Re: Raw commands to add object to existing tree

On Fri, Aug 21, 2009 at 10:31 PM, D Sundstrom[off-list ref] wrote:

Both the community git manual:
http://book.git-scm.com/7_raw_git.html

and Pro Git book:
http://progit.org/book/ch9-2.html

walk you though low level details of creating objects and trees in git, and
then committing these new trees.

However, they do not show you how to add and commit into existing trees.

Naturally, you can't change an "existing" tree, because any given tree
(identified by its sha-1 hash) can never change.  You presumably want
to create a *new* tree and commit that.

The easiest way I know to do this is to create a new indexfile, fill
it with what you want, and create the tree for that.

(Warning: untested code follows)

export GIT_INDEX_FILE=/tmp/my-temp-index
git read-tree PREVIOUS_COMMIT_OR_TREE_ID
hash=$(git hash-object NEW_FILE)
git update-index --cacheinfo "0644 $hash path/of/file/in/tree"
commitid=$(echo COMMIT MESSAGE | git commit-tree $(git write-tree))
git update-ref refs/heads/BRANCHNAME $commitid PREVIOUS_COMMIT_OR_TREE_ID

Have fun,

Avery