Add push --set-upstream
[git] / branch.c
1 #include "cache.h"
2 #include "branch.h"
3 #include "refs.h"
4 #include "remote.h"
5 #include "commit.h"
6
7 struct tracking {
8         struct refspec spec;
9         char *src;
10         const char *remote;
11         int matches;
12 };
13
14 static int find_tracked_branch(struct remote *remote, void *priv)
15 {
16         struct tracking *tracking = priv;
17
18         if (!remote_find_tracking(remote, &tracking->spec)) {
19                 if (++tracking->matches == 1) {
20                         tracking->src = tracking->spec.src;
21                         tracking->remote = remote->name;
22                 } else {
23                         free(tracking->spec.src);
24                         if (tracking->src) {
25                                 free(tracking->src);
26                                 tracking->src = NULL;
27                         }
28                 }
29                 tracking->spec.src = NULL;
30         }
31
32         return 0;
33 }
34
35 static int should_setup_rebase(const char *origin)
36 {
37         switch (autorebase) {
38         case AUTOREBASE_NEVER:
39                 return 0;
40         case AUTOREBASE_LOCAL:
41                 return origin == NULL;
42         case AUTOREBASE_REMOTE:
43                 return origin != NULL;
44         case AUTOREBASE_ALWAYS:
45                 return 1;
46         }
47         return 0;
48 }
49
50 void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
51 {
52         struct strbuf key = STRBUF_INIT;
53         int rebasing = should_setup_rebase(origin);
54
55         strbuf_addf(&key, "branch.%s.remote", local);
56         git_config_set(key.buf, origin ? origin : ".");
57
58         strbuf_reset(&key);
59         strbuf_addf(&key, "branch.%s.merge", local);
60         git_config_set(key.buf, remote);
61
62         if (rebasing) {
63                 strbuf_reset(&key);
64                 strbuf_addf(&key, "branch.%s.rebase", local);
65                 git_config_set(key.buf, "true");
66         }
67
68         if (flag & BRANCH_CONFIG_VERBOSE) {
69                 strbuf_reset(&key);
70
71                 strbuf_addstr(&key, origin ? "remote" : "local");
72
73                 /* Are we tracking a proper "branch"? */
74                 if (!prefixcmp(remote, "refs/heads/")) {
75                         strbuf_addf(&key, " branch %s", remote + 11);
76                         if (origin)
77                                 strbuf_addf(&key, " from %s", origin);
78                 }
79                 else
80                         strbuf_addf(&key, " ref %s", remote);
81                 printf("Branch %s set up to track %s%s.\n",
82                        local, key.buf,
83                        rebasing ? " by rebasing" : "");
84         }
85         strbuf_release(&key);
86 }
87
88 /*
89  * This is called when new_ref is branched off of orig_ref, and tries
90  * to infer the settings for branch.<new_ref>.{remote,merge} from the
91  * config.
92  */
93 static int setup_tracking(const char *new_ref, const char *orig_ref,
94                           enum branch_track track)
95 {
96         struct tracking tracking;
97
98         if (strlen(new_ref) > 1024 - 7 - 7 - 1)
99                 return error("Tracking not set up: name too long: %s",
100                                 new_ref);
101
102         memset(&tracking, 0, sizeof(tracking));
103         tracking.spec.dst = (char *)orig_ref;
104         if (for_each_remote(find_tracked_branch, &tracking))
105                 return 1;
106
107         if (!tracking.matches)
108                 switch (track) {
109                 case BRANCH_TRACK_ALWAYS:
110                 case BRANCH_TRACK_EXPLICIT:
111                         break;
112                 default:
113                         return 1;
114                 }
115
116         if (tracking.matches > 1)
117                 return error("Not tracking: ambiguous information for ref %s",
118                                 orig_ref);
119
120         install_branch_config(BRANCH_CONFIG_VERBOSE, new_ref, tracking.remote,
121                               tracking.src ? tracking.src : orig_ref);
122
123         free(tracking.src);
124         return 0;
125 }
126
127 void create_branch(const char *head,
128                    const char *name, const char *start_name,
129                    int force, int reflog, enum branch_track track)
130 {
131         struct ref_lock *lock;
132         struct commit *commit;
133         unsigned char sha1[20];
134         char *real_ref, msg[PATH_MAX + 20];
135         struct strbuf ref = STRBUF_INIT;
136         int forcing = 0;
137
138         if (strbuf_check_branch_ref(&ref, name))
139                 die("'%s' is not a valid branch name.", name);
140
141         if (resolve_ref(ref.buf, sha1, 1, NULL)) {
142                 if (!force)
143                         die("A branch named '%s' already exists.", name);
144                 else if (!is_bare_repository() && !strcmp(head, name))
145                         die("Cannot force update the current branch.");
146                 forcing = 1;
147         }
148
149         real_ref = NULL;
150         if (get_sha1(start_name, sha1))
151                 die("Not a valid object name: '%s'.", start_name);
152
153         switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
154         case 0:
155                 /* Not branching from any existing branch */
156                 if (track == BRANCH_TRACK_EXPLICIT)
157                         die("Cannot setup tracking information; starting point is not a branch.");
158                 break;
159         case 1:
160                 /* Unique completion -- good, only if it is a real ref */
161                 if (track == BRANCH_TRACK_EXPLICIT && !strcmp(real_ref, "HEAD"))
162                         die("Cannot setup tracking information; starting point is not a branch.");
163                 break;
164         default:
165                 die("Ambiguous object name: '%s'.", start_name);
166                 break;
167         }
168
169         if ((commit = lookup_commit_reference(sha1)) == NULL)
170                 die("Not a valid branch point: '%s'.", start_name);
171         hashcpy(sha1, commit->object.sha1);
172
173         lock = lock_any_ref_for_update(ref.buf, NULL, 0);
174         if (!lock)
175                 die_errno("Failed to lock ref for update");
176
177         if (reflog)
178                 log_all_ref_updates = 1;
179
180         if (forcing)
181                 snprintf(msg, sizeof msg, "branch: Reset from %s",
182                          start_name);
183         else
184                 snprintf(msg, sizeof msg, "branch: Created from %s",
185                          start_name);
186
187         if (real_ref && track)
188                 setup_tracking(name, real_ref, track);
189
190         if (write_ref_sha1(lock, sha1, msg) < 0)
191                 die_errno("Failed to write ref");
192
193         strbuf_release(&ref);
194         free(real_ref);
195 }
196
197 void remove_branch_state(void)
198 {
199         unlink(git_path("MERGE_HEAD"));
200         unlink(git_path("MERGE_RR"));
201         unlink(git_path("MERGE_MSG"));
202         unlink(git_path("MERGE_MODE"));
203         unlink(git_path("SQUASH_MSG"));
204 }