and you will end up with an index with all of the <tree1> entries in
"stage1", all of the <tree2> entries in "stage2" and all of the
-<tree3> entries in "stage3".
+<tree3> entries in "stage3". When performing a merge of another
+branch into the current branch, we use the common ancestor tree
+as <tree1>, the current branch head as <tree2>, and the other
+branch head as <tree3>.
Furthermore, `git-read-tree` has special-case logic that says: if you see
a file that matches in all respects in the following states, it
"collapses" back to "stage0":
- stage 2 and 3 are the same; take one or the other (it makes no
- difference - the same work has been done on stage 2 and 3)
+ difference - the same work has been done on our branch in
+ stage 2 and their branch in stage 3)
- stage 1 and stage 2 are the same and stage 3 is different; take
- stage 3 (some work has been done on stage 3)
+ stage 3 (our branch in stage 2 did not do anything since the
+ ancestor in stage 1 while their branch in stage 3 worked on
+ it)
- stage 1 and stage 3 are the same and stage 2 is different take
- stage 2 (some work has been done on stage 2)
+ stage 2 (we did something while they did nothing)
The `git-write-tree` command refuses to write a nonsensical tree, and it
will complain about unmerged entries if it sees a single entry that is not
trivial rules ..
You would normally use `git-merge-index` with supplied
-`git-merge-one-file` to do this last step. The script
-does not touch the files in the work tree, and the entire merge
-happens in the index file. In other words, there is no need to
-worry about what is in the working directory, since it is never
-shown and never used.
+`git-merge-one-file` to do this last step. The script updates
+the files in the working tree as it merges each path and at the
+end of a successful merge.
When you start a 3-way merge with an index file that is already
populated, it is assumed that it represents the state of the
file that does not match stage 2.
This is done to prevent you from losing your work-in-progress
-changes. To illustrate, suppose you start from what has been
+changes, and mixing your random changes in an unrelated merge
+commit. To illustrate, suppose you start from what has been
commited last to your repository:
----------------
since you pulled from him:
----------------
-$ git-fetch rsync://.... linus
-$ LT=`cat .git/MERGE_HEAD`
+$ git-fetch git://.... linus
+$ LT=`cat .git/FETCH_HEAD`
----------------
Your work tree is still based on your HEAD ($JC), but you have
your work-in-progress changes, and your work tree would be
updated to the result of the merge.
+However, if you have local changes in the working tree that
+would be overwritten by this merge,`git-read-tree` will refuse
+to run to prevent your changes from being lost.
+
+In other words, there is no need to worry about what exists only
+in the working tree. When you have local changes in a part of
+the project that is not involved in the merge, your changes do
+not interfere with the merge, and are kept intact. When they
+*do* interfere, the merge does not even start (`git-read-tree`
+complains loudly and fails without modifying anything). In such
+a case, you can simply continue doing what you were in the
+middle of doing, and when your working tree is ready (i.e. you
+have finished your work-in-progress), attempt the merge again.
+
See Also
--------