merge-recursive: give notice when submodule commit gets fast-forwarded
[gitweb.git] / merge-recursive.c
index 76c7a56a2d895eef96a6f66ad67d71db81dbf0bb..a9aecccb8c3d59fda25eeae2596ee6b816223bde 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;
@@ -228,7 +229,7 @@ static void output_commit_title(struct merge_options *o, struct commit *commit)
                strbuf_addf(&o->obuf, "virtual %s\n",
                        merge_remote_util(commit)->name);
        else {
-               strbuf_add_unique_abbrev(&o->obuf, commit->object.oid.hash,
+               strbuf_add_unique_abbrev(&o->obuf, &commit->object.oid,
                                         DEFAULT_ABBREV);
                strbuf_addch(&o->obuf, ' ');
                if (parse_commit(commit) != 0)
@@ -335,7 +336,7 @@ struct tree *write_tree_from_memory(struct merge_options *o)
        return result;
 }
 
-static int save_files_dirs(const unsigned char *sha1,
+static int save_files_dirs(const struct object_id *oid,
                struct strbuf *base, const char *path,
                unsigned int mode, int stage, void *context)
 {
@@ -370,12 +371,12 @@ static struct stage_data *insert_stage_data(const char *path,
 {
        struct string_list_item *item;
        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
-       get_tree_entry(o->object.oid.hash, path,
-                       e->stages[1].oid.hash, &e->stages[1].mode);
-       get_tree_entry(a->object.oid.hash, path,
-                       e->stages[2].oid.hash, &e->stages[2].mode);
-       get_tree_entry(b->object.oid.hash, path,
-                       e->stages[3].oid.hash, &e->stages[3].mode);
+       get_tree_entry(&o->object.oid, path,
+                       &e->stages[1].oid, &e->stages[1].mode);
+       get_tree_entry(&a->object.oid, path,
+                       &e->stages[2].oid, &e->stages[2].mode);
+       get_tree_entry(&b->object.oid, path,
+                       &e->stages[3].oid, &e->stages[3].mode);
        item = string_list_insert(entries, path);
        item->util = e;
        return e;
@@ -537,6 +538,75 @@ struct rename {
        unsigned processed:1;
 };
 
+/*
+ * Get information of all renames which occurred between 'o_tree' and
+ * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
+ * 'b_tree') to be able to associate the correct cache entries with
+ * the rename information. 'tree' is always equal to either a_tree or b_tree.
+ */
+static struct string_list *get_renames(struct merge_options *o,
+                                      struct tree *tree,
+                                      struct tree *o_tree,
+                                      struct tree *a_tree,
+                                      struct tree *b_tree,
+                                      struct string_list *entries)
+{
+       int i;
+       struct string_list *renames;
+       struct diff_options opts;
+
+       renames = xcalloc(1, sizeof(struct string_list));
+       if (!o->detect_rename)
+               return renames;
+
+       diff_setup(&opts);
+       opts.flags.recursive = 1;
+       opts.flags.rename_empty = 0;
+       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;
+       opts.rename_score = o->rename_score;
+       opts.show_rename_progress = o->show_rename_progress;
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       diff_setup_done(&opts);
+       diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
+       diffcore_std(&opts);
+       if (opts.needed_rename_limit > o->needed_rename_limit)
+               o->needed_rename_limit = opts.needed_rename_limit;
+       for (i = 0; i < diff_queued_diff.nr; ++i) {
+               struct string_list_item *item;
+               struct rename *re;
+               struct diff_filepair *pair = diff_queued_diff.queue[i];
+               if (pair->status != 'R') {
+                       diff_free_filepair(pair);
+                       continue;
+               }
+               re = xmalloc(sizeof(*re));
+               re->processed = 0;
+               re->pair = pair;
+               item = string_list_lookup(entries, re->pair->one->path);
+               if (!item)
+                       re->src_entry = insert_stage_data(re->pair->one->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->src_entry = item->util;
+
+               item = string_list_lookup(entries, re->pair->two->path);
+               if (!item)
+                       re->dst_entry = insert_stage_data(re->pair->two->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->dst_entry = item->util;
+               item = string_list_insert(renames, pair->one->path);
+               item->util = re;
+       }
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       diff_queued_diff.nr = 0;
+       diff_flush(&opts);
+       return renames;
+}
+
 static int update_stages(struct merge_options *opt, const char *path,
                         const struct diff_filespec *o,
                         const struct diff_filespec *a,
@@ -773,7 +843,7 @@ static int update_file_flags(struct merge_options *o,
                        goto update_index;
                }
 
-               buf = read_sha1_file(oid->hash, &type, &size);
+               buf = read_object_file(oid, &type, &size);
                if (!buf)
                        return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
                if (type != OBJ_BLOB) {
@@ -908,6 +978,185 @@ 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,
@@ -959,8 +1208,9 @@ static int merge_file_1(struct merge_options *o,
                        if ((merge_status < 0) || !result_buf.ptr)
                                ret = err(o, _("Failed to execute internal merge"));
 
-                       if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
-                                                   blob_type, result->oid.hash))
+                       if (!ret &&
+                           write_object_file(result_buf.ptr, result_buf.size,
+                                             blob_type, &result->oid))
                                ret = err(o, _("Unable to add %s to database"),
                                          a->path);
 
@@ -969,17 +1219,25 @@ 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)) {
-                       oidcpy(&result->oid, &a->oid);
-
-                       if (!oid_eq(&a->oid, &b->oid))
-                               result->clean = 0;
+                       switch (o->recursive_variant) {
+                       case MERGE_RECURSIVE_NORMAL:
+                               oidcpy(&result->oid, &a->oid);
+                               if (!oid_eq(&a->oid, &b->oid))
+                                       result->clean = 0;
+                               break;
+                       case MERGE_RECURSIVE_OURS:
+                               oidcpy(&result->oid, &a->oid);
+                               break;
+                       case MERGE_RECURSIVE_THEIRS:
+                               oidcpy(&result->oid, &b->oid);
+                               break;
+                       }
                } else
                        die("BUG: unsupported object type in the tree");
        }
@@ -1311,93 +1569,6 @@ static int conflict_rename_rename_2to1(struct merge_options *o,
        return ret;
 }
 
-/*
- * Get the diff_filepairs changed between o_tree and tree.
- */
-static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
-                                              struct tree *o_tree,
-                                              struct tree *tree)
-{
-       struct diff_queue_struct *ret;
-       struct diff_options opts;
-
-       diff_setup(&opts);
-       opts.flags.recursive = 1;
-       opts.flags.rename_empty = 0;
-       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;
-       opts.rename_score = o->rename_score;
-       opts.show_rename_progress = o->show_rename_progress;
-       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-       diff_setup_done(&opts);
-       diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
-       diffcore_std(&opts);
-       if (opts.needed_rename_limit > o->needed_rename_limit)
-               o->needed_rename_limit = opts.needed_rename_limit;
-
-       ret = xmalloc(sizeof(*ret));
-       *ret = diff_queued_diff;
-
-       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-       diff_queued_diff.nr = 0;
-       diff_queued_diff.queue = NULL;
-       diff_flush(&opts);
-       return ret;
-}
-
-/*
- * Get information of all renames which occurred in 'pairs', making use of
- * any implicit directory renames inferred from the other side of history.
- * We need the three trees in the merge ('o_tree', 'a_tree' and 'b_tree')
- * to be able to associate the correct cache entries with the rename
- * information; tree is always equal to either a_tree or b_tree.
- */
-static struct string_list *get_renames(struct merge_options *o,
-                                      struct diff_queue_struct *pairs,
-                                      struct tree *tree,
-                                      struct tree *o_tree,
-                                      struct tree *a_tree,
-                                      struct tree *b_tree,
-                                      struct string_list *entries)
-{
-       int i;
-       struct string_list *renames;
-
-       renames = xcalloc(1, sizeof(struct string_list));
-
-       for (i = 0; i < pairs->nr; ++i) {
-               struct string_list_item *item;
-               struct rename *re;
-               struct diff_filepair *pair = pairs->queue[i];
-
-               if (pair->status != 'R') {
-                       diff_free_filepair(pair);
-                       continue;
-               }
-               re = xmalloc(sizeof(*re));
-               re->processed = 0;
-               re->pair = pair;
-               item = string_list_lookup(entries, re->pair->one->path);
-               if (!item)
-                       re->src_entry = insert_stage_data(re->pair->one->path,
-                                       o_tree, a_tree, b_tree, entries);
-               else
-                       re->src_entry = item->util;
-
-               item = string_list_lookup(entries, re->pair->two->path);
-               if (!item)
-                       re->dst_entry = insert_stage_data(re->pair->two->path,
-                                       o_tree, a_tree, b_tree, entries);
-               else
-                       re->dst_entry = item->util;
-               item = string_list_insert(renames, pair->one->path);
-               item->util = re;
-       }
-       return renames;
-}
-
 static int process_renames(struct merge_options *o,
                           struct string_list *a_renames,
                           struct string_list *b_renames)
@@ -1653,75 +1824,6 @@ static int process_renames(struct merge_options *o,
        return clean_merge;
 }
 
-struct rename_info {
-       struct string_list *head_renames;
-       struct string_list *merge_renames;
-};
-
-static void initial_cleanup_rename(struct diff_queue_struct *pairs)
-{
-       free(pairs->queue);
-       free(pairs);
-}
-
-static int handle_renames(struct merge_options *o,
-                         struct tree *common,
-                         struct tree *head,
-                         struct tree *merge,
-                         struct string_list *entries,
-                         struct rename_info *ri)
-{
-       struct diff_queue_struct *head_pairs, *merge_pairs;
-       int clean;
-
-       ri->head_renames = NULL;
-       ri->merge_renames = NULL;
-
-       if (!o->detect_rename)
-               return 1;
-
-       head_pairs = get_diffpairs(o, common, head);
-       merge_pairs = get_diffpairs(o, common, merge);
-
-       ri->head_renames  = get_renames(o, head_pairs, head,
-                                        common, head, merge, entries);
-       ri->merge_renames = get_renames(o, merge_pairs, merge,
-                                        common, head, merge, entries);
-       clean = process_renames(o, ri->head_renames, ri->merge_renames);
-
-       /*
-        * Some cleanup is deferred until cleanup_renames() because the
-        * data structures are still needed and referenced in
-        * process_entry().  But there are a few things we can free now.
-        */
-       initial_cleanup_rename(head_pairs);
-       initial_cleanup_rename(merge_pairs);
-
-       return clean;
-}
-
-static void final_cleanup_rename(struct string_list *rename)
-{
-       const struct rename *re;
-       int i;
-
-       if (rename == NULL)
-               return;
-
-       for (i = 0; i < rename->nr; i++) {
-               re = rename->items[i].util;
-               diff_free_filepair(re->pair);
-       }
-       string_list_clear(rename, 1);
-       free(rename);
-}
-
-static void final_cleanup_renames(struct rename_info *re_info)
-{
-       final_cleanup_rename(re_info->head_renames);
-       final_cleanup_rename(re_info->merge_renames);
-}
-
 static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
 {
        return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
@@ -1733,7 +1835,7 @@ static int read_oid_strbuf(struct merge_options *o,
        void *buf;
        enum object_type type;
        unsigned long size;
-       buf = read_sha1_file(oid->hash, &type, &size);
+       buf = read_object_file(oid, &type, &size);
        if (!buf)
                return err(o, _("cannot read object %s"), oid_to_hex(oid));
        if (type != OBJ_BLOB) {
@@ -2081,8 +2183,7 @@ int merge_trees(struct merge_options *o,
        }
 
        if (unmerged_cache()) {
-               struct string_list *entries;
-               struct rename_info re_info;
+               struct string_list *entries, *re_head, *re_merge;
                int i;
                /*
                 * Only need the hashmap while processing entries, so
@@ -2096,8 +2197,9 @@ int merge_trees(struct merge_options *o,
                get_files_dirs(o, merge);
 
                entries = get_unmerged();
-               clean = handle_renames(o, common, head, merge, entries,
-                                      &re_info);
+               re_head  = get_renames(o, head, common, head, merge, entries);
+               re_merge = get_renames(o, merge, common, head, merge, entries);
+               clean = process_renames(o, re_head, re_merge);
                record_df_conflict_files(o, entries);
                if (clean < 0)
                        goto cleanup;
@@ -2122,13 +2224,16 @@ int merge_trees(struct merge_options *o,
                }
 
 cleanup:
-               final_cleanup_renames(&re_info);
-
+               string_list_clear(re_merge, 0);
+               string_list_clear(re_head, 0);
                string_list_clear(entries, 1);
-               free(entries);
 
                hashmap_free(&o->current_file_dir_set, 1);
 
+               free(re_merge);
+               free(re_head);
+               free(entries);
+
                if (clean < 0)
                        return clean;
        }
@@ -2164,7 +2269,7 @@ int merge_recursive(struct merge_options *o,
 {
        struct commit_list *iter;
        struct commit *merged_common_ancestors;
-       struct tree *mrtree = mrtree;
+       struct tree *mrtree;
        int clean;
 
        if (show(o, 4)) {
@@ -2292,11 +2397,13 @@ int merge_recursive_generic(struct merge_options *o,
        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
        clean = merge_recursive(o, head_commit, next_commit, ca,
                        result);
-       if (clean < 0)
+       if (clean < 0) {
+               rollback_lock_file(&lock);
                return clean;
+       }
 
-       if (active_cache_changed &&
-           write_locked_index(&the_index, &lock, COMMIT_LOCK))
+       if (write_locked_index(&the_index, &lock,
+                              COMMIT_LOCK | SKIP_IF_UNCHANGED))
                return err(o, _("Unable to write index."));
 
        return clean ? 0 : 1;