git-bisect.sh: don't accidentally override existing branch "bisect"

diff --git a/cache-tree.c b/cache-tree.c
index bfc95d2dc9600083b73b61c06d2b32c983db8511..73cb3407077275f82677839d2c9e794c12833c95 100644 (file)
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -341,8 +341,11 @@ static int update_one(struct cache_tree *it,
 
        if (dryrun)
                hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
-       else
-               write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
+       else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
+               strbuf_release(&buffer);
+               return -1;
+       }
+
        strbuf_release(&buffer);
        it->entry_count = i;
 #if DEBUG
@@ -529,3 +532,58 @@ struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
        }
        return it;
 }
+
+int write_cache_as_tree(unsigned char *sha1, int missing_ok, const char *prefix)
+{
+       int entries, was_valid, newfd;
+
+       /*
+        * We can't free this memory, it becomes part of a linked list
+        * parsed atexit()
+        */
+       struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+
+       newfd = hold_locked_index(lock_file, 1);
+
+       entries = read_cache();
+       if (entries < 0)
+               return WRITE_TREE_UNREADABLE_INDEX;
+
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+
+       was_valid = cache_tree_fully_valid(active_cache_tree);
+
+       if (!was_valid) {
+               if (cache_tree_update(active_cache_tree,
+                                     active_cache, active_nr,
+                                     missing_ok, 0) < 0)
+                       return WRITE_TREE_UNMERGED_INDEX;
+               if (0 <= newfd) {
+                       if (!write_cache(newfd, active_cache, active_nr) &&
+                           !commit_lock_file(lock_file))
+                               newfd = -1;
+               }
+               /* Not being able to write is fine -- we are only interested
+                * in updating the cache-tree part, and if the next caller
+                * ends up using the old index with unupdated cache-tree part
+                * it misses the work we did here, but that is just a
+                * performance penalty and not a big deal.
+                */
+       }
+
+       if (prefix) {
+               struct cache_tree *subtree =
+                       cache_tree_find(active_cache_tree, prefix);
+               if (!subtree)
+                       return WRITE_TREE_PREFIX_ERROR;
+               hashcpy(sha1, subtree->sha1);
+       }
+       else
+               hashcpy(sha1, active_cache_tree->sha1);
+
+       if (0 <= newfd)
+               rollback_lock_file(lock_file);
+
+       return 0;
+}