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