branch.c

   1 #include "cache.h"
   2 #include "branch.h"
   3 #include "refs.h"
   4 #include "remote.h"
   5 #include "commit.h"
   6 #include "sequencer.h"
   7
   8 struct tracking {
   9         struct refspec spec;
  10         char *src;
  11         const char *remote;
  12         int matches;
  13 };
  14
  15 static int find_tracked_branch(struct remote *remote, void *priv)
  16 {
  17         struct tracking *tracking = priv;
  18
  19         if (!remote_find_tracking(remote, &tracking->spec)) {
  20                 if (++tracking->matches == 1) {
  21                         tracking->src = tracking->spec.src;
  22                         tracking->remote = remote->name;
  23                 } else {
  24                         free(tracking->spec.src);
  25                         if (tracking->src) {
  26                                 free(tracking->src);
  27                                 tracking->src = NULL;
  28                         }
  29                 }
  30                 tracking->spec.src = NULL;
  31         }
  32
  33         return 0;
  34 }
  35
  36 static int should_setup_rebase(const char *origin)
  37 {
  38         switch (autorebase) {
  39         case AUTOREBASE_NEVER:
  40                 return 0;
  41         case AUTOREBASE_LOCAL:
  42                 return origin == NULL;
  43         case AUTOREBASE_REMOTE:
  44                 return origin != NULL;
  45         case AUTOREBASE_ALWAYS:
  46                 return 1;
  47         }
  48         return 0;
  49 }
  50
  51 void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
  52 {
  53         const char *shortname = remote + 11;
  54         int remote_is_branch = !prefixcmp(remote, "refs/heads/");
  55         struct strbuf key = STRBUF_INIT;
  56         int rebasing = should_setup_rebase(origin);
  57
  58         if (remote_is_branch
  59             && !strcmp(local, shortname)
  60             && !origin) {
  61                 warning("Not setting branch %s as its own upstream.",
  62                         local);
  63                 return;
  64         }
  65
  66         strbuf_addf(&key, "branch.%s.remote", local);
  67         git_config_set(key.buf, origin ? origin : ".");
  68
  69         strbuf_reset(&key);
  70         strbuf_addf(&key, "branch.%s.merge", local);
  71         git_config_set(key.buf, remote);
  72
  73         if (rebasing) {
  74                 strbuf_reset(&key);
  75                 strbuf_addf(&key, "branch.%s.rebase", local);
  76                 git_config_set(key.buf, "true");
  77         }
  78
  79         if (flag & BRANCH_CONFIG_VERBOSE) {
  80                 strbuf_reset(&key);
  81
  82                 strbuf_addstr(&key, origin ? "remote" : "local");
  83
  84                 /* Are we tracking a proper "branch"? */
  85                 if (remote_is_branch) {
  86                         strbuf_addf(&key, " branch %s", shortname);
  87                         if (origin)
  88                                 strbuf_addf(&key, " from %s", origin);
  89                 }
  90                 else
  91                         strbuf_addf(&key, " ref %s", remote);
  92                 printf("Branch %s set up to track %s%s.\n",
  93                        local, key.buf,
  94                        rebasing ? " by rebasing" : "");
  95         }
  96         strbuf_release(&key);
  97 }
  98
  99 /*
 100  * This is called when new_ref is branched off of orig_ref, and tries
 101  * to infer the settings for branch.<new_ref>.{remote,merge} from the
 102  * config.
 103  */
 104 static int setup_tracking(const char *new_ref, const char *orig_ref,
 105                           enum branch_track track)
 106 {
 107         struct tracking tracking;
 108
 109         if (strlen(new_ref) > 1024 - 7 - 7 - 1)
 110                 return error("Tracking not set up: name too long: %s",
 111                                 new_ref);
 112
 113         memset(&tracking, 0, sizeof(tracking));
 114         tracking.spec.dst = (char *)orig_ref;
 115         if (for_each_remote(find_tracked_branch, &tracking))
 116                 return 1;
 117
 118         if (!tracking.matches)
 119                 switch (track) {
 120                 case BRANCH_TRACK_ALWAYS:
 121                 case BRANCH_TRACK_EXPLICIT:
 122                 case BRANCH_TRACK_OVERRIDE:
 123                         break;
 124                 default:
 125                         return 1;
 126                 }
 127
 128         if (tracking.matches > 1)
 129                 return error("Not tracking: ambiguous information for ref %s",
 130                                 orig_ref);
 131
 132         install_branch_config(BRANCH_CONFIG_VERBOSE, new_ref, tracking.remote,
 133                               tracking.src ? tracking.src : orig_ref);
 134
 135         free(tracking.src);
 136         return 0;
 137 }
 138
 139 int validate_new_branchname(const char *name, struct strbuf *ref,
 140                             int force, int attr_only)
 141 {
 142         if (strbuf_check_branch_ref(ref, name))
 143                 die("'%s' is not a valid branch name.", name);
 144
 145         if (!ref_exists(ref->buf))
 146                 return 0;
 147         else if (!force && !attr_only)
 148                 die("A branch named '%s' already exists.", ref->buf + strlen("refs/heads/"));
 149
 150         if (!attr_only) {
 151                 const char *head;
 152                 unsigned char sha1[20];
 153
 154                 head = resolve_ref("HEAD", sha1, 0, NULL);
 155                 if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 156                         die("Cannot force update the current branch.");
 157         }
 158         return 1;
 159 }
 160
 161 void create_branch(const char *head,
 162                    const char *name, const char *start_name,
 163                    int force, int reflog, enum branch_track track)
 164 {
 165         struct ref_lock *lock = NULL;
 166         struct commit *commit;
 167         unsigned char sha1[20];
 168         char *real_ref, msg[PATH_MAX + 20];
 169         struct strbuf ref = STRBUF_INIT;
 170         int forcing = 0;
 171         int dont_change_ref = 0;
 172         int explicit_tracking = 0;
 173
 174         if (track == BRANCH_TRACK_EXPLICIT || track == BRANCH_TRACK_OVERRIDE)
 175                 explicit_tracking = 1;
 176
 177         if (validate_new_branchname(name, &ref, force,
 178                                     track == BRANCH_TRACK_OVERRIDE)) {
 179                 if (!force)
 180                         dont_change_ref = 1;
 181                 else
 182                         forcing = 1;
 183         }
 184
 185         real_ref = NULL;
 186         if (get_sha1(start_name, sha1))
 187                 die("Not a valid object name: '%s'.", start_name);
 188
 189         switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
 190         case 0:
 191                 /* Not branching from any existing branch */
 192                 if (explicit_tracking)
 193                         die("Cannot setup tracking information; starting point is not a branch.");
 194                 break;
 195         case 1:
 196                 /* Unique completion -- good, only if it is a real branch */
 197                 if (prefixcmp(real_ref, "refs/heads/") &&
 198                     prefixcmp(real_ref, "refs/remotes/")) {
 199                         if (explicit_tracking)
 200                                 die("Cannot setup tracking information; starting point is not a branch.");
 201                         else
 202                                 real_ref = NULL;
 203                 }
 204                 break;
 205         default:
 206                 die("Ambiguous object name: '%s'.", start_name);
 207                 break;
 208         }
 209
 210         if ((commit = lookup_commit_reference(sha1)) == NULL)
 211                 die("Not a valid branch point: '%s'.", start_name);
 212         hashcpy(sha1, commit->object.sha1);
 213
 214         if (!dont_change_ref) {
 215                 lock = lock_any_ref_for_update(ref.buf, NULL, 0);
 216                 if (!lock)
 217                         die_errno("Failed to lock ref for update");
 218         }
 219
 220         if (reflog)
 221                 log_all_ref_updates = 1;
 222
 223         if (forcing)
 224                 snprintf(msg, sizeof msg, "branch: Reset to %s",
 225                          start_name);
 226         else if (!dont_change_ref)
 227                 snprintf(msg, sizeof msg, "branch: Created from %s",
 228                          start_name);
 229
 230         if (real_ref && track)
 231                 setup_tracking(ref.buf+11, real_ref, track);
 232
 233         if (!dont_change_ref)
 234                 if (write_ref_sha1(lock, sha1, msg) < 0)
 235                         die_errno("Failed to write ref");
 236
 237         strbuf_release(&ref);
 238         free(real_ref);
 239 }
 240
 241 void remove_branch_state(void)
 242 {
 243         unlink(git_path("CHERRY_PICK_HEAD"));
 244         unlink(git_path("MERGE_HEAD"));
 245         unlink(git_path("MERGE_RR"));
 246         unlink(git_path("MERGE_MSG"));
 247         unlink(git_path("MERGE_MODE"));
 248         unlink(git_path("SQUASH_MSG"));
 249         remove_sequencer_state(0);
 250 }