Add a "-u" flag to update the tree as a result of a merge.
Right now this code is way too anal about things, and fails merges it
shouldn't, but let me fix up the different cases and this will allow for
much smoother merging even in the presense of dirty data in the working
tree.
We don't want to overwrite state that we haven't committed yet
when merging, so it's better to make git-read-tree fail than
end up with a merge tree that ends up not having the dirty changes.
Update git-resolve-script to fail cleanly when git-read-tree fails.
During the mailing list discussion on renaming GIT_ environment
variables, people felt that having one environment that lets the
user (or Porcelain) specify both SHA1_FILE_DIRECTORY (now
GIT_OBJECT_DIRECTORY) and GIT_INDEX_FILE for the default layout
would be handy. This change introduces GIT_DIR environment
variable, from which the defaults for GIT_INDEX_FILE and
GIT_OBJECT_DIRECTORY are derived. When GIT_DIR is not defined,
it defaults to ".git". GIT_INDEX_FILE defaults to
"$GIT_DIR/index" and GIT_OBJECT_DIRECTORY defaults to
"$GIT_DIR/objects".
Special thanks for ideas and discussions go to Petr Baudis and
Daniel Barkalow. Bugs are mine ;-)
Signed-off-by: Junio C Hamano <junkio@cox.net>
Separate out the merge resolve from the actual getting of the
data. Also, update the resolve phase to take advantage of the
fact that we don't need to do the commit->tree object lookup
by hand, since all the actors involved happily just act on a
commit object these days.
