filter-branch: use --simplify-merges

Use rev-list --simplify-merges everywhere.  This changes the behaviour
of --subdirectory-filter in cases such as

O -- A -\
\       \
\- B -- M

where A and B bring the same changes to the subdirectory: It now keeps
both sides of the merge.  Previously, the history would have been
simplified to 'O -- A'.  Merges of unrelated side histories that never
touch the subdirectory are still removed.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index a140337e3558888f625f9656f7c21ea25f64d8be..2688254af399ddc452b120734d41b41292b0ed69 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 " ")
 
@@ -326,7 +326,8 @@ then
        do
                sha1=$(git rev-parse "$ref"^0)
                test -f "$workdir"/../map/$sha1 && continue
-               ancestor=$(git rev-list -1 $ref -- "$filter_subdir")
+               ancestor=$(git rev-list --simplify-merges -1 \
+                               $ref -- "$filter_subdir")
                test "$ancestor" && echo $(map $ancestor) >> "$workdir"/../map/$sha1
        done < "$tempdir"/heads
 fi