path: root/Documentation/git-read-tree.txt
diff options
authorJunio C Hamano <>2008-09-08 02:49:25 (GMT)
committerJunio C Hamano <>2008-09-10 05:55:22 (GMT)
commit5521883490e85f4d973141972cf16f89a79f1979 (patch)
tree650ba77fc5225db197582c4adb7eac754059b698 /Documentation/git-read-tree.txt
parentaaefbfa66c348a461b3081873ef42819c8b38dac (diff)
checkout: do not lose staged removal
The logic to checkout a different commit implements the safety to never lose user's local changes. For example, switching from a commit to another commit, when you have changed a path that is different between them, need to merge your changes to the version from the switched-to commit, which you may not necessarily be able to resolve easily. By default, "git checkout" refused to switch branches, to give you a chance to stash your local changes (or use "-m" to merge, accepting the risks of getting conflicts). This safety, however, had one deliberate hole since early June 2005. When your local change was to remove a path (and optionally to stage that removal), the command checked out the path from the switched-to commit nevertheless. This was to allow an initial checkout to happen smoothly (e.g. an initial checkout is done by starting with an empty index and switching from the commit at the HEAD to the same commit). We can tighten the rule slightly to allow this special case to pass, without losing sight of removal explicitly done by the user, by noticing if the index is truly empty when the operation begins. For historical background, see: This case is marked as *0* in the message, which both Linus and I said "it feels somewhat wrong but otherwise we cannot start from an empty index". Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'Documentation/git-read-tree.txt')
1 files changed, 10 insertions, 1 deletions
diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt
index 6f4b9b0..309deac 100644
--- a/Documentation/git-read-tree.txt
+++ b/Documentation/git-read-tree.txt
@@ -160,7 +160,10 @@ Here are the "carry forward" rules:
0 nothing nothing nothing (does not happen)
1 nothing nothing exists use M
2 nothing exists nothing remove path from index
- 3 nothing exists exists use M
+ 3 nothing exists exists, use M if "initial checkout"
+ H == M keep index otherwise
+ exists fail
+ H != M
clean I==H I==M
@@ -207,6 +210,12 @@ you picked it up via e-mail in a patch form), `git diff-index
merge, but it would not show in `git diff-index --cached $M`
output after two-tree merge.
+Case #3 is slightly tricky and needs explanation. The result from this
+rule logically should be to remove the path if the user staged the removal
+of the path and then swiching to a new branch. That however will prevent
+the initial checkout from happening, so the rule is modified to use M (new
+tree) only when the contents of the index is empty. Otherwise the removal
+of the path is kept as long as $H and $M are the same.
3-Way Merge