Merge branch 'en/dirty-merge-fixes'

The recursive merge strategy did not properly ensure there was no
change between HEAD and the index before performing its operation,
which has been corrected.

* en/dirty-merge-fixes:
  merge: fix misleading pre-merge check documentation
  merge-recursive: enforce rule that index matches head before merging
  t6044: add more testcases with staged changes before a merge is invoked
  merge-recursive: fix assumption that head tree being merged is HEAD
  merge-recursive: make sure when we say we abort that we actually abort
  t6044: add a testcase for index matching head, when head doesn't match HEAD
  t6044: verify that merges expected to abort actually abort
  index_has_changes(): avoid assuming operating on the_index
  read-cache.c: move index_has_changes() from merge.c

1 files changed, 7 insertions, 7 deletions

diff --git a/merge-recursive.c b/merge-recursive.c
index 07d792fd1..1446e92be 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3281,6 +3281,13 @@ int merge_trees(struct merge_options *o,
 		struct tree **result)
 {
 	int code, clean;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (!o->call_depth && index_has_changes(&the_index, head, &sb)) {
+		err(o, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
+		    sb.buf);
+		return -1;
+	}
 
 	if (o->subtree_shift) {
 		merge = shift_tree_object(head, merge, o->subtree_shift);
@@ -3288,13 +3295,6 @@ int merge_trees(struct merge_options *o,
 	}
 
 	if (oid_eq(&common->object.oid, &merge->object.oid)) {
-		struct strbuf sb = STRBUF_INIT;
-
-		if (!o->call_depth && index_has_changes(&sb)) {
-			err(o, _("Dirty index: cannot merge (dirty: %s)"),
-			    sb.buf);
-			return 0;
-		}
 		output(o, 0, _("Already up to date!"));
 		*result = head;
 		return 1;