+ return max ? xmemdupz(prev, max) : NULL;
+}
+
+/*
+ * Read the tree specified with --with-tree option
+ * (typically, HEAD) into stage #1 and then
+ * squash them down to stage #0. This is used for
+ * --error-unmatch to list and check the path patterns
+ * that were given from the command line. We are not
+ * going to write this index out.
+ */
+void overlay_tree_on_cache(const char *tree_name, const char *prefix)
+{
+ struct tree *tree;
+ unsigned char sha1[20];
+ const char **match;
+ struct cache_entry *last_stage0 = NULL;
+ int i;
+
+ if (get_sha1(tree_name, sha1))
+ die("tree-ish %s not found.", tree_name);
+ tree = parse_tree_indirect(sha1);
+ if (!tree)
+ die("bad tree-ish %s", tree_name);
+
+ /* Hoist the unmerged entries up to stage #3 to make room */
+ for (i = 0; i < active_nr; i++) {
+ struct cache_entry *ce = active_cache[i];
+ if (!ce_stage(ce))
+ continue;
+ ce->ce_flags |= CE_STAGEMASK;
+ }
+
+ if (prefix) {
+ static const char *(matchbuf[2]);
+ matchbuf[0] = prefix;
+ matchbuf [1] = NULL;
+ match = matchbuf;
+ } else
+ match = NULL;
+ if (read_tree(tree, 1, match))
+ die("unable to read tree entries %s", tree_name);
+
+ for (i = 0; i < active_nr; i++) {
+ struct cache_entry *ce = active_cache[i];
+ switch (ce_stage(ce)) {
+ case 0:
+ last_stage0 = ce;
+ /* fallthru */
+ default:
+ continue;
+ case 1:
+ /*
+ * If there is stage #0 entry for this, we do not
+ * need to show it. We use CE_UPDATE bit to mark
+ * such an entry.
+ */
+ if (last_stage0 &&
+ !strcmp(last_stage0->name, ce->name))
+ ce->ce_flags |= CE_UPDATE;
+ }
+ }
+}
+
+int report_path_error(const char *ps_matched, const char **pathspec, int prefix_offset)
+{
+ /*
+ * Make sure all pathspec matched; otherwise it is an error.
+ */
+ int num, errors = 0;
+ for (num = 0; pathspec[num]; num++) {
+ int other, found_dup;
+
+ if (ps_matched[num])
+ continue;
+ /*
+ * The caller might have fed identical pathspec
+ * twice. Do not barf on such a mistake.
+ */
+ for (found_dup = other = 0;
+ !found_dup && pathspec[other];
+ other++) {
+ if (other == num || !ps_matched[other])
+ continue;
+ if (!strcmp(pathspec[other], pathspec[num]))
+ /*
+ * Ok, we have a match already.
+ */
+ found_dup = 1;
+ }
+ if (found_dup)
+ continue;
+
+ error("pathspec '%s' did not match any file(s) known to git.",
+ pathspec[num] + prefix_offset);
+ errors++;