Merge branch 'jt/submodule-pull-recurse-rebase'
[gitweb.git] / merge-recursive.c
index f7478622f25d31afc3ad2e433d837b8a78e183ba..ac27abbd4cd708fdc2526c6508680b7d246773b6 100644 (file)
@@ -23,6 +23,7 @@
 #include "merge-recursive.h"
 #include "dir.h"
 #include "submodule.h"
+#include "revision.h"
 
 struct path_hashmap_entry {
        struct hashmap_entry e;
@@ -162,7 +163,7 @@ static struct commit *make_virtual_commit(struct tree *tree, const char *comment
        struct commit *commit = alloc_commit_node();
 
        set_merge_remote_desc(commit, comment, (struct object *)commit);
-       commit->tree = tree;
+       commit->maybe_tree = tree;
        commit->object.parsed = 1;
        return commit;
 }
@@ -337,10 +338,10 @@ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
        init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int git_merge_trees(struct merge_options *o,
-                          struct tree *common,
-                          struct tree *head,
-                          struct tree *merge)
+static int unpack_trees_start(struct merge_options *o,
+                             struct tree *common,
+                             struct tree *head,
+                             struct tree *merge)
 {
        int rc;
        struct tree_desc t[3];
@@ -356,6 +357,7 @@ static int git_merge_trees(struct merge_options *o,
        o->unpack_opts.fn = threeway_merge;
        o->unpack_opts.src_index = &the_index;
        o->unpack_opts.dst_index = &tmp_index;
+       o->unpack_opts.aggressive = !merge_detect_rename(o);
        setup_unpack_trees_porcelain(&o->unpack_opts, "merge");
 
        init_tree_desc_from_tree(t+0, common);
@@ -378,6 +380,12 @@ static int git_merge_trees(struct merge_options *o,
        return rc;
 }
 
+static void unpack_trees_finish(struct merge_options *o)
+{
+       discard_index(&o->orig_index);
+       clear_unpack_trees_porcelain(&o->unpack_opts);
+}
+
 struct tree *write_tree_from_memory(struct merge_options *o)
 {
        struct tree *result = NULL;
@@ -391,7 +399,7 @@ struct tree *write_tree_from_memory(struct merge_options *o)
                                fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
                                        (int)ce_namelen(ce), ce->name);
                }
-               die("BUG: unmerged index entries in merge-recursive.c");
+               BUG("unmerged index entries in merge-recursive.c");
        }
 
        if (!active_cache_tree)
@@ -779,6 +787,25 @@ static int dir_in_way(const char *path, int check_working_copy, int empty_ok)
                !(empty_ok && is_empty_dir(path));
 }
 
+/*
+ * Returns whether path was tracked in the index before the merge started,
+ * and its oid and mode match the specified values
+ */
+static int was_tracked_and_matches(struct merge_options *o, const char *path,
+                                  const struct object_id *oid, unsigned mode)
+{
+       int pos = index_name_pos(&o->orig_index, path, strlen(path));
+       struct cache_entry *ce;
+
+       if (0 > pos)
+               /* we were not tracking this path before the merge */
+               return 0;
+
+       /* See if the file we were tracking before matches */
+       ce = o->orig_index.cache[pos];
+       return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
+}
+
 /*
  * Returns whether path was tracked in the index before the merge started
  */
@@ -842,9 +869,9 @@ static int was_dirty(struct merge_options *o, const char *path)
        if (o->call_depth || !was_tracked(o, path))
                return !dirty;
 
-       ce = cache_file_exists(path, strlen(path), ignore_case);
-       dirty = (ce->ce_stat_data.sd_mtime.sec > 0 &&
-                verify_uptodate(ce, &o->unpack_opts) != 0);
+       ce = index_file_exists(o->unpack_opts.src_index,
+                              path, strlen(path), ignore_case);
+       dirty = verify_uptodate(ce, &o->unpack_opts) != 0;
        return dirty;
 }
 
@@ -1062,13 +1089,193 @@ static int merge_3way(struct merge_options *o,
        return merge_status;
 }
 
+static int find_first_merges(struct object_array *result, const char *path,
+               struct commit *a, struct commit *b)
+{
+       int i, j;
+       struct object_array merges = OBJECT_ARRAY_INIT;
+       struct commit *commit;
+       int contains_another;
+
+       char merged_revision[42];
+       const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
+                                  "--all", merged_revision, NULL };
+       struct rev_info revs;
+       struct setup_revision_opt rev_opts;
+
+       memset(result, 0, sizeof(struct object_array));
+       memset(&rev_opts, 0, sizeof(rev_opts));
+
+       /* get all revisions that merge commit a */
+       xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
+                       oid_to_hex(&a->object.oid));
+       init_revisions(&revs, NULL);
+       rev_opts.submodule = path;
+       /* FIXME: can't handle linked worktrees in submodules yet */
+       revs.single_worktree = path != NULL;
+       setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
+
+       /* save all revisions from the above list that contain b */
+       if (prepare_revision_walk(&revs))
+               die("revision walk setup failed");
+       while ((commit = get_revision(&revs)) != NULL) {
+               struct object *o = &(commit->object);
+               if (in_merge_bases(b, commit))
+                       add_object_array(o, NULL, &merges);
+       }
+       reset_revision_walk();
+
+       /* Now we've got all merges that contain a and b. Prune all
+        * merges that contain another found merge and save them in
+        * result.
+        */
+       for (i = 0; i < merges.nr; i++) {
+               struct commit *m1 = (struct commit *) merges.objects[i].item;
+
+               contains_another = 0;
+               for (j = 0; j < merges.nr; j++) {
+                       struct commit *m2 = (struct commit *) merges.objects[j].item;
+                       if (i != j && in_merge_bases(m2, m1)) {
+                               contains_another = 1;
+                               break;
+                       }
+               }
+
+               if (!contains_another)
+                       add_object_array(merges.objects[i].item, NULL, result);
+       }
+
+       object_array_clear(&merges);
+       return result->nr;
+}
+
+static void print_commit(struct commit *commit)
+{
+       struct strbuf sb = STRBUF_INIT;
+       struct pretty_print_context ctx = {0};
+       ctx.date_mode.type = DATE_NORMAL;
+       format_commit_message(commit, " %h: %m %s", &sb, &ctx);
+       fprintf(stderr, "%s\n", sb.buf);
+       strbuf_release(&sb);
+}
+
+static int merge_submodule(struct merge_options *o,
+                          struct object_id *result, const char *path,
+                          const struct object_id *base, const struct object_id *a,
+                          const struct object_id *b)
+{
+       struct commit *commit_base, *commit_a, *commit_b;
+       int parent_count;
+       struct object_array merges;
+
+       int i;
+       int search = !o->call_depth;
+
+       /* store a in result in case we fail */
+       oidcpy(result, a);
+
+       /* we can not handle deletion conflicts */
+       if (is_null_oid(base))
+               return 0;
+       if (is_null_oid(a))
+               return 0;
+       if (is_null_oid(b))
+               return 0;
+
+       if (add_submodule_odb(path)) {
+               output(o, 1, _("Failed to merge submodule %s (not checked out)"), path);
+               return 0;
+       }
+
+       if (!(commit_base = lookup_commit_reference(base)) ||
+           !(commit_a = lookup_commit_reference(a)) ||
+           !(commit_b = lookup_commit_reference(b))) {
+               output(o, 1, _("Failed to merge submodule %s (commits not present)"), path);
+               return 0;
+       }
+
+       /* check whether both changes are forward */
+       if (!in_merge_bases(commit_base, commit_a) ||
+           !in_merge_bases(commit_base, commit_b)) {
+               output(o, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
+               return 0;
+       }
+
+       /* Case #1: a is contained in b or vice versa */
+       if (in_merge_bases(commit_a, commit_b)) {
+               oidcpy(result, b);
+               if (show(o, 3)) {
+                       output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+                       output_commit_title(o, commit_b);
+               } else if (show(o, 2))
+                       output(o, 2, _("Fast-forwarding submodule %s to %s"), path, oid_to_hex(b));
+               else
+                       ; /* no output */
+
+               return 1;
+       }
+       if (in_merge_bases(commit_b, commit_a)) {
+               oidcpy(result, a);
+               if (show(o, 3)) {
+                       output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+                       output_commit_title(o, commit_a);
+               } else if (show(o, 2))
+                       output(o, 2, _("Fast-forwarding submodule %s to %s"), path, oid_to_hex(a));
+               else
+                       ; /* no output */
+
+               return 1;
+       }
+
+       /*
+        * Case #2: There are one or more merges that contain a and b in
+        * the submodule. If there is only one, then present it as a
+        * suggestion to the user, but leave it marked unmerged so the
+        * user needs to confirm the resolution.
+        */
+
+       /* Skip the search if makes no sense to the calling context.  */
+       if (!search)
+               return 0;
+
+       /* find commit which merges them */
+       parent_count = find_first_merges(&merges, path, commit_a, commit_b);
+       switch (parent_count) {
+       case 0:
+               output(o, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
+               break;
+
+       case 1:
+               output(o, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
+               output(o, 2, _("Found a possible merge resolution for the submodule:\n"));
+               print_commit((struct commit *) merges.objects[0].item);
+               output(o, 2, _(
+                       "If this is correct simply add it to the index "
+                       "for example\n"
+                       "by using:\n\n"
+                       "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
+                       "which will accept this suggestion.\n"),
+                       oid_to_hex(&merges.objects[0].item->oid), path);
+               break;
+
+       default:
+               output(o, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
+               for (i = 0; i < merges.nr; i++)
+                       print_commit((struct commit *) merges.objects[i].item);
+       }
+
+       object_array_clear(&merges);
+       return 0;
+}
+
 static int merge_file_1(struct merge_options *o,
-                                          const struct diff_filespec *one,
-                                          const struct diff_filespec *a,
-                                          const struct diff_filespec *b,
-                                          const char *branch1,
-                                          const char *branch2,
-                                          struct merge_file_info *result)
+                       const struct diff_filespec *one,
+                       const struct diff_filespec *a,
+                       const struct diff_filespec *b,
+                       const char *filename,
+                       const char *branch1,
+                       const char *branch2,
+                       struct merge_file_info *result)
 {
        result->merge = 0;
        result->clean = 1;
@@ -1124,12 +1331,11 @@ static int merge_file_1(struct merge_options *o,
                                return ret;
                        result->clean = (merge_status == 0);
                } else if (S_ISGITLINK(a->mode)) {
-                       result->clean = merge_submodule(&result->oid,
+                       result->clean = merge_submodule(o, &result->oid,
                                                       one->path,
                                                       &one->oid,
                                                       &a->oid,
-                                                      &b->oid,
-                                                      !o->call_depth);
+                                                      &b->oid);
                } else if (S_ISLNK(a->mode)) {
                        switch (o->recursive_variant) {
                        case MERGE_RECURSIVE_NORMAL:
@@ -1145,21 +1351,25 @@ static int merge_file_1(struct merge_options *o,
                                break;
                        }
                } else
-                       die("BUG: unsupported object type in the tree");
+                       BUG("unsupported object type in the tree");
        }
 
+       if (result->merge)
+               output(o, 2, _("Auto-merging %s"), filename);
+
        return 0;
 }
 
 static int merge_file_special_markers(struct merge_options *o,
-                          const struct diff_filespec *one,
-                          const struct diff_filespec *a,
-                          const struct diff_filespec *b,
-                          const char *branch1,
-                          const char *filename1,
-                          const char *branch2,
-                          const char *filename2,
-                          struct merge_file_info *mfi)
+                                     const struct diff_filespec *one,
+                                     const struct diff_filespec *a,
+                                     const struct diff_filespec *b,
+                                     const char *target_filename,
+                                     const char *branch1,
+                                     const char *filename1,
+                                     const char *branch2,
+                                     const char *filename2,
+                                     struct merge_file_info *mfi)
 {
        char *side1 = NULL;
        char *side2 = NULL;
@@ -1170,22 +1380,23 @@ static int merge_file_special_markers(struct merge_options *o,
        if (filename2)
                side2 = xstrfmt("%s:%s", branch2, filename2);
 
-       ret = merge_file_1(o, one, a, b,
+       ret = merge_file_1(o, one, a, b, target_filename,
                           side1 ? side1 : branch1,
                           side2 ? side2 : branch2, mfi);
+
        free(side1);
        free(side2);
        return ret;
 }
 
 static int merge_file_one(struct merge_options *o,
-                                        const char *path,
-                                        const struct object_id *o_oid, int o_mode,
-                                        const struct object_id *a_oid, int a_mode,
-                                        const struct object_id *b_oid, int b_mode,
-                                        const char *branch1,
-                                        const char *branch2,
-                                        struct merge_file_info *mfi)
+                         const char *path,
+                         const struct object_id *o_oid, int o_mode,
+                         const struct object_id *a_oid, int a_mode,
+                         const struct object_id *b_oid, int b_mode,
+                         const char *branch1,
+                         const char *branch2,
+                         struct merge_file_info *mfi)
 {
        struct diff_filespec one, a, b;
 
@@ -1196,7 +1407,7 @@ static int merge_file_one(struct merge_options *o,
        a.mode = a_mode;
        oidcpy(&b.oid, b_oid);
        b.mode = b_mode;
-       return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
+       return merge_file_1(o, &one, &a, &b, path, branch1, branch2, mfi);
 }
 
 static int conflict_rename_dir(struct merge_options *o,
@@ -1474,6 +1685,8 @@ static int conflict_rename_rename_2to1(struct merge_options *o,
        struct diff_filespec *c1 = ci->pair1->two;
        struct diff_filespec *c2 = ci->pair2->two;
        char *path = c1->path; /* == c2->path */
+       char *path_side_1_desc;
+       char *path_side_2_desc;
        struct merge_file_info mfi_c1;
        struct merge_file_info mfi_c2;
        int ret;
@@ -1487,13 +1700,19 @@ static int conflict_rename_rename_2to1(struct merge_options *o,
        remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
        remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
 
+       path_side_1_desc = xstrfmt("%s (was %s)", path, a->path);
+       path_side_2_desc = xstrfmt("%s (was %s)", path, b->path);
        if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
+                                      path_side_1_desc,
                                       o->branch1, c1->path,
                                       o->branch2, ci->ren1_other.path, &mfi_c1) ||
            merge_file_special_markers(o, b, &ci->ren2_other, c2,
+                                      path_side_2_desc,
                                       o->branch1, ci->ren2_other.path,
                                       o->branch2, c2->path, &mfi_c2))
                return -1;
+       free(path_side_1_desc);
+       free(path_side_2_desc);
 
        if (o->call_depth) {
                /*
@@ -1570,7 +1789,15 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
        diff_setup(&opts);
        opts.flags.recursive = 1;
        opts.flags.rename_empty = 0;
-       opts.detect_rename = DIFF_DETECT_RENAME;
+       opts.detect_rename = merge_detect_rename(o);
+       /*
+        * We do not have logic to handle the detection of copies.  In
+        * fact, it may not even make sense to add such logic: would we
+        * really want a change to a base file to be propagated through
+        * multiple other files by a merge?
+        */
+       if (opts.detect_rename > DIFF_DETECT_RENAME)
+               opts.detect_rename = DIFF_DETECT_RENAME;
        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
                            1000;
@@ -2377,7 +2604,7 @@ static int process_renames(struct merge_options *o,
                        const char *ren2_dst = ren2->pair->two->path;
                        enum rename_type rename_type;
                        if (strcmp(ren1_src, ren2_src) != 0)
-                               die("BUG: ren1_src != ren2_src");
+                               BUG("ren1_src != ren2_src");
                        ren2->dst_entry->processed = 1;
                        ren2->processed = 1;
                        if (strcmp(ren1_dst, ren2_dst) != 0) {
@@ -2411,7 +2638,7 @@ static int process_renames(struct merge_options *o,
                        ren2 = lookup->util;
                        ren2_dst = ren2->pair->two->path;
                        if (strcmp(ren1_dst, ren2_dst) != 0)
-                               die("BUG: ren1_dst != ren2_dst");
+                               BUG("ren1_dst != ren2_dst");
 
                        clean_merge = 0;
                        ren2->processed = 1;
@@ -2610,7 +2837,7 @@ static int handle_renames(struct merge_options *o,
        ri->head_renames = NULL;
        ri->merge_renames = NULL;
 
-       if (!o->detect_rename)
+       if (!merge_detect_rename(o))
                return 1;
 
        head_pairs = get_diffpairs(o, common, head);
@@ -2802,30 +3029,26 @@ static int merge_content(struct merge_options *o,
                               S_ISGITLINK(pair1->two->mode)))
                        df_conflict_remains = 1;
        }
-       if (merge_file_special_markers(o, &one, &a, &b,
+       if (merge_file_special_markers(o, &one, &a, &b, path,
                                       o->branch1, path1,
                                       o->branch2, path2, &mfi))
                return -1;
 
-       if (mfi.clean && !df_conflict_remains &&
-           oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
-               int path_renamed_outside_HEAD;
+       /*
+        * We can skip updating the working tree file iff:
+        *   a) The merge is clean
+        *   b) The merge matches what was in HEAD (content, mode, pathname)
+        *   c) The target path is usable (i.e. not involved in D/F conflict)
+        */
+       if (mfi.clean &&
+           was_tracked_and_matches(o, path, &mfi.oid, mfi.mode) &&
+           !df_conflict_remains) {
                output(o, 3, _("Skipped %s (merged same as existing)"), path);
-               /*
-                * The content merge resulted in the same file contents we
-                * already had.  We can return early if those file contents
-                * are recorded at the correct path (which may not be true
-                * if the merge involves a rename).
-                */
-               path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
-               if (!path_renamed_outside_HEAD) {
-                       if (add_cacheinfo(o, mfi.mode, &mfi.oid, path,
-                                         0, (!o->call_depth && !is_dirty), 0))
-                               return -1;
-                       return mfi.clean;
-               }
-       } else
-               output(o, 2, _("Auto-merging %s"), path);
+               if (add_cacheinfo(o, mfi.mode, &mfi.oid, path,
+                                 0, (!o->call_depth && !is_dirty), 0))
+                       return -1;
+               return mfi.clean;
+       }
 
        if (!mfi.clean) {
                if (S_ISGITLINK(mfi.mode))
@@ -3019,7 +3242,7 @@ static int process_entry(struct merge_options *o,
                 */
                remove_file(o, 1, path, !a_mode);
        } else
-               die("BUG: fatal merge failure, shouldn't happen.");
+               BUG("fatal merge failure, shouldn't happen.");
 
        return clean_merge;
 }
@@ -3050,13 +3273,14 @@ int merge_trees(struct merge_options *o,
                return 1;
        }
 
-       code = git_merge_trees(o, common, head, merge);
+       code = unpack_trees_start(o, common, head, merge);
 
        if (code != 0) {
                if (show(o, 4) || o->call_depth)
                        err(o, _("merging of trees %s and %s failed"),
                            oid_to_hex(&head->object.oid),
                            oid_to_hex(&merge->object.oid));
+               unpack_trees_finish(o);
                return -1;
        }
 
@@ -3097,7 +3321,7 @@ int merge_trees(struct merge_options *o,
                for (i = 0; i < entries->nr; i++) {
                        struct stage_data *e = entries->items[i].util;
                        if (!e->processed)
-                               die("BUG: unprocessed path??? %s",
+                               BUG("unprocessed path??? %s",
                                    entries->items[i].string);
                }
 
@@ -3109,20 +3333,15 @@ int merge_trees(struct merge_options *o,
 
                hashmap_free(&o->current_file_dir_set, 1);
 
-               if (clean < 0)
+               if (clean < 0) {
+                       unpack_trees_finish(o);
                        return clean;
+               }
        }
        else
                clean = 1;
 
-       /* Free the extra index left from git_merge_trees() */
-       /*
-        * FIXME: Need to also free data allocated by
-        * setup_unpack_trees_porcelain() tucked away in o->unpack_opts.msgs,
-        * but the problem is that only half of it refers to dynamically
-        * allocated data, while the other half points at static strings.
-        */
-       discard_index(&o->orig_index);
+       unpack_trees_finish(o);
 
        if (o->call_depth && !(*result = write_tree_from_memory(o)))
                return -1;
@@ -3217,7 +3436,8 @@ int merge_recursive(struct merge_options *o,
                read_cache();
 
        o->ancestor = "merged common ancestors";
-       clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
+       clean = merge_trees(o, get_commit_tree(h1), get_commit_tree(h2),
+                           get_commit_tree(merged_common_ancestors),
                            &mrtree);
        if (clean < 0) {
                flush_output(o);
@@ -3295,9 +3515,18 @@ int merge_recursive_generic(struct merge_options *o,
 
 static void merge_recursive_config(struct merge_options *o)
 {
+       char *value = NULL;
        git_config_get_int("merge.verbosity", &o->verbosity);
        git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
        git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
+       if (!git_config_get_string("diff.renames", &value)) {
+               o->diff_detect_rename = git_config_rename("diff.renames", value);
+               free(value);
+       }
+       if (!git_config_get_string("merge.renames", &value)) {
+               o->merge_detect_rename = git_config_rename("merge.renames", value);
+               free(value);
+       }
        git_config(git_xmerge_config, NULL);
 }
 
@@ -3310,7 +3539,8 @@ void init_merge_options(struct merge_options *o)
        o->diff_rename_limit = -1;
        o->merge_rename_limit = -1;
        o->renormalize = 0;
-       o->detect_rename = 1;
+       o->diff_detect_rename = -1;
+       o->merge_detect_rename = -1;
        merge_recursive_config(o);
        merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
        if (merge_verbosity)
@@ -3361,16 +3591,16 @@ int parse_merge_opt(struct merge_options *o, const char *s)
        else if (!strcmp(s, "no-renormalize"))
                o->renormalize = 0;
        else if (!strcmp(s, "no-renames"))
-               o->detect_rename = 0;
+               o->merge_detect_rename = 0;
        else if (!strcmp(s, "find-renames")) {
-               o->detect_rename = 1;
+               o->merge_detect_rename = 1;
                o->rename_score = 0;
        }
        else if (skip_prefix(s, "find-renames=", &arg) ||
                 skip_prefix(s, "rename-threshold=", &arg)) {
                if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
                        return -1;
-               o->detect_rename = 1;
+               o->merge_detect_rename = 1;
        }
        else
                return -1;