Merge branch 'so/rebase-doc-fork-point'
[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(&the_index, 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         const 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         unuse_commit_buffer(commit, msg);
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         int intent_to_add = *(int *)data;
120
121         for (i = 0; i < q->nr; i++) {
122                 struct diff_filespec *one = q->queue[i]->one;
123                 int is_missing = !(one->mode && !is_null_sha1(one->sha1));
124                 struct cache_entry *ce;
125
126                 if (is_missing && !intent_to_add) {
127                         remove_file_from_cache(one->path);
128                         continue;
129                 }
130
131                 ce = make_cache_entry(one->mode, one->sha1, one->path,
132                                       0, 0);
133                 if (!ce)
134                         die(_("make_cache_entry failed for path '%s'"),
135                             one->path);
136                 if (is_missing) {
137                         ce->ce_flags |= CE_INTENT_TO_ADD;
138                         set_object_name_for_intent_to_add_entry(ce);
139                 }
140                 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
141         }
142 }
143
144 static int read_from_tree(const struct pathspec *pathspec,
145                           unsigned char *tree_sha1,
146                           int intent_to_add)
147 {
148         struct diff_options opt;
149
150         memset(&opt, 0, sizeof(opt));
151         copy_pathspec(&opt.pathspec, pathspec);
152         opt.output_format = DIFF_FORMAT_CALLBACK;
153         opt.format_callback = update_index_from_diff;
154         opt.format_callback_data = &intent_to_add;
155
156         if (do_diff_cache(tree_sha1, &opt))
157                 return 1;
158         diffcore_std(&opt);
159         diff_flush(&opt);
160         free_pathspec(&opt.pathspec);
161
162         return 0;
163 }
164
165 static void set_reflog_message(struct strbuf *sb, const char *action,
166                                const char *rev)
167 {
168         const char *rla = getenv("GIT_REFLOG_ACTION");
169
170         strbuf_reset(sb);
171         if (rla)
172                 strbuf_addf(sb, "%s: %s", rla, action);
173         else if (rev)
174                 strbuf_addf(sb, "reset: moving to %s", rev);
175         else
176                 strbuf_addf(sb, "reset: %s", action);
177 }
178
179 static void die_if_unmerged_cache(int reset_type)
180 {
181         if (is_merge() || unmerged_cache())
182                 die(_("Cannot do a %s reset in the middle of a merge."),
183                     _(reset_type_names[reset_type]));
184
185 }
186
187 static void parse_args(struct pathspec *pathspec,
188                        const char **argv, const char *prefix,
189                        int patch_mode,
190                        const char **rev_ret)
191 {
192         const char *rev = "HEAD";
193         unsigned char unused[20];
194         /*
195          * Possible arguments are:
196          *
197          * git reset [-opts] [<rev>]
198          * git reset [-opts] <tree> [<paths>...]
199          * git reset [-opts] <tree> -- [<paths>...]
200          * git reset [-opts] -- [<paths>...]
201          * git reset [-opts] <paths>...
202          *
203          * At this point, argv points immediately after [-opts].
204          */
205
206         if (argv[0]) {
207                 if (!strcmp(argv[0], "--")) {
208                         argv++; /* reset to HEAD, possibly with paths */
209                 } else if (argv[1] && !strcmp(argv[1], "--")) {
210                         rev = argv[0];
211                         argv += 2;
212                 }
213                 /*
214                  * Otherwise, argv[0] could be either <rev> or <paths> and
215                  * has to be unambiguous. If there is a single argument, it
216                  * can not be a tree
217                  */
218                 else if ((!argv[1] && !get_sha1_committish(argv[0], unused)) ||
219                          (argv[1] && !get_sha1_treeish(argv[0], unused))) {
220                         /*
221                          * Ok, argv[0] looks like a commit/tree; it should not
222                          * be a filename.
223                          */
224                         verify_non_filename(prefix, argv[0]);
225                         rev = *argv++;
226                 } else {
227                         /* Otherwise we treat this as a filename */
228                         verify_filename(prefix, argv[0], 1);
229                 }
230         }
231         *rev_ret = rev;
232
233         if (read_cache() < 0)
234                 die(_("index file corrupt"));
235
236         parse_pathspec(pathspec, 0,
237                        PATHSPEC_PREFER_FULL |
238                        PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP |
239                        (patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0),
240                        prefix, argv);
241 }
242
243 static int reset_refs(const char *rev, const unsigned char *sha1)
244 {
245         int update_ref_status;
246         struct strbuf msg = STRBUF_INIT;
247         unsigned char *orig = NULL, sha1_orig[20],
248                 *old_orig = NULL, sha1_old_orig[20];
249
250         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
251                 old_orig = sha1_old_orig;
252         if (!get_sha1("HEAD", sha1_orig)) {
253                 orig = sha1_orig;
254                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
255                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0,
256                            UPDATE_REFS_MSG_ON_ERR);
257         } else if (old_orig)
258                 delete_ref("ORIG_HEAD", old_orig, 0);
259         set_reflog_message(&msg, "updating HEAD", rev);
260         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0,
261                                        UPDATE_REFS_MSG_ON_ERR);
262         strbuf_release(&msg);
263         return update_ref_status;
264 }
265
266 int cmd_reset(int argc, const char **argv, const char *prefix)
267 {
268         int reset_type = NONE, update_ref_status = 0, quiet = 0;
269         int patch_mode = 0, unborn;
270         const char *rev;
271         unsigned char sha1[20];
272         struct pathspec pathspec;
273         int intent_to_add = 0;
274         const struct option options[] = {
275                 OPT__QUIET(&quiet, N_("be quiet, only report errors")),
276                 OPT_SET_INT(0, "mixed", &reset_type,
277                                                 N_("reset HEAD and index"), MIXED),
278                 OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
279                 OPT_SET_INT(0, "hard", &reset_type,
280                                 N_("reset HEAD, index and working tree"), HARD),
281                 OPT_SET_INT(0, "merge", &reset_type,
282                                 N_("reset HEAD, index and working tree"), MERGE),
283                 OPT_SET_INT(0, "keep", &reset_type,
284                                 N_("reset HEAD but keep local changes"), KEEP),
285                 OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),
286                 OPT_BOOL('N', "intent-to-add", &intent_to_add,
287                                 N_("record only the fact that removed paths will be added later")),
288                 OPT_END()
289         };
290
291         git_config(git_default_config, NULL);
292
293         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
294                                                 PARSE_OPT_KEEP_DASHDASH);
295         parse_args(&pathspec, argv, prefix, patch_mode, &rev);
296
297         unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", sha1);
298         if (unborn) {
299                 /* reset on unborn branch: treat as reset to empty tree */
300                 hashcpy(sha1, EMPTY_TREE_SHA1_BIN);
301         } else if (!pathspec.nr) {
302                 struct commit *commit;
303                 if (get_sha1_committish(rev, sha1))
304                         die(_("Failed to resolve '%s' as a valid revision."), rev);
305                 commit = lookup_commit_reference(sha1);
306                 if (!commit)
307                         die(_("Could not parse object '%s'."), rev);
308                 hashcpy(sha1, commit->object.sha1);
309         } else {
310                 struct tree *tree;
311                 if (get_sha1_treeish(rev, sha1))
312                         die(_("Failed to resolve '%s' as a valid tree."), rev);
313                 tree = parse_tree_indirect(sha1);
314                 if (!tree)
315                         die(_("Could not parse object '%s'."), rev);
316                 hashcpy(sha1, tree->object.sha1);
317         }
318
319         if (patch_mode) {
320                 if (reset_type != NONE)
321                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
322                 return run_add_interactive(rev, "--patch=reset", &pathspec);
323         }
324
325         /* git reset tree [--] paths... can be used to
326          * load chosen paths from the tree into the index without
327          * affecting the working tree nor HEAD. */
328         if (pathspec.nr) {
329                 if (reset_type == MIXED)
330                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
331                 else if (reset_type != NONE)
332                         die(_("Cannot do %s reset with paths."),
333                                         _(reset_type_names[reset_type]));
334         }
335         if (reset_type == NONE)
336                 reset_type = MIXED; /* by default */
337
338         if (reset_type != SOFT && (reset_type != MIXED || get_git_work_tree()))
339                 setup_work_tree();
340
341         if (reset_type == MIXED && is_bare_repository())
342                 die(_("%s reset is not allowed in a bare repository"),
343                     _(reset_type_names[reset_type]));
344
345         if (intent_to_add && reset_type != MIXED)
346                 die(_("-N can only be used with --mixed"));
347
348         /* Soft reset does not touch the index file nor the working tree
349          * at all, but requires them in a good order.  Other resets reset
350          * the index file to the tree object we are switching to. */
351         if (reset_type == SOFT || reset_type == KEEP)
352                 die_if_unmerged_cache(reset_type);
353
354         if (reset_type != SOFT) {
355                 struct lock_file *lock = xcalloc(1, sizeof(*lock));
356                 hold_locked_index(lock, 1);
357                 if (reset_type == MIXED) {
358                         int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
359                         if (read_from_tree(&pathspec, sha1, intent_to_add))
360                                 return 1;
361                         if (get_git_work_tree())
362                                 refresh_index(&the_index, flags, NULL, NULL,
363                                               _("Unstaged changes after reset:"));
364                 } else {
365                         int err = reset_index(sha1, reset_type, quiet);
366                         if (reset_type == KEEP && !err)
367                                 err = reset_index(sha1, MIXED, quiet);
368                         if (err)
369                                 die(_("Could not reset index file to revision '%s'."), rev);
370                 }
371
372                 if (write_locked_index(&the_index, lock, COMMIT_LOCK))
373                         die(_("Could not write new index file."));
374         }
375
376         if (!pathspec.nr && !unborn) {
377                 /* Any resets without paths update HEAD to the head being
378                  * switched to, saving the previous head in ORIG_HEAD before. */
379                 update_ref_status = reset_refs(rev, sha1);
380
381                 if (reset_type == HARD && !update_ref_status && !quiet)
382                         print_new_head_line(lookup_commit_reference(sha1));
383         }
384         if (!pathspec.nr)
385                 remove_branch_state();
386
387         return update_ref_status;
388 }