Documentation: clarify which parameters are optional to git-cherry

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index a324cf0596ee0f05831190ce724fe9134bc7f568..c106f45af73446d26630030f77107efa520aa296 100755 (executable)
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -232,11 +232,11 @@ mkdir ../map || die "Could not create map/ directory"
 case "$filter_subdir" in
 "")
        git rev-list --reverse --topo-order --default HEAD \
-               --parents "$@"
+               --parents --simplify-merges "$@"
        ;;
 *)
        git rev-list --reverse --topo-order --default HEAD \
-               --parents "$@" -- "$filter_subdir"
+               --parents --simplify-merges "$@" -- "$filter_subdir"
 esac > ../revs || die "Could not get the commits"
 commits=$(wc -l <../revs | tr -d " ")
 
@@ -256,7 +256,7 @@ while read commit parents; do
        *)
                # The commit may not have the subdirectory at all
                err=$(git read-tree -i -m $commit:"$filter_subdir" 2>&1) || {
-                       if ! git rev-parse --verify $commit:"$filter_subdir" 2>/dev/null
+                       if ! git rev-parse -q --verify $commit:"$filter_subdir"
                        then
                                rm -f "$GIT_INDEX_FILE"
                        else
@@ -317,24 +317,20 @@ done <../revs
 
 # In case of a subdirectory filter, it is possible that a specified head
 # is not in the set of rewritten commits, because it was pruned by the
-# revision walker.  Fix it by mapping these heads to the next rewritten
-# ancestor(s), i.e. the boundaries in the set of rewritten commits.
+# revision walker.  Fix it by mapping these heads to the unique nearest
+# ancestor that survived the pruning.
 
-# NEEDSWORK: we should sort the unmapped refs topologically first
-while read ref
-do
-       sha1=$(git rev-parse "$ref"^0)
-       test -f "$workdir"/../map/$sha1 && continue
-       # Assign the boundarie(s) in the set of rewritten commits
-       # as the replacement commit(s).
-       # (This would look a bit nicer if --not --stdin worked.)
-       for p in $( (cd "$workdir"/../map; ls | sed "s/^/^/") |
-               git rev-list $ref --boundary --stdin |
-               sed -n "s/^-//p")
+if test "$filter_subdir"
+then
+       while read ref
        do
-               map $p >> "$workdir"/../map/$sha1
-       done
-done < "$tempdir"/heads
+               sha1=$(git rev-parse "$ref"^0)
+               test -f "$workdir"/../map/$sha1 && continue
+               ancestor=$(git rev-list --simplify-merges -1 \
+                               $ref -- "$filter_subdir")
+               test "$ancestor" && echo $(map $ancestor) >> "$workdir"/../map/$sha1
+       done < "$tempdir"/heads
+fi
 
 # Finally update the refs
 
@@ -416,15 +412,17 @@ if [ "$filter_tag_name" ]; then
                echo "$ref -> $new_ref ($sha1 -> $new_sha1)"
 
                if [ "$type" = "tag" ]; then
-                       new_sha1=$(git cat-file tag "$ref" |
+                       new_sha1=$( ( printf 'object %s\ntype commit\ntag %s\n' \
+                                               "$new_sha1" "$new_ref"
+                               git cat-file tag "$ref" |
                                sed -n \
                                    -e "1,/^$/{
-                                         s/^object .*/object $new_sha1/
-                                         s/^type .*/type commit/
-                                         s/^tag .*/tag $new_ref/
+                                         /^object /d
+                                         /^type /d
+                                         /^tag /d
                                        }" \
                                    -e '/^-----BEGIN PGP SIGNATURE-----/q' \
-                                   -e 'p' |
+                                   -e 'p' ) |
                                git mktag) ||
                                die "Could not create new tag object for $ref"
                        if git cat-file tag "$ref" | \