Documentation: --cherry-pick
[gitweb.git] / merge-recursive.c
index 52370213092c13bd02988493b21489ec61fb2593..3096594b3e9f07785229236700c6039efd61c305 100644 (file)
 #include "path-list.h"
 #include "xdiff-interface.h"
 
+static int subtree_merge;
+
+static struct tree *shift_tree_object(struct tree *one, struct tree *two)
+{
+       unsigned char shifted[20];
+
+       /*
+        * NEEDSWORK: this limits the recursion depth to hardcoded
+        * value '2' to avoid excessive overhead.
+        */
+       shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
+       if (!hashcmp(two->object.sha1, shifted))
+               return two;
+       return lookup_tree(shifted);
+}
+
 /*
  * A virtual commit has
  * - (const char *)commit->util set to the name, and
@@ -67,27 +83,75 @@ struct stage_data
        unsigned processed:1;
 };
 
+struct output_buffer
+{
+       struct output_buffer *next;
+       char *str;
+};
+
 static struct path_list current_file_set = {NULL, 0, 0, 1};
 static struct path_list current_directory_set = {NULL, 0, 0, 1};
 
-static int output_indent = 0;
+static int call_depth = 0;
+static int verbosity = 2;
+static int buffer_output = 1;
+static int do_progress = 1;
+static unsigned last_percent;
+static unsigned merged_cnt;
+static unsigned total_cnt;
+static volatile sig_atomic_t progress_update;
+static struct output_buffer *output_list, *output_end;
+
+static int show (int v)
+{
+       return (!call_depth && verbosity >= v) || verbosity >= 5;
+}
 
-static void output(const char *fmt, ...)
+static void output(int v, const char *fmt, ...)
 {
        va_list args;
-       int i;
-       for (i = output_indent; i--;)
-               fputs("  ", stdout);
        va_start(args, fmt);
-       vfprintf(stdout, fmt, args);
+       if (buffer_output && show(v)) {
+               struct output_buffer *b = xmalloc(sizeof(*b));
+               nfvasprintf(&b->str, fmt, args);
+               b->next = NULL;
+               if (output_end)
+                       output_end->next = b;
+               else
+                       output_list = b;
+               output_end = b;
+       } else if (show(v)) {
+               int i;
+               for (i = call_depth; i--;)
+                       fputs("  ", stdout);
+               vfprintf(stdout, fmt, args);
+               fputc('\n', stdout);
+       }
        va_end(args);
-       fputc('\n', stdout);
+}
+
+static void flush_output()
+{
+       struct output_buffer *b, *n;
+       for (b = output_list; b; b = n) {
+               int i;
+               for (i = call_depth; i--;)
+                       fputs("  ", stdout);
+               fputs(b->str, stdout);
+               fputc('\n', stdout);
+               n = b->next;
+               free(b->str);
+               free(b);
+       }
+       output_list = NULL;
+       output_end = NULL;
 }
 
 static void output_commit_title(struct commit *commit)
 {
        int i;
-       for (i = output_indent; i--;)
+       flush_output();
+       for (i = call_depth; i--;)
                fputs("  ", stdout);
        if (commit->util)
                printf("virtual %s\n", (char *)commit->util);
@@ -110,6 +174,39 @@ static void output_commit_title(struct commit *commit)
        }
 }
 
+static void progress_interval(int signum)
+{
+       progress_update = 1;
+}
+
+static void setup_progress_signal(void)
+{
+       struct sigaction sa;
+       struct itimerval v;
+
+       memset(&sa, 0, sizeof(sa));
+       sa.sa_handler = progress_interval;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       sigaction(SIGALRM, &sa, NULL);
+
+       v.it_interval.tv_sec = 1;
+       v.it_interval.tv_usec = 0;
+       v.it_value = v.it_interval;
+       setitimer(ITIMER_REAL, &v, NULL);
+}
+
+static void display_progress()
+{
+       unsigned percent = total_cnt ? merged_cnt * 100 / total_cnt : 0;
+       if (progress_update || percent != last_percent) {
+               fprintf(stderr, "%4u%% (%u/%u) done\r",
+                       percent, merged_cnt, total_cnt);
+               progress_update = 0;
+               last_percent = percent;
+       }
+}
+
 static struct cache_entry *make_cache_entry(unsigned int mode,
                const unsigned char *sha1, const char *path, int stage, int refresh)
 {
@@ -140,7 +237,7 @@ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
        struct cache_entry *ce;
        ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
        if (!ce)
-               return error("cache_addinfo failed: %s", strerror(cache_errno));
+               return error("addinfo_cache failed for path '%s'", path);
        return add_cache_entry(ce, options);
 }
 
@@ -197,8 +294,16 @@ static struct tree *git_write_tree(void)
 {
        struct tree *result = NULL;
 
-       if (unmerged_index())
+       if (unmerged_index()) {
+               int i;
+               output(0, "There are unmerged index entries:");
+               for (i = 0; i < active_nr; i++) {
+                       struct cache_entry *ce = active_cache[i];
+                       if (ce_stage(ce))
+                               output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
+               }
                return NULL;
+       }
 
        if (!active_cache_tree)
                active_cache_tree = cache_tree();
@@ -272,11 +377,14 @@ static struct path_list *get_unmerged(void)
        int i;
 
        unmerged->strdup_paths = 1;
+       total_cnt += active_nr;
 
-       for (i = 0; i < active_nr; i++) {
+       for (i = 0; i < active_nr; i++, merged_cnt++) {
                struct path_list_item *item;
                struct stage_data *e;
                struct cache_entry *ce = active_cache[i];
+               if (do_progress)
+                       display_progress();
                if (!ce_stage(ce))
                        continue;
 
@@ -302,7 +410,7 @@ struct rename
 };
 
 /*
- * Get information of all renames which occured between 'o_tree' and
+ * 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.
@@ -476,17 +584,17 @@ static void update_file_flags(const unsigned char *sha,
                update_wd = 0;
 
        if (update_wd) {
-               char type[20];
+               enum object_type type;
                void *buf;
                unsigned long size;
 
-               buf = read_sha1_file(sha, type, &size);
+               buf = read_sha1_file(sha, &type, &size);
                if (!buf)
                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
-               if (strcmp(type, blob_type) != 0)
+               if (type != OBJ_BLOB)
                        die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 
-               if (S_ISREG(mode)) {
+               if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
                        int fd;
                        if (mkdir_p(path, 0777))
                                die("failed to create path %s: %s", path, strerror(errno));
@@ -505,8 +613,9 @@ static void update_file_flags(const unsigned char *sha,
                        memcpy(lnk, buf, size);
                        lnk[size] = '\0';
                        mkdir_p(path, 0777);
-                       unlink(lnk);
+                       unlink(path);
                        symlink(lnk, path);
+                       free(lnk);
                } else
                        die("do not know what to do with %06o %s '%s'",
                            mode, sha1_to_hex(sha), path);
@@ -536,7 +645,7 @@ struct merge_file_info
 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 {
        unsigned long size;
-       char type[20];
+       enum object_type type;
 
        if (!hashcmp(sha1, null_sha1)) {
                mm->ptr = xstrdup("");
@@ -544,8 +653,8 @@ static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
                return;
        }
 
-       mm->ptr = read_sha1_file(sha1, type, &size);
-       if (!mm->ptr || strcmp(type, blob_type))
+       mm->ptr = read_sha1_file(sha1, &type, &size);
+       if (!mm->ptr || type != OBJ_BLOB)
                die("unable to read blob object %s", sha1_to_hex(sha1));
        mm->size = size;
 }
@@ -640,18 +749,29 @@ static void conflict_rename_rename(struct rename *ren1,
        const char *dst_name2 = ren2_dst;
        if (path_list_has_path(&current_directory_set, ren1_dst)) {
                dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
-               output("%s is a directory in %s adding as %s instead",
+               output(1, "%s is a directory in %s added as %s instead",
                       ren1_dst, branch2, dst_name1);
                remove_file(0, ren1_dst, 0);
        }
        if (path_list_has_path(&current_directory_set, ren2_dst)) {
                dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
-               output("%s is a directory in %s adding as %s instead",
+               output(1, "%s is a directory in %s added as %s instead",
                       ren2_dst, branch1, dst_name2);
                remove_file(0, ren2_dst, 0);
        }
-       update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
-       update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+       if (index_only) {
+               remove_file_from_cache(dst_name1);
+               remove_file_from_cache(dst_name2);
+               /*
+                * Uncomment to leave the conflicting names in the resulting tree
+                *
+                * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
+                * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
+                */
+       } else {
+               update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
+               update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+       }
        while (delp--)
                free(del[delp]);
 }
@@ -660,7 +780,7 @@ static void conflict_rename_dir(struct rename *ren1,
                                const char *branch1)
 {
        char *new_path = unique_path(ren1->pair->two->path, branch1);
-       output("Renaming %s to %s instead", ren1->pair->one->path, new_path);
+       output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
        remove_file(0, ren1->pair->two->path, 0);
        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
        free(new_path);
@@ -673,7 +793,7 @@ static void conflict_rename_rename_2(struct rename *ren1,
 {
        char *new_path1 = unique_path(ren1->pair->two->path, branch1);
        char *new_path2 = unique_path(ren2->pair->two->path, branch2);
-       output("Renaming %s to %s and %s to %s instead",
+       output(1, "Renamed %s to %s and %s to %s instead",
               ren1->pair->one->path, new_path1,
               ren2->pair->one->path, new_path2);
        remove_file(0, ren1->pair->two->path, 0);
@@ -766,11 +886,17 @@ static int process_renames(struct path_list *a_renames,
                        ren2->processed = 1;
                        if (strcmp(ren1_dst, ren2_dst) != 0) {
                                clean_merge = 0;
-                               output("CONFLICT (rename/rename): "
-                                      "Rename %s->%s in branch %s "
-                                      "rename %s->%s in %s",
+                               output(1, "CONFLICT (rename/rename): "
+                                      "Rename \"%s\"->\"%s\" in branch \"%s\" "
+                                      "rename \"%s\"->\"%s\" in \"%s\"%s",
                                       src, ren1_dst, branch1,
-                                      src, ren2_dst, branch2);
+                                      src, ren2_dst, branch2,
+                                      index_only ? " (left unresolved)": "");
+                               if (index_only) {
+                                       remove_file_from_cache(src);
+                                       update_file(0, ren1->pair->one->sha1,
+                                                   ren1->pair->one->mode, src);
+                               }
                                conflict_rename_rename(ren1, branch1, ren2, branch2);
                        } else {
                                struct merge_file_info mfi;
@@ -781,13 +907,13 @@ static int process_renames(struct path_list *a_renames,
                                                 branch1,
                                                 branch2);
                                if (mfi.merge || !mfi.clean)
-                                       output("Renaming %s->%s", src, ren1_dst);
+                                       output(1, "Renamed %s->%s", src, ren1_dst);
 
                                if (mfi.merge)
-                                       output("Auto-merging %s", ren1_dst);
+                                       output(2, "Auto-merged %s", ren1_dst);
 
                                if (!mfi.clean) {
-                                       output("CONFLICT (content): merge conflict in %s",
+                                       output(1, "CONFLICT (content): merge conflict in %s",
                                               ren1_dst);
                                        clean_merge = 0;
 
@@ -807,7 +933,7 @@ static int process_renames(struct path_list *a_renames,
                        struct diff_filespec src_other, dst_other;
                        int try_merge, stage = a_renames == renames1 ? 3: 2;
 
-                       remove_file(1, ren1_src, index_only);
+                       remove_file(1, ren1_src, index_only || stage == 3);
 
                        hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
                        src_other.mode = ren1->src_entry->stages[stage].mode;
@@ -818,14 +944,14 @@ static int process_renames(struct path_list *a_renames,
 
                        if (path_list_has_path(&current_directory_set, ren1_dst)) {
                                clean_merge = 0;
-                               output("CONFLICT (rename/directory): Rename %s->%s in %s "
+                               output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
                                       " directory %s added in %s",
                                       ren1_src, ren1_dst, branch1,
                                       ren1_dst, branch2);
                                conflict_rename_dir(ren1, branch1);
                        } else if (sha_eq(src_other.sha1, null_sha1)) {
                                clean_merge = 0;
-                               output("CONFLICT (rename/delete): Rename %s->%s in %s "
+                               output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
                                       "and deleted in %s",
                                       ren1_src, ren1_dst, branch1,
                                       branch2);
@@ -834,19 +960,19 @@ static int process_renames(struct path_list *a_renames,
                                const char *new_path;
                                clean_merge = 0;
                                try_merge = 1;
-                               output("CONFLICT (rename/add): Rename %s->%s in %s. "
+                               output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
                                       "%s added in %s",
                                       ren1_src, ren1_dst, branch1,
                                       ren1_dst, branch2);
                                new_path = unique_path(ren1_dst, branch2);
-                               output("Adding as %s instead", new_path);
+                               output(1, "Added as %s instead", new_path);
                                update_file(0, dst_other.sha1, dst_other.mode, new_path);
                        } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
                                ren2 = item->util;
                                clean_merge = 0;
                                ren2->processed = 1;
-                               output("CONFLICT (rename/rename): Rename %s->%s in %s. "
-                                      "Rename %s->%s in %s",
+                               output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
+                                      "Renamed %s->%s in %s",
                                       ren1_src, ren1_dst, branch1,
                                       ren2->pair->one->path, ren2->pair->two->path, branch2);
                                conflict_rename_rename_2(ren1, branch1, ren2, branch2);
@@ -870,11 +996,11 @@ static int process_renames(struct path_list *a_renames,
                                                a_branch, b_branch);
 
                                if (mfi.merge || !mfi.clean)
-                                       output("Renaming %s => %s", ren1_src, ren1_dst);
+                                       output(1, "Renamed %s => %s", ren1_src, ren1_dst);
                                if (mfi.merge)
-                                       output("Auto-merging %s", ren1_dst);
+                                       output(2, "Auto-merged %s", ren1_dst);
                                if (!mfi.clean) {
-                                       output("CONFLICT (rename/modify): Merge conflict in %s",
+                                       output(1, "CONFLICT (rename/modify): Merge conflict in %s",
                                               ren1_dst);
                                        clean_merge = 0;
 
@@ -922,20 +1048,20 @@ static int process_entry(const char *path, struct stage_data *entry,
                        /* Deleted in both or deleted in one and
                         * unchanged in the other */
                        if (a_sha)
-                               output("Removing %s", path);
+                               output(2, "Removed %s", path);
                        /* do not touch working file if it did not exist */
                        remove_file(1, path, !a_sha);
                } else {
                        /* Deleted in one and changed in the other */
                        clean_merge = 0;
                        if (!a_sha) {
-                               output("CONFLICT (delete/modify): %s deleted in %s "
+                               output(1, "CONFLICT (delete/modify): %s deleted in %s "
                                       "and modified in %s. Version %s of %s left in tree.",
                                       path, branch1,
                                       branch2, branch2, path);
                                update_file(0, b_sha, b_mode, path);
                        } else {
-                               output("CONFLICT (delete/modify): %s deleted in %s "
+                               output(1, "CONFLICT (delete/modify): %s deleted in %s "
                                       "and modified in %s. Version %s of %s left in tree.",
                                       path, branch2,
                                       branch1, branch1, path);
@@ -968,13 +1094,13 @@ static int process_entry(const char *path, struct stage_data *entry,
                if (path_list_has_path(&current_directory_set, path)) {
                        const char *new_path = unique_path(path, add_branch);
                        clean_merge = 0;
-                       output("CONFLICT (%s): There is a directory with name %s in %s. "
-                              "Adding %s as %s",
+                       output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
+                              "Added %s as %s",
                               conf, path, other_branch, path, new_path);
                        remove_file(0, path, 0);
                        update_file(0, sha, mode, new_path);
                } else {
-                       output("Adding %s", path);
+                       output(2, "Added %s", path);
                        update_file(1, sha, mode, path);
                }
        } else if (a_sha && b_sha) {
@@ -988,7 +1114,7 @@ static int process_entry(const char *path, struct stage_data *entry,
                        reason = "add/add";
                        o_sha = (unsigned char *)null_sha1;
                }
-               output("Auto-merging %s", path);
+               output(2, "Auto-merged %s", path);
                o.path = a.path = b.path = (char *)path;
                hashcpy(o.sha1, o_sha);
                o.mode = o_mode;
@@ -1004,7 +1130,7 @@ static int process_entry(const char *path, struct stage_data *entry,
                        update_file(1, mfi.sha, mfi.mode, path);
                else {
                        clean_merge = 0;
-                       output("CONFLICT (%s): Merge conflict in %s",
+                       output(1, "CONFLICT (%s): Merge conflict in %s",
                                        reason, path);
 
                        if (index_only)
@@ -1027,8 +1153,14 @@ static int merge_trees(struct tree *head,
                       struct tree **result)
 {
        int code, clean;
+
+       if (subtree_merge) {
+               merge = shift_tree_object(head, merge);
+               common = shift_tree_object(head, common);
+       }
+
        if (sha_eq(common->object.sha1, merge->object.sha1)) {
-               output("Already uptodate!");
+               output(0, "Already uptodate!");
                *result = head;
                return 1;
        }
@@ -1053,26 +1185,25 @@ static int merge_trees(struct tree *head,
                re_merge = get_renames(merge, common, head, merge, entries);
                clean = process_renames(re_head, re_merge,
                                branch1, branch2);
-               for (i = 0; i < entries->nr; i++) {
+               total_cnt += entries->nr;
+               for (i = 0; i < entries->nr; i++, merged_cnt++) {
                        const char *path = entries->items[i].path;
                        struct stage_data *e = entries->items[i].util;
-                       if (e->processed)
-                               continue;
-                       if (!process_entry(path, e, branch1, branch2))
+                       if (!e->processed
+                               && !process_entry(path, e, branch1, branch2))
                                clean = 0;
+                       if (do_progress)
+                               display_progress();
                }
 
                path_list_clear(re_merge, 0);
                path_list_clear(re_head, 0);
                path_list_clear(entries, 1);
 
-       } else {
-               clean = 1;
-               printf("merging of trees %s and %s resulted in %s\n",
-                      sha1_to_hex(head->object.sha1),
-                      sha1_to_hex(merge->object.sha1),
-                      sha1_to_hex((*result)->object.sha1));
        }
+       else
+               clean = 1;
+
        if (index_only)
                *result = git_write_tree();
 
@@ -1092,13 +1223,12 @@ static struct commit_list *reverse_commit_list(struct commit_list *list)
 
 /*
  * Merge the commits h1 and h2, return the resulting virtual
- * commit object and a flag indicating the cleaness of the merge.
+ * commit object and a flag indicating the cleanness of the merge.
  */
 static int merge(struct commit *h1,
                 struct commit *h2,
                 const char *branch1,
                 const char *branch2,
-                int call_depth /* =0 */,
                 struct commit_list *ca,
                 struct commit **result)
 {
@@ -1107,18 +1237,22 @@ static int merge(struct commit *h1,
        struct tree *mrtree;
        int clean;
 
-       output("Merging:");
-       output_commit_title(h1);
-       output_commit_title(h2);
+       if (show(4)) {
+               output(4, "Merging:");
+               output_commit_title(h1);
+               output_commit_title(h2);
+       }
 
        if (!ca) {
                ca = get_merge_bases(h1, h2, 1);
                ca = reverse_commit_list(ca);
        }
 
-       output("found %u common ancestor(s):", commit_list_count(ca));
-       for (iter = ca; iter; iter = iter->next)
-               output_commit_title(iter->item);
+       if (show(5)) {
+               output(5, "found %u common ancestor(s):", commit_list_count(ca));
+               for (iter = ca; iter; iter = iter->next)
+                       output_commit_title(iter->item);
+       }
 
        merged_common_ancestors = pop_commit(&ca);
        if (merged_common_ancestors == NULL) {
@@ -1127,34 +1261,33 @@ static int merge(struct commit *h1,
 
                tree->object.parsed = 1;
                tree->object.type = OBJ_TREE;
-               write_sha1_file(NULL, 0, tree_type, tree->object.sha1);
+               pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
        }
 
        for (iter = ca; iter; iter = iter->next) {
-               output_indent = call_depth + 1;
+               call_depth++;
                /*
                 * When the merge fails, the result contains files
                 * with conflict markers. The cleanness flag is
-                * ignored, it was never acutally used, as result of
-                * merge_trees has always overwritten it: the commited
+                * ignored, it was never actually used, as result of
+                * merge_trees has always overwritten it: the committed
                 * "conflicts" were already resolved.
                 */
                discard_cache();
                merge(merged_common_ancestors, iter->item,
                      "Temporary merge branch 1",
                      "Temporary merge branch 2",
-                     call_depth + 1,
                      NULL,
                      &merged_common_ancestors);
-               output_indent = call_depth;
+               call_depth--;
 
                if (!merged_common_ancestors)
                        die("merge returned no commit");
        }
 
        discard_cache();
-       if (call_depth == 0) {
+       if (!call_depth) {
                read_cache();
                index_only = 0;
        } else
@@ -1168,6 +1301,16 @@ static int merge(struct commit *h1,
                commit_list_insert(h1, &(*result)->parents);
                commit_list_insert(h2, &(*result)->parents->next);
        }
+       if (!call_depth && do_progress) {
+               /* Make sure we end at 100% */
+               if (!total_cnt)
+                       total_cnt = 1;
+               merged_cnt = total_cnt;
+               progress_update = 1;
+               display_progress();
+               fputc('\n', stderr);
+       }
+       flush_output();
        return clean;
 }
 
@@ -1201,6 +1344,15 @@ static struct commit *get_ref(const char *ref)
        return (struct commit *)object;
 }
 
+static int merge_config(const char *var, const char *value)
+{
+       if (!strcasecmp(var, "merge.verbosity")) {
+               verbosity = git_config_int(var, value);
+               return 0;
+       }
+       return git_default_config(var, value);
+}
+
 int main(int argc, char *argv[])
 {
        static const char *bases[20];
@@ -1212,7 +1364,16 @@ int main(int argc, char *argv[])
        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
        int index_fd;
 
-       git_config(git_default_config); /* core.filemode */
+       if (argv[0]) {
+               int namelen = strlen(argv[0]);
+               if (8 < namelen &&
+                   !strcmp(argv[0] + namelen - 8, "-subtree"))
+                       subtree_merge = 1;
+       }
+
+       git_config(merge_config);
+       if (getenv("GIT_MERGE_VERBOSITY"))
+               verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
 
        if (argc < 4)
                die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
@@ -1225,6 +1386,12 @@ int main(int argc, char *argv[])
        }
        if (argc - i != 3) /* "--" "<head>" "<remote>" */
                die("Not handling anything other than two heads merge.");
+       if (verbosity >= 5) {
+               buffer_output = 0;
+               do_progress = 0;
+       }
+       else
+               do_progress = isatty(1);
 
        branch1 = argv[++i];
        branch2 = argv[++i];
@@ -1234,19 +1401,23 @@ int main(int argc, char *argv[])
 
        branch1 = better_branch_name(branch1);
        branch2 = better_branch_name(branch2);
-       printf("Merging %s with %s\n", branch1, branch2);
 
-       index_fd = hold_lock_file_for_update(lock, get_index_file(), 1);
+       if (do_progress)
+               setup_progress_signal();
+       if (show(3))
+               printf("Merging %s with %s\n", branch1, branch2);
+
+       index_fd = hold_locked_index(lock, 1);
 
        for (i = 0; i < bases_count; i++) {
                struct commit *ancestor = get_ref(bases[i]);
                ca = commit_list_insert(ancestor, &ca);
        }
-       clean = merge(h1, h2, branch1, branch2, 0, ca, &result);
+       clean = merge(h1, h2, branch1, branch2, ca, &result);
 
        if (active_cache_changed &&
            (write_cache(index_fd, active_cache, active_nr) ||
-            close(index_fd) || commit_lock_file(lock)))
+            close(index_fd) || commit_locked_index(lock)))
                        die ("unable to write %s", get_index_file());
 
        return clean ? 0: 1;