unpack-trees: populate cache-tree on successful merge

When we unpack trees into an existing index, we discard the old
index and replace it with the new, merged index.  Ensure that this
index has its cache-tree populated.  This will make subsequent git
status and commit commands faster.

Signed-off-by: Brian Degenhardt <bmd@bmdhacks.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
index 601d02d71f735b4247528cc45b0ea055299ee7a0..055cc19000784bdb820e7ae53ba48987ead0367a 100755 (executable)
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@ -199,6 +199,30 @@ test_expect_success 'checkout -B gives cache-tree' '
        test_cache_tree
 '
 
+test_expect_success 'merge --ff-only maintains cache-tree' '
+       git checkout current &&
+       git checkout -b changes &&
+       test_commit llamas &&
+       test_commit pachyderm &&
+       test_cache_tree &&
+       git checkout current &&
+       test_cache_tree &&
+       git merge --ff-only changes &&
+       test_cache_tree
+'
+
+test_expect_success 'merge maintains cache-tree' '
+       git checkout current &&
+       git checkout -b changes2 &&
+       test_commit alpacas &&
+       test_cache_tree &&
+       git checkout current &&
+       test_commit struthio &&
+       test_cache_tree &&
+       git merge changes2 &&
+       test_cache_tree
+'
+
 test_expect_success 'partial commit gives cache-tree' '
        git checkout -b partial no-children &&
        test_commit one &&

diff --git a/unpack-trees.c b/unpack-trees.c
index be84ba2607ad2dbdb17397869c459418abad78e4..d92f903402f0f8c448b689d26d3d5a97afc56f67 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1155,6 +1155,14 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
        o->src_index = NULL;
        ret = check_updates(o) ? (-2) : 0;
        if (o->dst_index) {
+               if (!ret) {
+                       if (!o->result.cache_tree)
+                               o->result.cache_tree = cache_tree();
+                       if (!cache_tree_fully_valid(o->result.cache_tree))
+                               cache_tree_update(&o->result,
+                                                 WRITE_TREE_SILENT |
+                                                 WRITE_TREE_REPAIR);
+               }
                discard_index(o->dst_index);
                *o->dst_index = o->result;
        } else {