From a7256debd4b6ba9f6ccb94c0958ef48cdd8cb664 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nguy=E1=BB=85n=20Th=C3=A1i=20Ng=E1=BB=8Dc=20Duy?= Date: Tue, 19 Mar 2019 16:39:10 +0700 Subject: checkout.txt: note about losing staged changes with --merge MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If you have staged changes in path A and perform 'checkout --merge' (which could result in conflicts in a totally unrelated path B), changes in A will be gone. Which is unexpected. We are supposed to keep all changes, or kick and scream otherwise. This is the result of how --merge is implemented, from the very first day in 1be0659efc (checkout: merge local modifications while switching branches., 2006-01-12): 1. a merge is done, unmerged entries are collected 2. a hard switch to a new branch is done, then unmerged entries added back There is no trivial fix for this. Going with 3-way merge one file at a time loses rename detection. Going with 3-way merge by trees requires teaching the algorithm to pick up staged changes. And even if we detect staged changes with --merge and abort for safety, an option to continue --merge is very weird. Such an option would keep worktree changes, but drop staged changes. Because the problem has been with us since the introduction of --merge and everybody has been pretty happy (except Phillip, who found this problem), I'll just take a note here to acknowledge it and wait for merge wizards to come in and work their magic. There may be a way forward [1]. [1] CABPp-BFoL_U=bzON4SEMaQSKU2TKwnOgNqjt5MUaOejTKGUJxw@mail.gmail.com Reported-by: Phillip Wood Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano --- builtin/checkout.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'builtin') diff --git a/builtin/checkout.c b/builtin/checkout.c index 24b8593b93..a56fa534f1 100644 --- a/builtin/checkout.c +++ b/builtin/checkout.c @@ -676,6 +676,8 @@ static int merge_working_tree(const struct checkout_opts *opts, struct tree *result; struct tree *work; struct merge_options o; + struct strbuf sb = STRBUF_INIT; + if (!opts->merge) return 1; @@ -686,6 +688,13 @@ static int merge_working_tree(const struct checkout_opts *opts, if (!old_branch_info->commit) return 1; + if (repo_index_has_changes(the_repository, + get_commit_tree(old_branch_info->commit), + &sb)) + warning(_("staged changes in the following files may be lost: %s"), + sb.buf); + strbuf_release(&sb); + /* Do more real merge */ /* -- cgit v1.2.3