SYNOPSIS
--------
-'git
-read-tree' (<tree-ish> | [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]])
+'git
read-tree' (<tree-ish> | [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]])
DESCRIPTION
flag. When used with `-m`, the `-u` flag causes it to also update
the files in the work tree with the result of the merge.
-Trivial merges are done by `git-read-tree` itself. Only conflicting paths
-will be in unmerged state when `git-read-tree` returns.
+Trivial merges are done by 'git-read-tree' itself. Only conflicting paths
+will be in unmerged state when 'git-read-tree' returns.
OPTIONS
-------
Show the progress of checking files out.
--trivial::
- Restrict three-way merge by `git-read-tree` to happen
+ Restrict three-way merge by 'git-read-tree' to happen
only if there is no file-level merging required, instead
of resolving merge for trivial cases and leaving
conflicting files unresolved in the index.
--aggressive::
- Usually a three-way merge by `git-read-tree` resolves
+ Usually a three-way merge by 'git-read-tree' resolves
the merge for really trivial cases and leaves other
cases unresolved in the index, so that Porcelains can
implement different merge policies. This flag makes the
Merging
-------
-If `-m` is specified, `git-read-tree` can perform 3 kinds of
+If `-m` is specified, 'git-read-tree' can perform 3 kinds of
merge, a single tree merge if only 1 tree is given, a
fast-forward merge with 2 trees, or a 3-way merge if 3 trees are
provided.
Single Tree Merge
~~~~~~~~~~~~~~~~~
-If only 1 tree is specified, git-read-tree operates as if the user did not
+If only 1 tree is specified, 'git-read-tree' operates as if the user did not
specify `-m`, except that if the original index has an entry for a
given pathname, and the contents of the path matches with the tree
being read, the stat info from the index is used. (In other words, the
index's stat()s take precedence over the merged tree's).
-That means that if you do a `git-read-tree -m <newtree>` followed by a
-`git-checkout-index -f -u -a`, the `git-checkout-index` only checks out
+That means that if you do a `git read-tree -m <newtree>` followed by a
+`git checkout-index -f -u -a`, the 'git-checkout-index' only checks out
the stuff that really changed.
-This is used to avoid unnecessary false hits when `git-diff-files` is
-run after `git-read-tree`.
+This is used to avoid unnecessary false hits when 'git-diff-files' is
+run after 'git-read-tree'.
Two Tree Merge
~~~~~~~~~~~~~~
-Typically, this is invoked as `git-read-tree -m $H $M`, where $H
+Typically, this is invoked as `git read-tree -m $H $M`, where $H
is the head commit of the current repository, and $M is the head
of a foreign tree, which is simply ahead of $H (i.e. we are in a
fast forward situation).
-When two trees are specified, the user is telling git-read-tree
+When two trees are specified, the user is telling 'git-read-tree'
the following:
1. The current index and work tree is derived from $H, but
2. The user wants to fast-forward to $M.
-In this case, the `git-read-tree -m $H $M` command makes sure
+In this case, the `git read-tree -m $H $M` command makes sure
that no local change is lost as the result of this "merge".
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
------------------
In all "keep index" cases, the index entry stays as in the
original index file. If the entry were not up to date,
-git-read-tree keeps the copy in the work tree intact when
+'git-read-tree' keeps the copy in the work tree intact when
operating under the -u flag.
-When this form of git-read-tree returns successfully, you can
+When this form of 'git-read-tree' returns successfully, you can
see what "local changes" you made are carried forward by running
-`git-diff-index --cached $M`. Note that this does not
-necessarily match `git-diff-index --cached $H` would have
+`git diff-index --cached $M`. Note that this does not
+necessarily match `git diff-index --cached $H` would have
produced before such a two tree merge. This is because of cases
18 and 19 --- if you already had the changes in $M (e.g. maybe
-you picked it up via e-mail in a patch form), `git-diff-index
+you picked it up via e-mail in a patch form), `git diff-index
--cached $H` would have told you about the change before this
-merge, but it would not show in `git-diff-index --cached $M`
+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 switching 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 $M are the same.
3-Way Merge
~~~~~~~~~~~
Each "index" entry has two bits worth of "stage" state. stage 0 is the
normal one, and is the only one you'd see in any kind of normal use.
-However, when you do `git-read-tree` with three trees, the "stage"
+However, when you do 'git-read-tree' with three trees, the "stage"
starts out at 1.
This means that you can do
----------------
-$ git-read-tree -m <tree1> <tree2> <tree3>
+$ git read-tree -m <tree1> <tree2> <tree3>
----------------
and you will end up with an index with all of the <tree1> entries in
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
+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 1 and stage 3 are the same and stage 2 is different take
stage 2 (we did something while they did nothing)
-The `git-write-tree` command refuses to write a nonsensical tree, and it
+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
stage 0.
populated. Here is an outline of how the algorithm works:
- if a file exists in identical format in all three trees, it will
- automatically collapse to "merged" state by git-read-tree.
+ automatically collapse to "merged" state by 'git-read-tree'.
- a file that has _any_ difference what-so-ever in the three trees
will stay as separate entries in the index. It's up to "porcelain
matching "stage1" entry if it exists too. .. all the normal
trivial rules ..
-You would normally use `git-merge-index` with supplied
-`git-merge-one-file` to do this last step. The script updates
+You would normally use 'git-merge-index' with supplied
+'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.
committed last to your repository:
----------------
-$ JC=`git-rev-parse --verify "HEAD^0"`
-$ git-checkout-index -f -u -a $JC
+$ JC=`git rev-parse --verify "HEAD^0"`
+$ git checkout-index -f -u -a $JC
----------------
-You do random edits, without running git-update-index. And then
+You do random edits, without running 'git-update-index'. And then
you notice that the tip of your "upstream" tree has advanced
since you pulled from him:
----------------
-$ git-fetch git://.... linus
+$ git fetch git://.... linus
$ LT=`cat .git/FETCH_HEAD`
----------------
then does the right thing. So with the following sequence:
----------------
-$ git-read-tree -m -u `git-merge-base $JC $LT` $JC $LT
-$ git-merge-index git-merge-one-file -a
+$ git read-tree -m -u `git merge-base $JC $LT` $JC $LT
+$ git merge-index git-merge-one-file -a
$ echo "Merge with Linus" | \
- git-commit-tree `git-write-tree` -p $JC -p $LT
+ git commit-tree `git write-tree` -p $JC -p $LT
----------------
what you would commit is a pure merge between $JC and $LT without
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
+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`
+*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
+SEE ALSO
--------
linkgit:git-write-tree[1]; linkgit:git-ls-files[1];
linkgit:gitignore[5]
GIT
---
-Part of the linkgit:git[7] suite
+Part of the linkgit:git[1] suite