92 lines
3.2 KiB
Plaintext
92 lines
3.2 KiB
Plaintext
Trivial merge rules
|
|
===================
|
|
|
|
This document describes the outcomes of the trivial merge logic in read-tree.
|
|
|
|
One-way merge
|
|
-------------
|
|
|
|
This replaces the index with a different tree, keeping the stat info
|
|
for entries that don't change, and allowing -u to make the minimum
|
|
required changes to the working tree to have it match.
|
|
|
|
index tree result
|
|
-----------------------
|
|
* (empty) (empty)
|
|
(empty) tree tree
|
|
index+ tree tree
|
|
index+ index index+
|
|
|
|
Two-way merge
|
|
-------------
|
|
|
|
|
|
|
|
Three-way merge
|
|
---------------
|
|
|
|
It is permitted for the index to lack an entry; this does not prevent
|
|
any case from applying.
|
|
|
|
If the index exists, it is an error for it not to match either the
|
|
head or (if the merge is trivial) the result.
|
|
|
|
If multiple cases apply, the one used is listed first.
|
|
|
|
A result of "no merge" means that index is left in stage 0, ancest in
|
|
stage 1, head in stage 2, and remote in stage 3 (if any of these are
|
|
empty, no entry is left for that stage). Otherwise, the given entry is
|
|
left in stage 0, and there are no other entries.
|
|
|
|
A result of "no merge" is an error if the index is not empty and not
|
|
up-to-date.
|
|
|
|
*empty* means that the tree must not have a directory-file conflict
|
|
with the entry.
|
|
|
|
For multiple ancestors or remotes, a '+' means that this case applies
|
|
even if only one ancestor or remote fits; normally, all of the
|
|
ancestors or remotes must be the same.
|
|
|
|
case ancest head remote result
|
|
----------------------------------------
|
|
1 (empty)+ (empty) (empty) (empty)
|
|
2ALT (empty)+ *empty* remote remote
|
|
2ALT (empty)+ *empty* remote remote
|
|
2 (empty)^ (empty) remote no merge
|
|
3ALT (empty)+ head *empty* head
|
|
3 (empty)^ head (empty) no merge
|
|
4 (empty)^ head remote no merge
|
|
5ALT * head head head
|
|
6 ancest^ (empty) (empty) no merge
|
|
8ALT ancest (empty) ancest (empty)
|
|
7 ancest+ (empty) remote no merge
|
|
9 ancest+ head (empty) no merge
|
|
10ALT ancest ancest (empty) (empty)
|
|
11 ancest+ head remote no merge
|
|
16 anc1/anc2 anc1 anc2 no merge
|
|
13 ancest+ head ancest head
|
|
14 ancest+ ancest remote remote
|
|
14ALT ancest+ ancest remote remote
|
|
|
|
Only #2ALT and #3ALT use *empty*, because these are the only cases
|
|
where there can be conflicts that didn't exist before. Note that we
|
|
allow directory-file conflicts between things in different stages
|
|
after the trivial merge.
|
|
|
|
A possible alternative for #6 is (empty), which would make it like
|
|
#1. This is not used, due to the likelihood that it arises due to
|
|
moving the file to multiple different locations or moving and deleting
|
|
it in different branches.
|
|
|
|
Case #1 is included for completeness, and also in case we decide to
|
|
put on '+' markings; any path that is never mentioned at all isn't
|
|
handled.
|
|
|
|
Note that #16 is when both #13 and #14 apply; in this case, we refuse
|
|
the trivial merge, because we can't tell from this data which is
|
|
right. This is a case of a reverted patch (in some direction, maybe
|
|
multiple times), and the right answer depends on looking at crossings
|
|
of history or common ancestors of the ancestors.
|
|
|
|
The status as of Sep 5 is that multiple remotes are not supported |