notes-merge.con commit Merge branch 'nd/command-list' (2289880)
   1#include "cache.h"
   2#include "commit.h"
   3#include "refs.h"
   4#include "diff.h"
   5#include "diffcore.h"
   6#include "xdiff-interface.h"
   7#include "ll-merge.h"
   8#include "dir.h"
   9#include "notes.h"
  10#include "notes-merge.h"
  11#include "strbuf.h"
  12#include "notes-utils.h"
  13
  14struct notes_merge_pair {
  15        struct object_id obj, base, local, remote;
  16};
  17
  18void init_notes_merge_options(struct notes_merge_options *o)
  19{
  20        memset(o, 0, sizeof(struct notes_merge_options));
  21        strbuf_init(&(o->commit_msg), 0);
  22        o->verbosity = NOTES_MERGE_VERBOSITY_DEFAULT;
  23}
  24
  25static int path_to_oid(const char *path, struct object_id *oid)
  26{
  27        char hex_oid[GIT_SHA1_HEXSZ];
  28        int i = 0;
  29        while (*path && i < GIT_SHA1_HEXSZ) {
  30                if (*path != '/')
  31                        hex_oid[i++] = *path;
  32                path++;
  33        }
  34        if (*path || i != GIT_SHA1_HEXSZ)
  35                return -1;
  36        return get_oid_hex(hex_oid, oid);
  37}
  38
  39static int verify_notes_filepair(struct diff_filepair *p, struct object_id *oid)
  40{
  41        switch (p->status) {
  42        case DIFF_STATUS_MODIFIED:
  43                assert(p->one->mode == p->two->mode);
  44                assert(!is_null_oid(&p->one->oid));
  45                assert(!is_null_oid(&p->two->oid));
  46                break;
  47        case DIFF_STATUS_ADDED:
  48                assert(is_null_oid(&p->one->oid));
  49                break;
  50        case DIFF_STATUS_DELETED:
  51                assert(is_null_oid(&p->two->oid));
  52                break;
  53        default:
  54                return -1;
  55        }
  56        assert(!strcmp(p->one->path, p->two->path));
  57        return path_to_oid(p->one->path, oid);
  58}
  59
  60static struct notes_merge_pair *find_notes_merge_pair_pos(
  61                struct notes_merge_pair *list, int len, struct object_id *obj,
  62                int insert_new, int *occupied)
  63{
  64        /*
  65         * Both diff_tree_remote() and diff_tree_local() tend to process
  66         * merge_pairs in ascending order. Therefore, cache last returned
  67         * index, and search sequentially from there until the appropriate
  68         * position is found.
  69         *
  70         * Since inserts only happen from diff_tree_remote() (which mainly
  71         * _appends_), we don't care that inserting into the middle of the
  72         * list is expensive (using memmove()).
  73         */
  74        static int last_index;
  75        int i = last_index < len ? last_index : len - 1;
  76        int prev_cmp = 0, cmp = -1;
  77        while (i >= 0 && i < len) {
  78                cmp = oidcmp(obj, &list[i].obj);
  79                if (!cmp) /* obj belongs @ i */
  80                        break;
  81                else if (cmp < 0 && prev_cmp <= 0) /* obj belongs < i */
  82                        i--;
  83                else if (cmp < 0) /* obj belongs between i-1 and i */
  84                        break;
  85                else if (cmp > 0 && prev_cmp >= 0) /* obj belongs > i */
  86                        i++;
  87                else /* if (cmp > 0) */ { /* obj belongs between i and i+1 */
  88                        i++;
  89                        break;
  90                }
  91                prev_cmp = cmp;
  92        }
  93        if (i < 0)
  94                i = 0;
  95        /* obj belongs at, or immediately preceding, index i (0 <= i <= len) */
  96
  97        if (!cmp)
  98                *occupied = 1;
  99        else {
 100                *occupied = 0;
 101                if (insert_new && i < len) {
 102                        MOVE_ARRAY(list + i + 1, list + i, len - i);
 103                        memset(list + i, 0, sizeof(struct notes_merge_pair));
 104                }
 105        }
 106        last_index = i;
 107        return list + i;
 108}
 109
 110static struct object_id uninitialized = {
 111        "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" \
 112        "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
 113};
 114
 115static struct notes_merge_pair *diff_tree_remote(struct notes_merge_options *o,
 116                                                 const struct object_id *base,
 117                                                 const struct object_id *remote,
 118                                                 int *num_changes)
 119{
 120        struct diff_options opt;
 121        struct notes_merge_pair *changes;
 122        int i, len = 0;
 123
 124        trace_printf("\tdiff_tree_remote(base = %.7s, remote = %.7s)\n",
 125               oid_to_hex(base), oid_to_hex(remote));
 126
 127        diff_setup(&opt);
 128        opt.flags.recursive = 1;
 129        opt.output_format = DIFF_FORMAT_NO_OUTPUT;
 130        diff_setup_done(&opt);
 131        diff_tree_oid(base, remote, "", &opt);
 132        diffcore_std(&opt);
 133
 134        changes = xcalloc(diff_queued_diff.nr, sizeof(struct notes_merge_pair));
 135
 136        for (i = 0; i < diff_queued_diff.nr; i++) {
 137                struct diff_filepair *p = diff_queued_diff.queue[i];
 138                struct notes_merge_pair *mp;
 139                int occupied;
 140                struct object_id obj;
 141
 142                if (verify_notes_filepair(p, &obj)) {
 143                        trace_printf("\t\tCannot merge entry '%s' (%c): "
 144                               "%.7s -> %.7s. Skipping!\n", p->one->path,
 145                               p->status, oid_to_hex(&p->one->oid),
 146                               oid_to_hex(&p->two->oid));
 147                        continue;
 148                }
 149                mp = find_notes_merge_pair_pos(changes, len, &obj, 1, &occupied);
 150                if (occupied) {
 151                        /* We've found an addition/deletion pair */
 152                        assert(!oidcmp(&mp->obj, &obj));
 153                        if (is_null_oid(&p->one->oid)) { /* addition */
 154                                assert(is_null_oid(&mp->remote));
 155                                oidcpy(&mp->remote, &p->two->oid);
 156                        } else if (is_null_oid(&p->two->oid)) { /* deletion */
 157                                assert(is_null_oid(&mp->base));
 158                                oidcpy(&mp->base, &p->one->oid);
 159                        } else
 160                                assert(!"Invalid existing change recorded");
 161                } else {
 162                        oidcpy(&mp->obj, &obj);
 163                        oidcpy(&mp->base, &p->one->oid);
 164                        oidcpy(&mp->local, &uninitialized);
 165                        oidcpy(&mp->remote, &p->two->oid);
 166                        len++;
 167                }
 168                trace_printf("\t\tStored remote change for %s: %.7s -> %.7s\n",
 169                       oid_to_hex(&mp->obj), oid_to_hex(&mp->base),
 170                       oid_to_hex(&mp->remote));
 171        }
 172        diff_flush(&opt);
 173        clear_pathspec(&opt.pathspec);
 174
 175        *num_changes = len;
 176        return changes;
 177}
 178
 179static void diff_tree_local(struct notes_merge_options *o,
 180                            struct notes_merge_pair *changes, int len,
 181                            const struct object_id *base,
 182                            const struct object_id *local)
 183{
 184        struct diff_options opt;
 185        int i;
 186
 187        trace_printf("\tdiff_tree_local(len = %i, base = %.7s, local = %.7s)\n",
 188               len, oid_to_hex(base), oid_to_hex(local));
 189
 190        diff_setup(&opt);
 191        opt.flags.recursive = 1;
 192        opt.output_format = DIFF_FORMAT_NO_OUTPUT;
 193        diff_setup_done(&opt);
 194        diff_tree_oid(base, local, "", &opt);
 195        diffcore_std(&opt);
 196
 197        for (i = 0; i < diff_queued_diff.nr; i++) {
 198                struct diff_filepair *p = diff_queued_diff.queue[i];
 199                struct notes_merge_pair *mp;
 200                int match;
 201                struct object_id obj;
 202
 203                if (verify_notes_filepair(p, &obj)) {
 204                        trace_printf("\t\tCannot merge entry '%s' (%c): "
 205                               "%.7s -> %.7s. Skipping!\n", p->one->path,
 206                               p->status, oid_to_hex(&p->one->oid),
 207                               oid_to_hex(&p->two->oid));
 208                        continue;
 209                }
 210                mp = find_notes_merge_pair_pos(changes, len, &obj, 0, &match);
 211                if (!match) {
 212                        trace_printf("\t\tIgnoring local-only change for %s: "
 213                               "%.7s -> %.7s\n", oid_to_hex(&obj),
 214                               oid_to_hex(&p->one->oid),
 215                               oid_to_hex(&p->two->oid));
 216                        continue;
 217                }
 218
 219                assert(!oidcmp(&mp->obj, &obj));
 220                if (is_null_oid(&p->two->oid)) { /* deletion */
 221                        /*
 222                         * Either this is a true deletion (1), or it is part
 223                         * of an A/D pair (2), or D/A pair (3):
 224                         *
 225                         * (1) mp->local is uninitialized; set it to null_sha1
 226                         * (2) mp->local is not uninitialized; don't touch it
 227                         * (3) mp->local is uninitialized; set it to null_sha1
 228                         *     (will be overwritten by following addition)
 229                         */
 230                        if (!oidcmp(&mp->local, &uninitialized))
 231                                oidclr(&mp->local);
 232                } else if (is_null_oid(&p->one->oid)) { /* addition */
 233                        /*
 234                         * Either this is a true addition (1), or it is part
 235                         * of an A/D pair (2), or D/A pair (3):
 236                         *
 237                         * (1) mp->local is uninitialized; set to p->two->sha1
 238                         * (2) mp->local is uninitialized; set to p->two->sha1
 239                         * (3) mp->local is null_sha1;     set to p->two->sha1
 240                         */
 241                        assert(is_null_oid(&mp->local) ||
 242                               !oidcmp(&mp->local, &uninitialized));
 243                        oidcpy(&mp->local, &p->two->oid);
 244                } else { /* modification */
 245                        /*
 246                         * This is a true modification. p->one->sha1 shall
 247                         * match mp->base, and mp->local shall be uninitialized.
 248                         * Set mp->local to p->two->sha1.
 249                         */
 250                        assert(!oidcmp(&p->one->oid, &mp->base));
 251                        assert(!oidcmp(&mp->local, &uninitialized));
 252                        oidcpy(&mp->local, &p->two->oid);
 253                }
 254                trace_printf("\t\tStored local change for %s: %.7s -> %.7s\n",
 255                       oid_to_hex(&mp->obj), oid_to_hex(&mp->base),
 256                       oid_to_hex(&mp->local));
 257        }
 258        diff_flush(&opt);
 259        clear_pathspec(&opt.pathspec);
 260}
 261
 262static void check_notes_merge_worktree(struct notes_merge_options *o)
 263{
 264        if (!o->has_worktree) {
 265                /*
 266                 * Must establish NOTES_MERGE_WORKTREE.
 267                 * Abort if NOTES_MERGE_WORKTREE already exists
 268                 */
 269                if (file_exists(git_path(NOTES_MERGE_WORKTREE)) &&
 270                    !is_empty_dir(git_path(NOTES_MERGE_WORKTREE))) {
 271                        if (advice_resolve_conflict)
 272                                die(_("You have not concluded your previous "
 273                                    "notes merge (%s exists).\nPlease, use "
 274                                    "'git notes merge --commit' or 'git notes "
 275                                    "merge --abort' to commit/abort the "
 276                                    "previous merge before you start a new "
 277                                    "notes merge."), git_path("NOTES_MERGE_*"));
 278                        else
 279                                die(_("You have not concluded your notes merge "
 280                                    "(%s exists)."), git_path("NOTES_MERGE_*"));
 281                }
 282
 283                if (safe_create_leading_directories_const(git_path(
 284                                NOTES_MERGE_WORKTREE "/.test")))
 285                        die_errno("unable to create directory %s",
 286                                  git_path(NOTES_MERGE_WORKTREE));
 287                o->has_worktree = 1;
 288        } else if (!file_exists(git_path(NOTES_MERGE_WORKTREE)))
 289                /* NOTES_MERGE_WORKTREE should already be established */
 290                die("missing '%s'. This should not happen",
 291                    git_path(NOTES_MERGE_WORKTREE));
 292}
 293
 294static void write_buf_to_worktree(const struct object_id *obj,
 295                                  const char *buf, unsigned long size)
 296{
 297        int fd;
 298        char *path = git_pathdup(NOTES_MERGE_WORKTREE "/%s", oid_to_hex(obj));
 299        if (safe_create_leading_directories_const(path))
 300                die_errno("unable to create directory for '%s'", path);
 301
 302        fd = xopen(path, O_WRONLY | O_EXCL | O_CREAT, 0666);
 303
 304        while (size > 0) {
 305                ssize_t ret = write_in_full(fd, buf, size);
 306                if (ret < 0) {
 307                        /* Ignore epipe */
 308                        if (errno == EPIPE)
 309                                break;
 310                        die_errno("notes-merge");
 311                }
 312                size -= ret;
 313                buf += ret;
 314        }
 315
 316        close(fd);
 317        free(path);
 318}
 319
 320static void write_note_to_worktree(const struct object_id *obj,
 321                                   const struct object_id *note)
 322{
 323        enum object_type type;
 324        unsigned long size;
 325        void *buf = read_object_file(note, &type, &size);
 326
 327        if (!buf)
 328                die("cannot read note %s for object %s",
 329                    oid_to_hex(note), oid_to_hex(obj));
 330        if (type != OBJ_BLOB)
 331                die("blob expected in note %s for object %s",
 332                    oid_to_hex(note), oid_to_hex(obj));
 333        write_buf_to_worktree(obj, buf, size);
 334        free(buf);
 335}
 336
 337static int ll_merge_in_worktree(struct notes_merge_options *o,
 338                                struct notes_merge_pair *p)
 339{
 340        mmbuffer_t result_buf;
 341        mmfile_t base, local, remote;
 342        int status;
 343
 344        read_mmblob(&base, &p->base);
 345        read_mmblob(&local, &p->local);
 346        read_mmblob(&remote, &p->remote);
 347
 348        status = ll_merge(&result_buf, oid_to_hex(&p->obj), &base, NULL,
 349                          &local, o->local_ref, &remote, o->remote_ref, NULL);
 350
 351        free(base.ptr);
 352        free(local.ptr);
 353        free(remote.ptr);
 354
 355        if ((status < 0) || !result_buf.ptr)
 356                die("Failed to execute internal merge");
 357
 358        write_buf_to_worktree(&p->obj, result_buf.ptr, result_buf.size);
 359        free(result_buf.ptr);
 360
 361        return status;
 362}
 363
 364static int merge_one_change_manual(struct notes_merge_options *o,
 365                                   struct notes_merge_pair *p,
 366                                   struct notes_tree *t)
 367{
 368        const char *lref = o->local_ref ? o->local_ref : "local version";
 369        const char *rref = o->remote_ref ? o->remote_ref : "remote version";
 370
 371        trace_printf("\t\t\tmerge_one_change_manual(obj = %.7s, base = %.7s, "
 372               "local = %.7s, remote = %.7s)\n",
 373               oid_to_hex(&p->obj), oid_to_hex(&p->base),
 374               oid_to_hex(&p->local), oid_to_hex(&p->remote));
 375
 376        /* add "Conflicts:" section to commit message first time through */
 377        if (!o->has_worktree)
 378                strbuf_addstr(&(o->commit_msg), "\n\nConflicts:\n");
 379
 380        strbuf_addf(&(o->commit_msg), "\t%s\n", oid_to_hex(&p->obj));
 381
 382        if (o->verbosity >= 2)
 383                printf("Auto-merging notes for %s\n", oid_to_hex(&p->obj));
 384        check_notes_merge_worktree(o);
 385        if (is_null_oid(&p->local)) {
 386                /* D/F conflict, checkout p->remote */
 387                assert(!is_null_oid(&p->remote));
 388                if (o->verbosity >= 1)
 389                        printf("CONFLICT (delete/modify): Notes for object %s "
 390                                "deleted in %s and modified in %s. Version from %s "
 391                                "left in tree.\n",
 392                                oid_to_hex(&p->obj), lref, rref, rref);
 393                write_note_to_worktree(&p->obj, &p->remote);
 394        } else if (is_null_oid(&p->remote)) {
 395                /* D/F conflict, checkout p->local */
 396                assert(!is_null_oid(&p->local));
 397                if (o->verbosity >= 1)
 398                        printf("CONFLICT (delete/modify): Notes for object %s "
 399                                "deleted in %s and modified in %s. Version from %s "
 400                                "left in tree.\n",
 401                                oid_to_hex(&p->obj), rref, lref, lref);
 402                write_note_to_worktree(&p->obj, &p->local);
 403        } else {
 404                /* "regular" conflict, checkout result of ll_merge() */
 405                const char *reason = "content";
 406                if (is_null_oid(&p->base))
 407                        reason = "add/add";
 408                assert(!is_null_oid(&p->local));
 409                assert(!is_null_oid(&p->remote));
 410                if (o->verbosity >= 1)
 411                        printf("CONFLICT (%s): Merge conflict in notes for "
 412                                "object %s\n", reason,
 413                                oid_to_hex(&p->obj));
 414                ll_merge_in_worktree(o, p);
 415        }
 416
 417        trace_printf("\t\t\tremoving from partial merge result\n");
 418        remove_note(t, p->obj.hash);
 419
 420        return 1;
 421}
 422
 423static int merge_one_change(struct notes_merge_options *o,
 424                            struct notes_merge_pair *p, struct notes_tree *t)
 425{
 426        /*
 427         * Return 0 if change is successfully resolved (stored in notes_tree).
 428         * Return 1 is change results in a conflict (NOT stored in notes_tree,
 429         * but instead written to NOTES_MERGE_WORKTREE with conflict markers).
 430         */
 431        switch (o->strategy) {
 432        case NOTES_MERGE_RESOLVE_MANUAL:
 433                return merge_one_change_manual(o, p, t);
 434        case NOTES_MERGE_RESOLVE_OURS:
 435                if (o->verbosity >= 2)
 436                        printf("Using local notes for %s\n",
 437                                                oid_to_hex(&p->obj));
 438                /* nothing to do */
 439                return 0;
 440        case NOTES_MERGE_RESOLVE_THEIRS:
 441                if (o->verbosity >= 2)
 442                        printf("Using remote notes for %s\n",
 443                                                oid_to_hex(&p->obj));
 444                if (add_note(t, &p->obj, &p->remote, combine_notes_overwrite))
 445                        BUG("combine_notes_overwrite failed");
 446                return 0;
 447        case NOTES_MERGE_RESOLVE_UNION:
 448                if (o->verbosity >= 2)
 449                        printf("Concatenating local and remote notes for %s\n",
 450                                                        oid_to_hex(&p->obj));
 451                if (add_note(t, &p->obj, &p->remote, combine_notes_concatenate))
 452                        die("failed to concatenate notes "
 453                            "(combine_notes_concatenate)");
 454                return 0;
 455        case NOTES_MERGE_RESOLVE_CAT_SORT_UNIQ:
 456                if (o->verbosity >= 2)
 457                        printf("Concatenating unique lines in local and remote "
 458                                "notes for %s\n", oid_to_hex(&p->obj));
 459                if (add_note(t, &p->obj, &p->remote, combine_notes_cat_sort_uniq))
 460                        die("failed to concatenate notes "
 461                            "(combine_notes_cat_sort_uniq)");
 462                return 0;
 463        }
 464        die("Unknown strategy (%i).", o->strategy);
 465}
 466
 467static int merge_changes(struct notes_merge_options *o,
 468                         struct notes_merge_pair *changes, int *num_changes,
 469                         struct notes_tree *t)
 470{
 471        int i, conflicts = 0;
 472
 473        trace_printf("\tmerge_changes(num_changes = %i)\n", *num_changes);
 474        for (i = 0; i < *num_changes; i++) {
 475                struct notes_merge_pair *p = changes + i;
 476                trace_printf("\t\t%.7s: %.7s -> %.7s/%.7s\n",
 477                       oid_to_hex(&p->obj), oid_to_hex(&p->base),
 478                       oid_to_hex(&p->local),
 479                       oid_to_hex(&p->remote));
 480
 481                if (!oidcmp(&p->base, &p->remote)) {
 482                        /* no remote change; nothing to do */
 483                        trace_printf("\t\t\tskipping (no remote change)\n");
 484                } else if (!oidcmp(&p->local, &p->remote)) {
 485                        /* same change in local and remote; nothing to do */
 486                        trace_printf("\t\t\tskipping (local == remote)\n");
 487                } else if (!oidcmp(&p->local, &uninitialized) ||
 488                           !oidcmp(&p->local, &p->base)) {
 489                        /* no local change; adopt remote change */
 490                        trace_printf("\t\t\tno local change, adopted remote\n");
 491                        if (add_note(t, &p->obj, &p->remote,
 492                                     combine_notes_overwrite))
 493                                BUG("combine_notes_overwrite failed");
 494                } else {
 495                        /* need file-level merge between local and remote */
 496                        trace_printf("\t\t\tneed content-level merge\n");
 497                        conflicts += merge_one_change(o, p, t);
 498                }
 499        }
 500
 501        return conflicts;
 502}
 503
 504static int merge_from_diffs(struct notes_merge_options *o,
 505                            const struct object_id *base,
 506                            const struct object_id *local,
 507                            const struct object_id *remote,
 508                            struct notes_tree *t)
 509{
 510        struct notes_merge_pair *changes;
 511        int num_changes, conflicts;
 512
 513        trace_printf("\tmerge_from_diffs(base = %.7s, local = %.7s, "
 514               "remote = %.7s)\n", oid_to_hex(base), oid_to_hex(local),
 515               oid_to_hex(remote));
 516
 517        changes = diff_tree_remote(o, base, remote, &num_changes);
 518        diff_tree_local(o, changes, num_changes, base, local);
 519
 520        conflicts = merge_changes(o, changes, &num_changes, t);
 521        free(changes);
 522
 523        if (o->verbosity >= 4)
 524                printf(t->dirty ?
 525                       "Merge result: %i unmerged notes and a dirty notes tree\n" :
 526                       "Merge result: %i unmerged notes and a clean notes tree\n",
 527                       conflicts);
 528
 529        return conflicts ? -1 : 1;
 530}
 531
 532int notes_merge(struct notes_merge_options *o,
 533                struct notes_tree *local_tree,
 534                struct object_id *result_oid)
 535{
 536        struct object_id local_oid, remote_oid;
 537        struct commit *local, *remote;
 538        struct commit_list *bases = NULL;
 539        const struct object_id *base_oid, *base_tree_oid;
 540        int result = 0;
 541
 542        assert(o->local_ref && o->remote_ref);
 543        assert(!strcmp(o->local_ref, local_tree->ref));
 544        oidclr(result_oid);
 545
 546        trace_printf("notes_merge(o->local_ref = %s, o->remote_ref = %s)\n",
 547               o->local_ref, o->remote_ref);
 548
 549        /* Dereference o->local_ref into local_sha1 */
 550        if (read_ref_full(o->local_ref, 0, &local_oid, NULL))
 551                die("Failed to resolve local notes ref '%s'", o->local_ref);
 552        else if (!check_refname_format(o->local_ref, 0) &&
 553                is_null_oid(&local_oid))
 554                local = NULL; /* local_oid == null_oid indicates unborn ref */
 555        else if (!(local = lookup_commit_reference(&local_oid)))
 556                die("Could not parse local commit %s (%s)",
 557                    oid_to_hex(&local_oid), o->local_ref);
 558        trace_printf("\tlocal commit: %.7s\n", oid_to_hex(&local_oid));
 559
 560        /* Dereference o->remote_ref into remote_oid */
 561        if (get_oid(o->remote_ref, &remote_oid)) {
 562                /*
 563                 * Failed to get remote_oid. If o->remote_ref looks like an
 564                 * unborn ref, perform the merge using an empty notes tree.
 565                 */
 566                if (!check_refname_format(o->remote_ref, 0)) {
 567                        oidclr(&remote_oid);
 568                        remote = NULL;
 569                } else {
 570                        die("Failed to resolve remote notes ref '%s'",
 571                            o->remote_ref);
 572                }
 573        } else if (!(remote = lookup_commit_reference(&remote_oid))) {
 574                die("Could not parse remote commit %s (%s)",
 575                    oid_to_hex(&remote_oid), o->remote_ref);
 576        }
 577        trace_printf("\tremote commit: %.7s\n", oid_to_hex(&remote_oid));
 578
 579        if (!local && !remote)
 580                die("Cannot merge empty notes ref (%s) into empty notes ref "
 581                    "(%s)", o->remote_ref, o->local_ref);
 582        if (!local) {
 583                /* result == remote commit */
 584                oidcpy(result_oid, &remote_oid);
 585                goto found_result;
 586        }
 587        if (!remote) {
 588                /* result == local commit */
 589                oidcpy(result_oid, &local_oid);
 590                goto found_result;
 591        }
 592        assert(local && remote);
 593
 594        /* Find merge bases */
 595        bases = get_merge_bases(local, remote);
 596        if (!bases) {
 597                base_oid = &null_oid;
 598                base_tree_oid = the_hash_algo->empty_tree;
 599                if (o->verbosity >= 4)
 600                        printf("No merge base found; doing history-less merge\n");
 601        } else if (!bases->next) {
 602                base_oid = &bases->item->object.oid;
 603                base_tree_oid = get_commit_tree_oid(bases->item);
 604                if (o->verbosity >= 4)
 605                        printf("One merge base found (%.7s)\n",
 606                               oid_to_hex(base_oid));
 607        } else {
 608                /* TODO: How to handle multiple merge-bases? */
 609                base_oid = &bases->item->object.oid;
 610                base_tree_oid = get_commit_tree_oid(bases->item);
 611                if (o->verbosity >= 3)
 612                        printf("Multiple merge bases found. Using the first "
 613                                "(%.7s)\n", oid_to_hex(base_oid));
 614        }
 615
 616        if (o->verbosity >= 4)
 617                printf("Merging remote commit %.7s into local commit %.7s with "
 618                        "merge-base %.7s\n", oid_to_hex(&remote->object.oid),
 619                        oid_to_hex(&local->object.oid),
 620                        oid_to_hex(base_oid));
 621
 622        if (!oidcmp(&remote->object.oid, base_oid)) {
 623                /* Already merged; result == local commit */
 624                if (o->verbosity >= 2)
 625                        printf("Already up to date!\n");
 626                oidcpy(result_oid, &local->object.oid);
 627                goto found_result;
 628        }
 629        if (!oidcmp(&local->object.oid, base_oid)) {
 630                /* Fast-forward; result == remote commit */
 631                if (o->verbosity >= 2)
 632                        printf("Fast-forward\n");
 633                oidcpy(result_oid, &remote->object.oid);
 634                goto found_result;
 635        }
 636
 637        result = merge_from_diffs(o, base_tree_oid,
 638                                  get_commit_tree_oid(local),
 639                                  get_commit_tree_oid(remote), local_tree);
 640
 641        if (result != 0) { /* non-trivial merge (with or without conflicts) */
 642                /* Commit (partial) result */
 643                struct commit_list *parents = NULL;
 644                commit_list_insert(remote, &parents); /* LIFO order */
 645                commit_list_insert(local, &parents);
 646                create_notes_commit(local_tree, parents, o->commit_msg.buf,
 647                                    o->commit_msg.len, result_oid);
 648        }
 649
 650found_result:
 651        free_commit_list(bases);
 652        strbuf_release(&(o->commit_msg));
 653        trace_printf("notes_merge(): result = %i, result_oid = %.7s\n",
 654               result, oid_to_hex(result_oid));
 655        return result;
 656}
 657
 658int notes_merge_commit(struct notes_merge_options *o,
 659                       struct notes_tree *partial_tree,
 660                       struct commit *partial_commit,
 661                       struct object_id *result_oid)
 662{
 663        /*
 664         * Iterate through files in .git/NOTES_MERGE_WORKTREE and add all
 665         * found notes to 'partial_tree'. Write the updated notes tree to
 666         * the DB, and commit the resulting tree object while reusing the
 667         * commit message and parents from 'partial_commit'.
 668         * Finally store the new commit object OID into 'result_oid'.
 669         */
 670        DIR *dir;
 671        struct dirent *e;
 672        struct strbuf path = STRBUF_INIT;
 673        const char *buffer = get_commit_buffer(partial_commit, NULL);
 674        const char *msg = strstr(buffer, "\n\n");
 675        int baselen;
 676
 677        git_path_buf(&path, NOTES_MERGE_WORKTREE);
 678        if (o->verbosity >= 3)
 679                printf("Committing notes in notes merge worktree at %s\n",
 680                        path.buf);
 681
 682        if (!msg || msg[2] == '\0')
 683                die("partial notes commit has empty message");
 684        msg += 2;
 685
 686        dir = opendir(path.buf);
 687        if (!dir)
 688                die_errno("could not open %s", path.buf);
 689
 690        strbuf_addch(&path, '/');
 691        baselen = path.len;
 692        while ((e = readdir(dir)) != NULL) {
 693                struct stat st;
 694                struct object_id obj_oid, blob_oid;
 695
 696                if (is_dot_or_dotdot(e->d_name))
 697                        continue;
 698
 699                if (get_oid_hex(e->d_name, &obj_oid)) {
 700                        if (o->verbosity >= 3)
 701                                printf("Skipping non-SHA1 entry '%s%s'\n",
 702                                        path.buf, e->d_name);
 703                        continue;
 704                }
 705
 706                strbuf_addstr(&path, e->d_name);
 707                /* write file as blob, and add to partial_tree */
 708                if (stat(path.buf, &st))
 709                        die_errno("Failed to stat '%s'", path.buf);
 710                if (index_path(&blob_oid, path.buf, &st, HASH_WRITE_OBJECT))
 711                        die("Failed to write blob object from '%s'", path.buf);
 712                if (add_note(partial_tree, &obj_oid, &blob_oid, NULL))
 713                        die("Failed to add resolved note '%s' to notes tree",
 714                            path.buf);
 715                if (o->verbosity >= 4)
 716                        printf("Added resolved note for object %s: %s\n",
 717                                oid_to_hex(&obj_oid), oid_to_hex(&blob_oid));
 718                strbuf_setlen(&path, baselen);
 719        }
 720
 721        create_notes_commit(partial_tree, partial_commit->parents, msg,
 722                            strlen(msg), result_oid);
 723        unuse_commit_buffer(partial_commit, buffer);
 724        if (o->verbosity >= 4)
 725                printf("Finalized notes merge commit: %s\n",
 726                        oid_to_hex(result_oid));
 727        strbuf_release(&path);
 728        closedir(dir);
 729        return 0;
 730}
 731
 732int notes_merge_abort(struct notes_merge_options *o)
 733{
 734        /*
 735         * Remove all files within .git/NOTES_MERGE_WORKTREE. We do not remove
 736         * the .git/NOTES_MERGE_WORKTREE directory itself, since it might be
 737         * the current working directory of the user.
 738         */
 739        struct strbuf buf = STRBUF_INIT;
 740        int ret;
 741
 742        git_path_buf(&buf, NOTES_MERGE_WORKTREE);
 743        if (o->verbosity >= 3)
 744                printf("Removing notes merge worktree at %s/*\n", buf.buf);
 745        ret = remove_dir_recursively(&buf, REMOVE_DIR_KEEP_TOPLEVEL);
 746        strbuf_release(&buf);
 747        return ret;
 748}