mirror of
https://github.com/git/git.git
synced 2024-11-20 14:24:12 +01:00
75b364dfe2
Checking for reachability from refs does not help much if the state we are currently on is somewhere in the middle. We will lose where we were. So this makes sureh that HEAD is something directly pointed at by one of the existing refs (most likely a tag for a user who has been "sightseeing"). Signed-off-by: Junio C Hamano <junkio@cox.net>
267 lines
6.6 KiB
Bash
Executable File
267 lines
6.6 KiB
Bash
Executable File
#!/bin/sh
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USAGE='[-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
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SUBDIRECTORY_OK=Sometimes
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. git-sh-setup
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old_name=HEAD
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old=$(git-rev-parse --verify $old_name 2>/dev/null)
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oldbranch=$(git-symbolic-ref $old_name 2>/dev/null)
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new=
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new_name=
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force=
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branch=
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newbranch=
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newbranch_log=
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merge=
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LF='
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'
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while [ "$#" != "0" ]; do
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arg="$1"
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shift
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case "$arg" in
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"-b")
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newbranch="$1"
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shift
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[ -z "$newbranch" ] &&
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die "git checkout: -b needs a branch name"
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git-show-ref --verify --quiet -- "refs/heads/$newbranch" &&
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die "git checkout: branch $newbranch already exists"
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git-check-ref-format "heads/$newbranch" ||
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die "git checkout: we do not like '$newbranch' as a branch name."
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;;
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"-l")
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newbranch_log=1
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;;
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"-f")
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force=1
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;;
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-m)
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merge=1
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;;
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--)
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break
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;;
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-*)
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usage
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;;
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*)
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if rev=$(git-rev-parse --verify "$arg^0" 2>/dev/null)
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then
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if [ -z "$rev" ]; then
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echo "unknown flag $arg"
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exit 1
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fi
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new="$rev"
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new_name="$arg"
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if git-show-ref --verify --quiet -- "refs/heads/$arg"
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then
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branch="$arg"
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fi
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elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
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then
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# checking out selected paths from a tree-ish.
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new="$rev"
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new_name="$arg^{tree}"
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branch=
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else
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new=
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new_name=
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branch=
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set x "$arg" "$@"
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shift
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fi
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case "$1" in
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--)
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shift ;;
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esac
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break
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;;
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esac
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done
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case "$force$merge" in
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11)
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die "git checkout: -f and -m are incompatible"
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esac
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# The behaviour of the command with and without explicit path
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# parameters is quite different.
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#
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# Without paths, we are checking out everything in the work tree,
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# possibly switching branches. This is the traditional behaviour.
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#
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# With paths, we are _never_ switching branch, but checking out
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# the named paths from either index (when no rev is given),
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# or the named tree-ish (when rev is given).
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if test "$#" -ge 1
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then
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hint=
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if test "$#" -eq 1
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then
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hint="
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Did you intend to checkout '$@' which can not be resolved as commit?"
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fi
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if test '' != "$newbranch$force$merge"
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then
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die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
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fi
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if test '' != "$new"
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then
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# from a specific tree-ish; note that this is for
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# rescuing paths and is never meant to remove what
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# is not in the named tree-ish.
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git-ls-tree --full-name -r "$new" "$@" |
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git-update-index --index-info || exit $?
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fi
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# Make sure the request is about existing paths.
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git-ls-files --error-unmatch -- "$@" >/dev/null || exit
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git-ls-files -- "$@" |
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git-checkout-index -f -u --stdin
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exit $?
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else
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# Make sure we did not fall back on $arg^{tree} codepath
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# since we are not checking out from an arbitrary tree-ish,
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# but switching branches.
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if test '' != "$new"
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then
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git-rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
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die "Cannot switch branch to a non-commit."
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fi
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fi
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# We are switching branches and checking out trees, so
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# we *NEED* to be at the toplevel.
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cdup=$(git-rev-parse --show-cdup)
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if test ! -z "$cdup"
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then
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cd "$cdup"
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fi
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[ -z "$new" ] && new=$old && new_name="$old_name"
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# If we don't have an existing branch that we're switching to,
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# and we don't have a new branch name for the target we
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# are switching to, then we are detaching our HEAD from any
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# branch. However, if "git checkout HEAD" detaches the HEAD
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# from the current branch, even though that may be logically
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# correct, it feels somewhat funny. More importantly, we do not
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# want "git checkout" nor "git checkout -f" to detach HEAD.
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if test -z "$branch$newbranch" && test "$new" != "$old"
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then
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# NEEDSWORK: we would want to have a command here
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# that allows us to detach the HEAD atomically. Perhaps
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# something like "git update-ref --detach HEAD $new"
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echo "$new" >"$GIT_DIR/HEAD.new" &&
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mv "$GIT_DIR/HEAD.new" "$GIT_DIR/HEAD" || die "Cannot detach HEAD"
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if test -n "$oldbranch"
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then
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echo >&2 "warning: you are not on ANY branch anymore.
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If you meant to create a new branch from the commit, you need -b to
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associate a new branch with the wanted checkout. Example:
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git checkout -b <new_branch_name> $arg
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"
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fi
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elif test -z "$oldbranch" && test -n "$branch"
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then
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# Coming back...
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if test -z "$force"
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then
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git show-ref -d -s | grep "$old" >/dev/null || {
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echo >&2 \
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"You are not on any branch and switching to branch '$new_name'
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may lose your changes. At this point, you can do one of two things:
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(1) Decide it is Ok and say 'git checkout -f $new_name';
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(2) Start a new branch from the current commit, by saying
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'git checkout -b <branch-name>'.
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Leaving your HEAD detached; not switching to branch '$new_name'."
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exit 1;
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}
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fi
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fi
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if [ "X$old" = X ]
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then
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echo >&2 "warning: You appear to be on a branch yet to be born."
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echo >&2 "warning: Forcing checkout of $new_name."
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force=1
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fi
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if [ "$force" ]
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then
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git-read-tree --reset -u $new
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else
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git-update-index --refresh >/dev/null
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merge_error=$(git-read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
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case "$merge" in
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'')
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echo >&2 "$merge_error"
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exit 1 ;;
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esac
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# Match the index to the working tree, and do a three-way.
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git diff-files --name-only | git update-index --remove --stdin &&
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work=`git write-tree` &&
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git read-tree --reset -u $new &&
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git read-tree -m -u --aggressive --exclude-per-directory=.gitignore $old $new $work ||
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exit
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if result=`git write-tree 2>/dev/null`
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then
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echo >&2 "Trivially automerged."
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else
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git merge-index -o git-merge-one-file -a
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fi
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# Do not register the cleanly merged paths in the index yet.
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# this is not a real merge before committing, but just carrying
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# the working tree changes along.
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unmerged=`git ls-files -u`
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git read-tree --reset $new
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case "$unmerged" in
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'') ;;
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*)
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(
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z40=0000000000000000000000000000000000000000
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echo "$unmerged" |
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sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
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echo "$unmerged"
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) | git update-index --index-info
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;;
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esac
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exit 0
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)
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saved_err=$?
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if test "$saved_err" = 0
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then
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test "$new" = "$old" || git diff-index --name-status "$new"
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fi
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(exit $saved_err)
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fi
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#
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# Switch the HEAD pointer to the new branch if we
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# checked out a branch head, and remove any potential
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# old MERGE_HEAD's (subsequent commits will clearly not
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# be based on them, since we re-set the index)
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#
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if [ "$?" -eq 0 ]; then
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if [ "$newbranch" ]; then
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if [ "$newbranch_log" ]; then
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mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$newbranch")
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touch "$GIT_DIR/logs/refs/heads/$newbranch"
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fi
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git-update-ref -m "checkout: Created from $new_name" "refs/heads/$newbranch" $new || exit
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branch="$newbranch"
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fi
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[ "$branch" ] &&
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GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
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rm -f "$GIT_DIR/MERGE_HEAD"
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else
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exit 1
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fi
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