Teach git list-objects logic not to follow gitlinks
[gitweb.git] / git-checkout.sh
index 3bbd1117739b02572aece86030bb9f02f3110d34..deb0a9a3c733ed889158d05b7cae4d174917553d 100755 (executable)
@@ -1,14 +1,24 @@
 #!/bin/sh
 
-USAGE='[-f] [-b <new_branch>] [<branch>] [<paths>...]'
+USAGE='[-q] [-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
 SUBDIRECTORY_OK=Sometimes
 . git-sh-setup
+require_work_tree
 
-old=$(git-rev-parse HEAD)
+old_name=HEAD
+old=$(git-rev-parse --verify $old_name 2>/dev/null)
+oldbranch=$(git-symbolic-ref $old_name 2>/dev/null)
 new=
+new_name=
 force=
 branch=
+track=
 newbranch=
+newbranch_log=
+merge=
+quiet=
+LF='
+'
 while [ "$#" != "0" ]; do
     arg="$1"
     shift
@@ -18,14 +28,26 @@ while [ "$#" != "0" ]; do
                shift
                [ -z "$newbranch" ] &&
                        die "git checkout: -b needs a branch name"
-               [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
+               git-show-ref --verify --quiet -- "refs/heads/$newbranch" &&
                        die "git checkout: branch $newbranch already exists"
                git-check-ref-format "heads/$newbranch" ||
-                       die "we do not like '$newbranch' as a branch name."
+                       die "git checkout: we do not like '$newbranch' as a branch name."
+               ;;
+       "-l")
+               newbranch_log=-l
+               ;;
+       "--track"|"--no-track")
+               track="$arg"
                ;;
        "-f")
                force=1
                ;;
+       -m)
+               merge=1
+               ;;
+       "-q")
+               quiet=1
+               ;;
        --)
                break
                ;;
@@ -40,25 +62,43 @@ while [ "$#" != "0" ]; do
                                exit 1
                        fi
                        new="$rev"
-                       if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
+                       new_name="$arg"
+                       if git-show-ref --verify --quiet -- "refs/heads/$arg"
+                       then
                                branch="$arg"
                        fi
                elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
                then
                        # checking out selected paths from a tree-ish.
                        new="$rev"
+                       new_name="$arg^{tree}"
                        branch=
                else
                        new=
+                       new_name=
                        branch=
                        set x "$arg" "$@"
                        shift
                fi
+               case "$1" in
+               --)
+                       shift ;;
+               esac
                break
                ;;
     esac
 done
 
+case "$newbranch,$track" in
+,--*)
+       die "git checkout: --track and --no-track require -b"
+esac
+
+case "$force$merge" in
+11)
+       die "git checkout: -f and -m are incompatible"
+esac
+
 # The behaviour of the command with and without explicit path
 # parameters is quite different.
 #
@@ -71,9 +111,15 @@ done
 
 if test "$#" -ge 1
 then
-       if test '' != "$newbranch$force"
+       hint=
+       if test "$#" -eq 1
+       then
+               hint="
+Did you intend to checkout '$@' which can not be resolved as commit?"
+       fi
+       if test '' != "$newbranch$force$merge"
        then
-               die "updating paths and switching branches or forcing are incompatible."
+               die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
        fi
        if test '' != "$new"
        then
@@ -83,7 +129,11 @@ then
                git-ls-tree --full-name -r "$new" "$@" |
                git-update-index --index-info || exit $?
        fi
-       git-checkout-index -f -u -- "$@"
+
+       # Make sure the request is about existing paths.
+       git-ls-files --error-unmatch -- "$@" >/dev/null || exit
+       git-ls-files -- "$@" |
+       git-checkout-index -f -u --stdin
        exit $?
 else
        # Make sure we did not fall back on $arg^{tree} codepath
@@ -98,30 +148,99 @@ fi
 
 # We are switching branches and checking out trees, so
 # we *NEED* to be at the toplevel.
-cdup=$(git-rev-parse --show-cdup)
-if test ! -z "$cdup"
-then
-       cd "$cdup"
-fi
+cd_to_toplevel
 
-[ -z "$new" ] && new=$old
+[ -z "$new" ] && new=$old && new_name="$old_name"
 
-# If we don't have an old branch that we're switching to,
+# If we don't have an existing branch that we're switching to,
 # and we don't have a new branch name for the target we
-# are switching to, then we'd better just be checking out
-# what we already had
+# are switching to, then we are detaching our HEAD from any
+# branch.  However, if "git checkout HEAD" detaches the HEAD
+# from the current branch, even though that may be logically
+# correct, it feels somewhat funny.  More importantly, we do not
+# want "git checkout" nor "git checkout -f" to detach HEAD.
+
+detached=
+detach_warn=
 
-[ -z "$branch$newbranch" ] &&
-       [ "$new" != "$old" ] &&
-       die "git checkout: you need to specify a new branch name"
+describe_detached_head () {
+       test -n "$quiet" || {
+               printf >&2 "$1 "
+               GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2"
+       }
+}
+
+if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
+then
+       detached="$new"
+       if test -n "$oldbranch" && test -z "$quiet"
+       then
+               detach_warn="Note: moving to \"$new_name\" which isn't a local branch
+If you want to create a new branch from this checkout, you may do so
+(now or later) by using -b with the checkout command again. Example:
+  git checkout -b <new_branch_name>"
+       fi
+elif test -z "$oldbranch" && test "$new" != "$old"
+then
+       describe_detached_head 'Previous HEAD position was' "$old"
+fi
+
+if [ "X$old" = X ]
+then
+       if test -z "$quiet"
+       then
+               echo >&2 "warning: You appear to be on a branch yet to be born."
+               echo >&2 "warning: Forcing checkout of $new_name."
+       fi
+       force=1
+fi
 
 if [ "$force" ]
 then
-    git-read-tree --reset $new &&
-       git-checkout-index -q -f -u -a
+    git-read-tree --reset -u $new
 else
     git-update-index --refresh >/dev/null
-    git-read-tree -m -u $old $new
+    merge_error=$(git-read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
+       case "$merge" in
+       '')
+               echo >&2 "$merge_error"
+               exit 1 ;;
+       esac
+
+       # Match the index to the working tree, and do a three-way.
+       git diff-files --name-only | git update-index --remove --stdin &&
+       work=`git write-tree` &&
+       git read-tree --reset -u $new || exit
+
+       eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
+       eval GITHEAD_$work=local &&
+       export GITHEAD_$new GITHEAD_$work &&
+       git merge-recursive $old -- $new $work
+
+       # Do not register the cleanly merged paths in the index yet.
+       # this is not a real merge before committing, but just carrying
+       # the working tree changes along.
+       unmerged=`git ls-files -u`
+       git read-tree --reset $new
+       case "$unmerged" in
+       '')     ;;
+       *)
+               (
+                       z40=0000000000000000000000000000000000000000
+                       echo "$unmerged" |
+                       sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
+                       echo "$unmerged"
+               ) | git update-index --index-info
+               ;;
+       esac
+       exit 0
+    )
+    saved_err=$?
+    if test "$saved_err" = 0 && test -z "$quiet"
+    then
+       git diff-index --name-status "$new"
+    fi
+    (exit $saved_err)
 fi
 
 # 
@@ -132,13 +251,39 @@ fi
 #
 if [ "$?" -eq 0 ]; then
        if [ "$newbranch" ]; then
-               leading=`expr "refs/heads/$newbranch" : '\(.*\)/'` &&
-               mkdir -p "$GIT_DIR/$leading" &&
-               echo $new >"$GIT_DIR/refs/heads/$newbranch" || exit
+               git-branch $track $newbranch_log "$newbranch" "$new_name" || exit
                branch="$newbranch"
        fi
-       [ "$branch" ] &&
-       GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
+       if test -n "$branch"
+       then
+               GIT_DIR="$GIT_DIR" git-symbolic-ref -m "checkout: moving to $branch" HEAD "refs/heads/$branch"
+               if test -n "$quiet"
+               then
+                       true    # nothing
+               elif test "refs/heads/$branch" = "$oldbranch"
+               then
+                       echo >&2 "Already on branch \"$branch\""
+               else
+                       echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
+               fi
+       elif test -n "$detached"
+       then
+               # NEEDSWORK: we would want a command to detach the HEAD
+               # atomically, instead of this handcrafted command sequence.
+               # Perhaps:
+               #       git update-ref --detach HEAD $new
+               # or something like that...
+               #
+               git-rev-parse HEAD >"$GIT_DIR/HEAD.new" &&
+               mv "$GIT_DIR/HEAD.new" "$GIT_DIR/HEAD" &&
+               git-update-ref -m "checkout: moving to $arg" HEAD "$detached" ||
+                       die "Cannot detach HEAD"
+               if test -n "$detach_warn"
+               then
+                       echo >&2 "$detach_warn"
+               fi
+               describe_detached_head 'HEAD is now at' HEAD
+       fi
        rm -f "$GIT_DIR/MERGE_HEAD"
 else
        exit 1