cherry-pick: Suggest a better method to retain authorship

diff --git a/git-checkout.sh b/git-checkout.sh
index 0bae86e325eba0326e29c73ffbaafa0e8eda897f..14835a4aa982af88d758ea014afacf7b2fb1bb1e 100755 (executable)
--- a/git-checkout.sh
+++ b/git-checkout.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-USAGE='[-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
+USAGE='[-q] [-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
 SUBDIRECTORY_OK=Sometimes
 . git-sh-setup
 require_work_tree
@@ -15,6 +15,7 @@ branch=
 newbranch=
 newbranch_log=
 merge=
+quiet=
 LF='
 '
 while [ "$#" != "0" ]; do
@@ -40,6 +41,9 @@ while [ "$#" != "0" ]; do
        -m)
                merge=1
                ;;
+       "-q")
+               quiet=1
+               ;;
        --)
                break
                ;;
@@ -153,35 +157,25 @@ detach_warn=
 if test -z "$branch$newbranch" && test "$new" != "$old"
 then
        detached="$new"
-       if test -n "$oldbranch"
+       if test -n "$oldbranch" && test -z "$quiet"
        then
-               detach_warn="Note: you are not on ANY branch anymore.
+               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 -n "$branch"
+elif test -z "$oldbranch" && test -z "$quiet"
 then
-       # Coming back...
-       if test -z "$force"
-       then
-               git show-ref -d -s | grep "$old" >/dev/null || {
-                       echo >&2 \
-"You are not on any branch and switching to branch '$new_name'
-may lose your changes.  At this point, you can do one of two things:
- (1) Decide it is Ok and say 'git checkout -f $new_name';
- (2) Start a new branch from the current commit, by saying
-     'git checkout -b <branch-name>'.
-Leaving your HEAD detached; not switching to branch '$new_name'."
-                       exit 1;
-               }
-       fi
+       echo >&2 "Previous HEAD position was $old"
 fi
 
 if [ "X$old" = X ]
 then
-       echo >&2 "warning: You appear to be on a branch yet to be born."
-       echo >&2 "warning: Forcing checkout of $new_name."
+       if test -z "$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
 
@@ -226,9 +220,9 @@ else
        exit 0
     )
     saved_err=$?
-    if test "$saved_err" = 0
+    if test "$saved_err" = 0 && test -z "$quiet"
     then
-       test "$new" = "$old" || git diff-index --name-status "$new"
+       git diff-index --name-status "$new"
     fi
     (exit $saved_err)
 fi
@@ -250,7 +244,11 @@ if [ "$?" -eq 0 ]; then
        fi
        if test -n "$branch"
        then
-               GIT_DIR="$GIT_DIR" git-symbolic-ref HEAD "refs/heads/$branch"
+               GIT_DIR="$GIT_DIR" git-symbolic-ref -m "checkout: moving to $branch" HEAD "refs/heads/$branch"
+               if test -z "$quiet"
+               then
+                       echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
+               fi
        elif test -n "$detached"
        then
                # NEEDSWORK: we would want a command to detach the HEAD
@@ -259,8 +257,9 @@ if [ "$?" -eq 0 ]; then
                #       git update-ref --detach HEAD $new
                # or something like that...
                #
-               echo "$detached" >"$GIT_DIR/HEAD.new" &&
-               mv "$GIT_DIR/HEAD.new" "$GIT_DIR/HEAD" ||
+               git-rev-parse HEAD >"$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