path("MERGE_HEAD"), F_OK);
39 }
40
41 static int reset_index(const unsigned char *sha1, int reset_type, int quiet)
42 {
43         int nr = 1;
44         struct tree_desc desc[2];
45         struct tree *tree;
46         struct unpack_trees_options opts;
47
48         memset(&opts, 0, sizeof(opts));
49         opts.head_idx = 1;
50         opts.src_index = &the_index;
51         opts.dst_index = &the_index;
52         opts.fn = oneway_merge;
53         opts.merge = 1;
54         if (!quiet)
55                 opts.verbose_update = 1;
56         switch (reset_type) {
57         case KEEP:
58         case MERGE:
59                 opts.update = 1;
60                 break;
61         case HARD:
62                 opts.update = 1;
63                 /* fallthrough */
64         default:
65                 opts.reset = 1;
66         }
67
68         read_cache_unmerged();
69
70         if (reset_type == KEEP) {
71                 unsigned char head_sha1[20];
72                 if (get_sha1("HEAD", head_sha1))
73                         return error(_("You do not have a valid HEAD."));
74                 if (!fill_tree_descriptor(desc, head_sha1))
75                         return error(_("Failed to find tree of HEAD."));
76                 nr++;
77                 opts.fn = twoway_merge;
78         }
79
80         if (!fill_tree_descriptor(desc + nr - 1, sha1))
81                 return error(_("Failed to find tree of %s."), sha1_to_hex(sha1));
82         if (unpack_trees(nr, desc, &opts))
83                 return -1;
84
85         if (reset_type == MIXED || reset_type == HARD) {
86                 tree = parse_tree_indirect(sha1);
87                 prime_cache_tree(&active_cache_tree, tree);
88         }
89
90         return 0;
91 }
92
93 static void print_new_head_line(struct commit *commit)
94 {
95         const char *hex, *body;
96         char *msg;
97
98         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
99         printf(_("HEAD is now at %s"), hex);
100         msg = logmsg_reencode(commit, NULL, get_log_output_encoding());
101         body = strstr(msg, "\n\n");
102         if (body) {
103                 const char *eol;
104                 size_t len;
105                 body += 2;
106                 eol = strchr(body, '\n');
107                 len = eol ? eol - body : strlen(body);
108                 printf(" %.*s\n", (int) len, body);
109         }
110         else
111                 printf("\n");
112         logmsg_free(msg, commit);
113 }
114
115 static void update_index_from_diff(struct diff_queue_struct *q,
116                 struct diff_options *opt, void *data)
117 {
118         int i;
119
120         for (i = 0; i < q->nr; i++) {
121                 struct diff_filespec *one = q->queue[i]->one;
122                 if (one->mode && !is_null_sha1(one->sha1)) {
123                         struct cache_entry *ce;
124                         ce = make_cache_entry(one->mode, one->sha1, one->path,
125                                 0, 0);
126                         if (!ce)
127                                 die(_("make_cache_entry failed for path '%s'"),
128                                     one->path);
129                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
130                                 ADD_CACHE_OK_TO_REPLACE);
131                 } else
132                         remove_file_from_cache(one->path);
133         }
134 }
135
136 static int read_from_tree(const struct pathspec *pathspec,
137                           unsigned char *tree_sha1)
138 {
139         struct diff_options opt;
140
141         memset(&opt, 0, sizeof(opt));
142         copy_pathspec(&opt.pathspec, pathspec);
143         opt.output_format = DIFF_FORMAT_CALLBACK;
144         opt.format_callback = update_index_from_diff;
145
146         if (do_diff_cache(tree_sha1, &opt))
147                 return 1;
148         diffcore_std(&opt);
149         diff_flush(&opt);
150         free_pathspec(&opt.pathspec);
151
152         return 0;
153 }
154
155 static void set_reflog_message(struct strbuf *sb, const char *action,
156                                const char *rev)
157 {
158         const char *rla = getenv("GIT_REFLOG_ACTION");
159
160         strbuf_reset(sb);
161         if (rla)
162                 strbuf_addf(sb, "%s: %s", rla, action);
163         else if (rev)
164                 strbuf_addf(sb, "reset: moving to %s", rev);
165         else
166                 strbuf_addf(sb, "reset: %s", action);
167 }
168
169 static void die_if_unmerged_cache(int reset_type)
170 {
171         if (is_merge() || unmerged_cache())
172                 die(_("Cannot do a %s reset in the middle of a merge."),
173                     _(reset_type_names[reset_type]));
174
175 }
176
177 static void parse_args(struct pathspec *pathspec,
178                        const char **argv, const char *prefix,
179                        int patch_mode,
180                        const char **rev_ret)
181 {
182         const char *rev = "HEAD";
183         unsigned char unused[20];
184         /*
185          * Possible arguments are:
186          *
187          * git reset [-opts] [<rev>]
188          * git reset [-opts] <tree> [<paths>...]
189          * git reset [-opts] <tree> -- [<paths>...]
190          * git reset [-opts] -- [<paths>...]
191          * git reset [-opts] <paths>...
192          *
193          * At this point, argv points immediately after [-opts].
194          */
195
196         if (argv[0]) {
197                 if (!strcmp(argv[0], "--")) {
198                         argv++; /* reset to HEAD, possibly with paths */
199                 } else if (argv[1] && !strcmp(argv[1], "--")) {
200                         rev = argv[0];
201                         argv += 2;
202                 }
203                 /*
204                  * Otherwise, argv[0] could be either <rev> or <paths> and
205                  * has to be unambiguous. If there is a single argument, it
206                  * can not be a tree
207                  */
208                 else if ((!argv[1] && !get_sha1_committish(argv[0], unused)) ||
209                          (argv[1] && !get_sha1_treeish(argv[0], unused))) {
210                         /*
211                          * Ok, argv[0] looks like a commit/tree; it should not
212                          * be a filename.
213                          */
214                         verify_non_filename(prefix, argv[0]);
215                         rev = *argv++;
216                 } else {
217                         /* Otherwise we treat this as a filename */
218                         verify_filename(prefix, argv[0], 1);
219                 }
220         }
221         *rev_ret = rev;
222
223         if (read_cache() < 0)
224                 die(_("index file corrupt"));
225
226         parse_pathspec(pathspec, 0,
227                        PATHSPEC_PREFER_FULL |
228                        PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP |
229                        (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
230                        prefix, argv);
231 }
232
233 static int reset_refs(const char *rev, const unsigned char *sha1)
234 {
235         int update_ref_status;
236         struct strbuf msg = STRBUF_INIT;
237         unsigned char *orig = NULL, sha1_orig[20],
238                 *old_orig = NULL, sha1_old_orig[20];
239
240         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
241                 old_orig = sha1_old_orig;
242         if (!get_sha1("HEAD", sha1_orig)) {
243                 orig = sha1_orig;
244                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
245                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
246         } else if (old_orig)
247                 delete_ref("ORIG_HEAD", old_orig, 0);
248         set_reflog_message(&msg, "updating HEAD", rev);
249         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
250         strbuf_release(&msg);
251         return update_ref_status;
252 }
253
254 int cmd_reset(int argc, const char **argv, const char *prefix)
255 {
256         int reset_type = NONE, update_ref_status = 0, quiet = 0;
257         int patch_mode = 0, unborn;
258         const char *rev;
259         unsigned char sha1[20];
260         struct pathspec pathspec;
261         const struct option options[] = {
262                 OPT__QUIET(&quiet, N_("be quiet, only report errors")),
263                 OPT_SET_INT(0, "mixed", &reset_type,
264                                                 N_("reset HEAD and index"), MIXED),
265                 OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
266                 OPT_SET_INT(0, "hard", &reset_type,
267                                 N_("reset HEAD, index and working tree"), HARD),
268                 OPT_SET_INT(0, "merge", &reset_type,
269                                 N_("reset HEAD, index and working tree"), MERGE),
270                 OPT_SET_INT(0, "keep", &reset_type,
271                                 N_("reset HEAD but keep local changes"), KEEP),
272                 OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),
273                 OPT_END()
274         };
275
276         git_config(git_default_config, NULL);
277
278         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
279                                                 PARSE_OPT_KEEP_DASHDASH);
280         parse_args(&pathspec, argv, prefix, patch_mode, &rev);
281
282         unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", sha1);
283         if (unborn) {
284                 /* reset on unborn branch: treat as reset to empty tree */
285                 hashcpy(sha1, EMPTY_TREE_SHA1_BIN);
286         } else if (!pathspec.nr) {
287                 struct commit *commit;
288                 if (get_sha1_committish(rev, sha1))
289                         die(_("Failed to resolve '%s' as a valid revision."), rev);
290                 commit = lookup_commit_reference(sha1);
291                 if (!commit)
292                         die(_("Could not parse object '%s'."), rev);
293                 hashcpy(sha1, commit->object.sha1);
294         } else {
295                 struct tree *tree;
296                 if (get_sha1_treeish(rev, sha1))
297                         die(_("Failed to resolve '%s' as a valid tree."), rev);
298                 tree = parse_tree_indirect(sha1);
299                 if (!tree)
300                         die(_("Could not parse object '%s'."), rev);
301                 hashcpy(sha1, tree->object.sha1);
302         }
303
304         if (patch_mode) {
305                 if (reset_type != NONE)
306                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
307                 return run_add_interactive(rev, "--patch=reset", &pathspec);
308         }
309
310         /* git reset tree [--] paths... can be used to
311          * load chosen paths from the tree into the index without
312          * affecting the working tree nor HEAD. */
313         if (pathspec.nr) {
314                 if (reset_type == MIXED)
315                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
316                 else if (reset_type != NONE)
317                         die(_("Cannot do %s reset with paths."),
318                                         _(reset_type_names[reset_type]));
319         }
320         if (reset_type == NONE)
321                 reset_type = MIXED; /* by default */
322
323         if (reset_type != SOFT && reset_type != MIXED)
324                 setup_work_tree();
325
326         if (reset_type == MIXED && is_bare_repository())
327                 die(_("%s reset is not allowed in a bare repository"),
328                     _(reset_type_names[reset_type]));
329
330         /* Soft reset does not touch the index file nor the working tree
331          * at all, but requires them in a good order.  Other resets reset
332          * the index file to the tree object we are switching to. */
333         if (reset_type == SOFT || reset_type == KEEP)
334                 die_if_unmerged_cache(reset_type);
335
336         if (reset_type != SOFT) {
337                 struct lock_file *lock = xcalloc(1, sizeof(*lock));
338                 int newfd = hold_locked_index(lock, 1);
339                 if (reset_type == MIXED) {
340                         int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
341                         if (read_from_tree(&pathspec, sha1))
342                                 return 1;
343                         refresh_index(&the_index, flags, NULL, NULL,
344                                       _("Unstaged changes after reset:"));
345                 } else {
346                         int err = reset_index(sha1, reset_type, quiet);
347                         if (reset_type == KEEP && !err)
348                                 err = reset_index(sha1, MIXED, quiet);
349                         if (err)
350                                 die(_("Could not reset index file to revision '%s'."), rev);
351                 }
352
353                 if (write_cache(newfd, active_cache, active_nr) ||
354                     commit_locked_index(lock))
355                         die(_("Could not write new index file."));
356         }
357
358         if (!pathspec.nr && !unborn) {
359                 /* Any resets without paths update HEAD to the head being
360                  * switched to, saving the previous head in ORIG_HEAD before. */
361                 update_ref_status = reset_refs(rev, sha1);
362
363                 if (reset_type == HARD && !update_ref_status && !quiet)
364                         print_new_head_line(lookup_commit_reference(sha1));
365         }
366         if (!pathspec.nr)
367                 remove_branch_state();
368
369         return update_ref_status;
370 }