checkout: prevent losing staged changes with --merge

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 22fb6c0cae89a78ef2353f33591de65c721a0120..7cd01f62be0c249911731a824805af9193664f66 100644 (file)
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -725,7 +725,10 @@ static int merge_working_tree(const struct checkout_opts *opts,
                         */
                        struct tree *result;
                        struct tree *work;
+                       struct tree *old_tree;
                        struct merge_options o;
+                       struct strbuf sb = STRBUF_INIT;
+
                        if (!opts->merge)
                                return 1;
 
@@ -735,6 +738,12 @@ static int merge_working_tree(const struct checkout_opts *opts,
                         */
                        if (!old_branch_info->commit)
                                return 1;
+                       old_tree = get_commit_tree(old_branch_info->commit);
+
+                       if (repo_index_has_changes(the_repository, old_tree, &sb))
+                               die(_("cannot continue with staged changes in "
+                                     "the following files:\n%s"), sb.buf);
+                       strbuf_release(&sb);
 
                        /* Do more real merge */
 
@@ -772,7 +781,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
                        ret = merge_trees(&o,
                                          get_commit_tree(new_branch_info->commit),
                                          work,
-                                         get_commit_tree(old_branch_info->commit),
+                                         old_tree,
                                          &result);
                        if (ret < 0)
                                exit(128);