git-checkout.sh

   1 #!/bin/sh
   2
   3 OPTIONS_KEEPDASHDASH=t
   4 OPTIONS_SPEC="\
   5 git-checkout [options] [<branch>] [<paths>...]
   6 --
   7 b=          create a new branch started at <branch>
   8 l           create the new branch's reflog
   9 track       arrange that the new branch tracks the remote branch
  10 f           proceed even if the index or working tree is not HEAD
  11 m           merge local modifications into the new branch
  12 q,quiet     be quiet
  13 "
  14 SUBDIRECTORY_OK=Sometimes
  15 . git-sh-setup
  16 require_work_tree
  17
  18 old_name=HEAD
  19 old=$(git rev-parse --verify $old_name 2>/dev/null)
  20 oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
  21 new=
  22 new_name=
  23 force=
  24 branch=
  25 track=
  26 newbranch=
  27 newbranch_log=
  28 merge=
  29 quiet=
  30 v=-v
  31 LF='
  32 '
  33
  34 while test $# != 0; do
  35         case "$1" in
  36         -b)
  37                 shift
  38                 newbranch="$1"
  39                 [ -z "$newbranch" ] &&
  40                         die "git checkout: -b needs a branch name"
  41                 git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
  42                         die "git checkout: branch $newbranch already exists"
  43                 git check-ref-format "heads/$newbranch" ||
  44                         die "git checkout: we do not like '$newbranch' as a branch name."
  45                 ;;
  46         -l)
  47                 newbranch_log=-l
  48                 ;;
  49         --track|--no-track)
  50                 track="$1"
  51                 ;;
  52         -f)
  53                 force=1
  54                 ;;
  55         -m)
  56                 merge=1
  57                 ;;
  58         -q|--quiet)
  59                 quiet=1
  60                 v=
  61                 ;;
  62         --)
  63                 shift
  64                 break
  65                 ;;
  66         *)
  67                 usage
  68                 ;;
  69         esac
  70         shift
  71 done
  72
  73 arg="$1"
  74 if rev=$(git rev-parse --verify "$arg^0" 2>/dev/null)
  75 then
  76         [ -z "$rev" ] && die "unknown flag $arg"
  77         new_name="$arg"
  78         if git show-ref --verify --quiet -- "refs/heads/$arg"
  79         then
  80                 rev=$(git rev-parse --verify "refs/heads/$arg^0")
  81                 branch="$arg"
  82         fi
  83         new="$rev"
  84         shift
  85 elif rev=$(git rev-parse --verify "$arg^{tree}" 2>/dev/null)
  86 then
  87         # checking out selected paths from a tree-ish.
  88         new="$rev"
  89         new_name="$arg^{tree}"
  90         shift
  91 fi
  92 [ "$1" = "--" ] && shift
  93
  94 case "$newbranch,$track" in
  95 ,--*)
  96         die "git checkout: --track and --no-track require -b"
  97 esac
  98
  99 case "$force$merge" in
 100 11)
 101         die "git checkout: -f and -m are incompatible"
 102 esac
 103
 104 # The behaviour of the command with and without explicit path
 105 # parameters is quite different.
 106 #
 107 # Without paths, we are checking out everything in the work tree,
 108 # possibly switching branches.  This is the traditional behaviour.
 109 #
 110 # With paths, we are _never_ switching branch, but checking out
 111 # the named paths from either index (when no rev is given),
 112 # or the named tree-ish (when rev is given).
 113
 114 if test "$#" -ge 1
 115 then
 116         hint=
 117         if test "$#" -eq 1
 118         then
 119                 hint="
 120 Did you intend to checkout '$@' which can not be resolved as commit?"
 121         fi
 122         if test '' != "$newbranch$force$merge"
 123         then
 124                 die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
 125         fi
 126         if test '' != "$new"
 127         then
 128                 # from a specific tree-ish; note that this is for
 129                 # rescuing paths and is never meant to remove what
 130                 # is not in the named tree-ish.
 131                 git ls-tree --full-name -r "$new" "$@" |
 132                 git update-index --index-info || exit $?
 133         fi
 134
 135         # Make sure the request is about existing paths.
 136         git ls-files --full-name --error-unmatch -- "$@" >/dev/null || exit
 137         git ls-files --full-name -- "$@" |
 138                 (cd_to_toplevel && git checkout-index -f -u --stdin)
 139
 140         # Run a post-checkout hook -- the HEAD does not change so the
 141         # current HEAD is passed in for both args
 142         if test -x "$GIT_DIR"/hooks/post-checkout; then
 143             "$GIT_DIR"/hooks/post-checkout $old $old 0
 144         fi
 145
 146         exit $?
 147 else
 148         # Make sure we did not fall back on $arg^{tree} codepath
 149         # since we are not checking out from an arbitrary tree-ish,
 150         # but switching branches.
 151         if test '' != "$new"
 152         then
 153                 git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
 154                 die "Cannot switch branch to a non-commit."
 155         fi
 156 fi
 157
 158 # We are switching branches and checking out trees, so
 159 # we *NEED* to be at the toplevel.
 160 cd_to_toplevel
 161
 162 [ -z "$new" ] && new=$old && new_name="$old_name"
 163
 164 # If we don't have an existing branch that we're switching to,
 165 # and we don't have a new branch name for the target we
 166 # are switching to, then we are detaching our HEAD from any
 167 # branch.  However, if "git checkout HEAD" detaches the HEAD
 168 # from the current branch, even though that may be logically
 169 # correct, it feels somewhat funny.  More importantly, we do not
 170 # want "git checkout" nor "git checkout -f" to detach HEAD.
 171
 172 detached=
 173 detach_warn=
 174
 175 describe_detached_head () {
 176         test -n "$quiet" || {
 177                 printf >&2 "$1 "
 178                 GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
 179         }
 180 }
 181
 182 if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
 183 then
 184         detached="$new"
 185         if test -n "$oldbranch" && test -z "$quiet"
 186         then
 187                 detach_warn="Note: moving to \"$new_name\" which isn't a local branch
 188 If you want to create a new branch from this checkout, you may do so
 189 (now or later) by using -b with the checkout command again. Example:
 190   git checkout -b <new_branch_name>"
 191         fi
 192 elif test -z "$oldbranch" && test "$new" != "$old"
 193 then
 194         describe_detached_head 'Previous HEAD position was' "$old"
 195 fi
 196
 197 if [ "X$old" = X ]
 198 then
 199         if test -z "$quiet"
 200         then
 201                 echo >&2 "warning: You appear to be on a branch yet to be born."
 202                 echo >&2 "warning: Forcing checkout of $new_name."
 203         fi
 204         force=1
 205 fi
 206
 207 if [ "$force" ]
 208 then
 209     git read-tree $v --reset -u $new
 210 else
 211     git update-index --refresh >/dev/null
 212     merge_error=$(git read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
 213         case "$merge" in
 214         '')
 215                 echo >&2 "$merge_error"
 216                 exit 1 ;;
 217         esac
 218
 219         # Match the index to the working tree, and do a three-way.
 220         git diff-files --name-only | git update-index --remove --stdin &&
 221         work=`git write-tree` &&
 222         git read-tree $v --reset -u $new || exit
 223
 224         eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
 225         eval GITHEAD_$work=local &&
 226         export GITHEAD_$new GITHEAD_$work &&
 227         git merge-recursive $old -- $new $work
 228
 229         # Do not register the cleanly merged paths in the index yet.
 230         # this is not a real merge before committing, but just carrying
 231         # the working tree changes along.
 232         unmerged=`git ls-files -u`
 233         git read-tree $v --reset $new
 234         case "$unmerged" in
 235         '')     ;;
 236         *)
 237                 (
 238                         z40=0000000000000000000000000000000000000000
 239                         echo "$unmerged" |
 240                         sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
 241                         echo "$unmerged"
 242                 ) | git update-index --index-info
 243                 ;;
 244         esac
 245         exit 0
 246     )
 247     saved_err=$?
 248     if test "$saved_err" = 0 && test -z "$quiet"
 249     then
 250         git diff-index --name-status "$new"
 251     fi
 252     (exit $saved_err)
 253 fi
 254
 255 #
 256 # Switch the HEAD pointer to the new branch if we
 257 # checked out a branch head, and remove any potential
 258 # old MERGE_HEAD's (subsequent commits will clearly not
 259 # be based on them, since we re-set the index)
 260 #
 261 if [ "$?" -eq 0 ]; then
 262         if [ "$newbranch" ]; then
 263                 git branch $track $newbranch_log "$newbranch" "$new_name" || exit
 264                 branch="$newbranch"
 265         fi
 266         if test -n "$branch"
 267         then
 268                 old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
 269                 GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch"
 270                 if test -n "$quiet"
 271                 then
 272                         true    # nothing
 273                 elif test "refs/heads/$branch" = "$oldbranch"
 274                 then
 275                         echo >&2 "Already on branch \"$branch\""
 276                 else
 277                         echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
 278                 fi
 279         elif test -n "$detached"
 280         then
 281                 old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
 282                 git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $arg" HEAD "$detached" ||
 283                         die "Cannot detach HEAD"
 284                 if test -n "$detach_warn"
 285                 then
 286                         echo >&2 "$detach_warn"
 287                 fi
 288                 describe_detached_head 'HEAD is now at' HEAD
 289         fi
 290         rm -f "$GIT_DIR/MERGE_HEAD"
 291 else
 292         exit 1
 293 fi
 294
 295 # Run a post-checkout hook
 296 if test -x "$GIT_DIR"/hooks/post-checkout; then
 297         "$GIT_DIR"/hooks/post-checkout $old $new 1
 298 fi