Make sure get_sha1 does not accept ambiguous sha1 prefix (again).

diff --git a/read-tree.c b/read-tree.c
index ca808739dba4235f0f8a5777ff4bbfe4443d1d27..5fdf58d240e68f2c4b332dbdd02be357641127f8 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -13,6 +13,8 @@
 static int merge = 0;
 static int update = 0;
 static int index_only = 0;
+static int nontrivial_merge = 0;
+static int trivial_merges_only = 0;
 
 static int head_idx = -1;
 static int merge_size = 0;
@@ -275,6 +277,9 @@ static int unpack_trees(merge_fn_t fn)
        if (unpack_trees_rec(posns, len, "", fn, &indpos))
                return -1;
 
+       if (trivial_merges_only && nontrivial_merge)
+               die("Merge requires file-level merging");
+
        check_updates(active_cache, active_nr);
        return 0;
 }
@@ -460,6 +465,8 @@ static int threeway_merge(struct cache_entry **stages)
                verify_uptodate(index);
        }
 
+       nontrivial_merge = 1;
+
        /* #2, #3, #4, #6, #7, #9, #11. */
        count = 0;
        if (!head_match || !remote_match) {
@@ -629,9 +636,9 @@ int main(int argc, char **argv)
                        continue;
                }
 
-               if (!strcmp(arg, "--head")) {
-                       head_idx = stage - 1;
-                       fn = threeway_merge;
+               if (!strcmp(arg, "--trivial")) {
+                       trivial_merges_only = 1;
+                       continue;
                }
 
                /* "-m" stands for "merge", meaning we start in stage 1 */
@@ -657,7 +664,8 @@ int main(int argc, char **argv)
        }
        if ((update||index_only) && !merge)
                usage(read_tree_usage);
-       if (merge && !fn) {
+
+       if (merge) {
                if (stage < 2)
                        die("just how do you expect me to merge %d trees?", stage-1);
                switch (stage - 1) {
@@ -674,9 +682,7 @@ int main(int argc, char **argv)
                        fn = threeway_merge;
                        break;
                }
-       }
 
-       if (head_idx < 0) {
                if (stage - 1 >= 3)
                        head_idx = stage - 2;
                else