git-svn: add the commit-diff command

diff --git a/git-checkout.sh b/git-checkout.sh
index 3bbd1117739b02572aece86030bb9f02f3110d34..77c25938091b75f51eb3cc5922d67db6333e1e74 100755 (executable)
--- a/git-checkout.sh
+++ b/git-checkout.sh
@@ -1,14 +1,18 @@
 #!/bin/sh
 
-USAGE='[-f] [-b <new_branch>] [<branch>] [<paths>...]'
+USAGE='[-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
 SUBDIRECTORY_OK=Sometimes
 . git-sh-setup
 
 old=$(git-rev-parse HEAD)
+old_name=HEAD
 new=
+new_name=
 force=
 branch=
 newbranch=
+newbranch_log=
+merge=
 while [ "$#" != "0" ]; do
     arg="$1"
     shift
@@ -21,11 +25,17 @@ while [ "$#" != "0" ]; do
                [ -e "$GIT_DIR/refs/heads/$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=1
                ;;
        "-f")
                force=1
                ;;
+       -m)
+               merge=1
+               ;;
        --)
                break
                ;;
@@ -40,6 +50,7 @@ while [ "$#" != "0" ]; do
                                exit 1
                        fi
                        new="$rev"
+                       new_name="$arg^0"
                        if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
                                branch="$arg"
                        fi
@@ -47,9 +58,11 @@ while [ "$#" != "0" ]; do
                then
                        # checking out selected paths from a tree-ish.
                        new="$rev"
+                       new_name="$arg^{tree}"
                        branch=
                else
                        new=
+                       new_name=
                        branch=
                        set x "$arg" "$@"
                        shift
@@ -71,9 +84,15 @@ 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
@@ -104,7 +123,7 @@ then
        cd "$cdup"
 fi
 
-[ -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,
 # and we don't have a new branch name for the target we
@@ -113,15 +132,59 @@ fi
 
 [ -z "$branch$newbranch" ] &&
        [ "$new" != "$old" ] &&
-       die "git checkout: you need to specify a new branch name"
+       die "git checkout: to checkout the requested commit you need to specify 
+              a name for a new branch which is created and switched to"
 
 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 $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 $new &&
+       git checkout-index -f -u -q -a &&
+       git read-tree -m -u --aggressive $old $new $work || exit
+
+       if result=`git write-tree 2>/dev/null`
+       then
+           echo >&2 "Trivially automerged."
+       else
+           git merge-index -o git-merge-one-file -a
+       fi
+
+       # 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
+    then
+       test "$new" = "$old" || git diff-index --name-status "$new"
+    fi
+    (exit $saved_err)
 fi
 
 # 
@@ -132,9 +195,11 @@ fi
 #
 if [ "$?" -eq 0 ]; then
        if [ "$newbranch" ]; then
-               leading=`expr "refs/heads/$newbranch" : '\(.*\)/'` &&
-               mkdir -p "$GIT_DIR/$leading" &&
-               echo $new >"$GIT_DIR/refs/heads/$newbranch" || exit
+               if [ "$newbranch_log" ]; then
+                       mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$newbranch")
+                       touch "$GIT_DIR/logs/refs/heads/$newbranch"
+               fi
+               git-update-ref -m "checkout: Created from $new_name" "refs/heads/$newbranch" $new || exit
                branch="$newbranch"
        fi
        [ "$branch" ] &&