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![Nicolas Pitre](/assets/img/avatar_default.png)
We used to refuse leaving a detached HEAD when it wasn't matching an existing ref so not to lose any commit that might have been performed while not on any branch (unless -f was provided). But this protection was completely bogus since it was still possible to move to HEAD^ while still remaining detached but losing the last commit anyway if there was one. Now that we have a proper reflog for HEAD it is best to simply remove that bogus (and admitedly annoying) protection and simply display the last HEAD position instead. If one wants to recover a lost detached state then it can be retrieved from the HEAD reflog. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
273 lines
6.6 KiB
Bash
Executable file
273 lines
6.6 KiB
Bash
Executable file
#!/bin/sh
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USAGE='[-q] [-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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require_work_tree
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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 $old_name 2>/dev/null)
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new=
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new_name=
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force=
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branch=
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newbranch=
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newbranch_log=
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merge=
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quiet=
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LF='
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'
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while [ "$#" != "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 '$newbranch' as a branch name."
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;;
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"-l")
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newbranch_log=1
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;;
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"-f")
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force=1
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;;
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-m)
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merge=1
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;;
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"-q")
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quiet=1
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;;
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--)
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break
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;;
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-*)
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usage
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;;
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*)
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if rev=$(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 "$new^{commit}" >/dev/null 2>&1 ||
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die "Cannot switch branch to a non-commit."
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fi
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fi
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# We are switching branches and checking out trees, so
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# we *NEED* to be at the toplevel.
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cd_to_toplevel
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[ -z "$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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detached=
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detach_warn=
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if test -z "$branch$newbranch" && test "$new" != "$old"
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then
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detached="$new"
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if test -n "$oldbranch" && test -z "$quiet"
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then
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detach_warn="Note: moving to \"$new_name\" which isn't a local branch
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If you want to create a new branch from this checkout, you may do so
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(now or later) by using -b with the checkout command again. Example:
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git checkout -b <new_branch_name>"
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fi
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elif test -z "$oldbranch" && test -z "$quiet"
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then
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echo >&2 "Previous HEAD position was $old"
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fi
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if [ "X$old" = X ]
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then
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if test -z "$quiet"
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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 $new_name."
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fi
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force=1
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fi
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if [ "$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 $new || exit
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eval GITHEAD_$new=${new_name:-${branch:-$new}} &&
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eval GITHEAD_$work=local &&
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export GITHEAD_$new GITHEAD_$work &&
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git merge-recursive $old -- $new $work
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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 && test -z "$quiet"
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then
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git diff-index --name-status "$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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if test -n "$branch"
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then
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GIT_DIR="$GIT_DIR" git-symbolic-ref -m "checkout: moving to $branch" HEAD "refs/heads/$branch"
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if test -z "$quiet"
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then
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echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
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fi
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elif test -n "$detached"
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then
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# NEEDSWORK: we would want a command to detach the HEAD
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# atomically, instead of this handcrafted command sequence.
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# Perhaps:
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# git update-ref --detach HEAD $new
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# or something like that...
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#
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git-rev-parse HEAD >"$GIT_DIR/HEAD.new" &&
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mv "$GIT_DIR/HEAD.new" "$GIT_DIR/HEAD" &&
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git-update-ref -m "checkout: moving to $arg" HEAD "$detached" ||
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die "Cannot detach HEAD"
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if test -n "$detach_warn"
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then
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echo >&2 "$detach_warn"
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fi
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fi
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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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