Merge branch 'jc/detached-head-doc' into maint
[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
97         hex = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
98         printf(_("HEAD is now at %s"), hex);
99         body = strstr(commit->buffer, "\n\n");
100         if (body) {
101                 const char *eol;
102                 size_t len;
103                 body += 2;
104                 eol = strchr(body, '\n');
105                 len = eol ? eol - body : strlen(body);
106                 printf(" %.*s\n", (int) len, body);
107         }
108         else
109                 printf("\n");
110 }
111
112 static void update_index_from_diff(struct diff_queue_struct *q,
113                 struct diff_options *opt, void *data)
114 {
115         int i;
116
117         for (i = 0; i < q->nr; i++) {
118                 struct diff_filespec *one = q->queue[i]->one;
119                 if (one->mode && !is_null_sha1(one->sha1)) {
120                         struct cache_entry *ce;
121                         ce = make_cache_entry(one->mode, one->sha1, one->path,
122                                 0, 0);
123                         if (!ce)
124                                 die(_("make_cache_entry failed for path '%s'"),
125                                     one->path);
126                         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
127                                 ADD_CACHE_OK_TO_REPLACE);
128                 } else
129                         remove_file_from_cache(one->path);
130         }
131 }
132
133 static int read_from_tree(const char **pathspec, unsigned char *tree_sha1)
134 {
135         struct diff_options opt;
136
137         memset(&opt, 0, sizeof(opt));
138         diff_tree_setup_paths(pathspec, &opt);
139         opt.output_format = DIFF_FORMAT_CALLBACK;
140         opt.format_callback = update_index_from_diff;
141
142         read_cache();
143         if (do_diff_cache(tree_sha1, &opt))
144                 return 1;
145         diffcore_std(&opt);
146         diff_flush(&opt);
147         diff_tree_release_paths(&opt);
148
149         return 0;
150 }
151
152 static void set_reflog_message(struct strbuf *sb, const char *action,
153                                const char *rev)
154 {
155         const char *rla = getenv("GIT_REFLOG_ACTION");
156
157         strbuf_reset(sb);
158         if (rla)
159                 strbuf_addf(sb, "%s: %s", rla, action);
160         else if (rev)
161                 strbuf_addf(sb, "reset: moving to %s", rev);
162         else
163                 strbuf_addf(sb, "reset: %s", action);
164 }
165
166 static void die_if_unmerged_cache(int reset_type)
167 {
168         if (is_merge() || read_cache() < 0 || unmerged_cache())
169                 die(_("Cannot do a %s reset in the middle of a merge."),
170                     _(reset_type_names[reset_type]));
171
172 }
173
174 static const char **parse_args(const char **argv, const char *prefix, const char **rev_ret)
175 {
176         const char *rev = "HEAD";
177         unsigned char unused[20];
178         /*
179          * Possible arguments are:
180          *
181          * git reset [-opts] [<rev>]
182          * git reset [-opts] <tree> [<paths>...]
183          * git reset [-opts] <tree> -- [<paths>...]
184          * git reset [-opts] -- [<paths>...]
185          * git reset [-opts] <paths>...
186          *
187          * At this point, argv points immediately after [-opts].
188          */
189
190         if (argv[0]) {
191                 if (!strcmp(argv[0], "--")) {
192                         argv++; /* reset to HEAD, possibly with paths */
193                 } else if (argv[1] && !strcmp(argv[1], "--")) {
194                         rev = argv[0];
195                         argv += 2;
196                 }
197                 /*
198                  * Otherwise, argv[0] could be either <rev> or <paths> and
199                  * has to be unambiguous. If there is a single argument, it
200                  * can not be a tree
201                  */
202                 else if ((!argv[1] && !get_sha1_committish(argv[0], unused)) ||
203                          (argv[1] && !get_sha1_treeish(argv[0], unused))) {
204                         /*
205                          * Ok, argv[0] looks like a commit/tree; it should not
206                          * be a filename.
207                          */
208                         verify_non_filename(prefix, argv[0]);
209                         rev = *argv++;
210                 } else {
211                         /* Otherwise we treat this as a filename */
212                         verify_filename(prefix, argv[0], 1);
213                 }
214         }
215         *rev_ret = rev;
216         return argv[0] ? get_pathspec(prefix, argv) : NULL;
217 }
218
219 static int update_refs(const char *rev, const unsigned char *sha1)
220 {
221         int update_ref_status;
222         struct strbuf msg = STRBUF_INIT;
223         unsigned char *orig = NULL, sha1_orig[20],
224                 *old_orig = NULL, sha1_old_orig[20];
225
226         if (!get_sha1("ORIG_HEAD", sha1_old_orig))
227                 old_orig = sha1_old_orig;
228         if (!get_sha1("HEAD", sha1_orig)) {
229                 orig = sha1_orig;
230                 set_reflog_message(&msg, "updating ORIG_HEAD", NULL);
231                 update_ref(msg.buf, "ORIG_HEAD", orig, old_orig, 0, MSG_ON_ERR);
232         } else if (old_orig)
233                 delete_ref("ORIG_HEAD", old_orig, 0);
234         set_reflog_message(&msg, "updating HEAD", rev);
235         update_ref_status = update_ref(msg.buf, "HEAD", sha1, orig, 0, MSG_ON_ERR);
236         strbuf_release(&msg);
237         return update_ref_status;
238 }
239
240 int cmd_reset(int argc, const char **argv, const char *prefix)
241 {
242         int reset_type = NONE, update_ref_status = 0, quiet = 0;
243         int patch_mode = 0, unborn;
244         const char *rev;
245         unsigned char sha1[20];
246         const char **pathspec = NULL;
247         const struct option options[] = {
248                 OPT__QUIET(&quiet, N_("be quiet, only report errors")),
249                 OPT_SET_INT(0, "mixed", &reset_type,
250                                                 N_("reset HEAD and index"), MIXED),
251                 OPT_SET_INT(0, "soft", &reset_type, N_("reset only HEAD"), SOFT),
252                 OPT_SET_INT(0, "hard", &reset_type,
253                                 N_("reset HEAD, index and working tree"), HARD),
254                 OPT_SET_INT(0, "merge", &reset_type,
255                                 N_("reset HEAD, index and working tree"), MERGE),
256                 OPT_SET_INT(0, "keep", &reset_type,
257                                 N_("reset HEAD but keep local changes"), KEEP),
258                 OPT_BOOLEAN('p', "patch", &patch_mode, N_("select hunks interactively")),
259                 OPT_END()
260         };
261
262         git_config(git_default_config, NULL);
263
264         argc = parse_options(argc, argv, prefix, options, git_reset_usage,
265                                                 PARSE_OPT_KEEP_DASHDASH);
266         pathspec = parse_args(argv, prefix, &rev);
267
268         unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", sha1);
269         if (unborn) {
270                 /* reset on unborn branch: treat as reset to empty tree */
271                 hashcpy(sha1, EMPTY_TREE_SHA1_BIN);
272         } else if (!pathspec) {
273                 struct commit *commit;
274                 if (get_sha1_committish(rev, sha1))
275                         die(_("Failed to resolve '%s' as a valid revision."), rev);
276                 commit = lookup_commit_reference(sha1);
277                 if (!commit)
278                         die(_("Could not parse object '%s'."), rev);
279                 hashcpy(sha1, commit->object.sha1);
280         } else {
281                 struct tree *tree;
282                 if (get_sha1_treeish(rev, sha1))
283                         die(_("Failed to resolve '%s' as a valid tree."), rev);
284                 tree = parse_tree_indirect(sha1);
285                 if (!tree)
286                         die(_("Could not parse object '%s'."), rev);
287                 hashcpy(sha1, tree->object.sha1);
288         }
289
290         if (patch_mode) {
291                 if (reset_type != NONE)
292                         die(_("--patch is incompatible with --{hard,mixed,soft}"));
293                 return run_add_interactive(sha1_to_hex(sha1), "--patch=reset", pathspec);
294         }
295
296         /* git reset tree [--] paths... can be used to
297          * load chosen paths from the tree into the index without
298          * affecting the working tree nor HEAD. */
299         if (pathspec) {
300                 if (reset_type == MIXED)
301                         warning(_("--mixed with paths is deprecated; use 'git reset -- <paths>' instead."));
302                 else if (reset_type != NONE)
303                         die(_("Cannot do %s reset with paths."),
304                                         _(reset_type_names[reset_type]));
305         }
306         if (reset_type == NONE)
307                 reset_type = MIXED; /* by default */
308
309         if (reset_type != SOFT && reset_type != MIXED)
310                 setup_work_tree();
311
312         if (reset_type == MIXED && is_bare_repository())
313                 die(_("%s reset is not allowed in a bare repository"),
314                     _(reset_type_names[reset_type]));
315
316         /* Soft reset does not touch the index file nor the working tree
317          * at all, but requires them in a good order.  Other resets reset
318          * the index file to the tree object we are switching to. */
319         if (reset_type == SOFT || reset_type == KEEP)
320                 die_if_unmerged_cache(reset_type);
321
322         if (reset_type != SOFT) {
323                 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
324                 int newfd = hold_locked_index(lock, 1);
325                 if (reset_type == MIXED) {
326                         if (read_from_tree(pathspec, sha1))
327                                 return 1;
328                 } else {
329                         int err = reset_index(sha1, reset_type, quiet);
330                         if (reset_type == KEEP && !err)
331                                 err = reset_index(sha1, MIXED, quiet);
332                         if (err)
333                                 die(_("Could not reset index file to revision '%s'."), rev);
334                 }
335
336                 if (reset_type == MIXED) { /* Report what has not been updated. */
337                         int flags = quiet ? REFRESH_QUIET : REFRESH_IN_PORCELAIN;
338                         refresh_index(&the_index, flags, NULL, NULL,
339                                       _("Unstaged changes after reset:"));
340                 }
341
342                 if (write_cache(newfd, active_cache, active_nr) ||
343                     commit_locked_index(lock))
344                         die(_("Could not write new index file."));
345         }
346
347         if (!pathspec && !unborn) {
348                 /* Any resets without paths update HEAD to the head being
349                  * switched to, saving the previous head in ORIG_HEAD before. */
350                 update_ref_status = update_refs(rev, sha1);
351
352                 if (reset_type == HARD && !update_ref_status && !quiet)
353                         print_new_head_line(lookup_commit_reference(sha1));
354         }
355         if (!pathspec)
356                 remove_branch_state();
357
358         return update_ref_status;
359 }