Use information about prior splits to make sure merges work right.

diff --git a/git-subtree.sh b/git-subtree.sh
index a31b0b2f6a6ebc11e1c21c61a934ddb68d7275da..af1d332e24782b3afb374a46c735235027d38bfd 100755 (executable)
--- a/git-subtree.sh
+++ b/git-subtree.sh
@@ -46,7 +46,6 @@ assert()
 
 while [ $# -gt 0 ]; do
        opt="$1"
-       debug "option: $1"
        shift
        case "$opt" in
                -q) quiet=1 ;;
@@ -108,6 +107,30 @@ cache_set()
        echo "$newrev" >"$cachedir/$oldrev"
 }
 
+find_existing_splits()
+{
+       debug "Looking for prior splits..."
+       dir="$1"
+       revs="$2"
+       git log --grep="^git-subtree-dir: $dir\$" \
+               --pretty=format:'%s%n%n%b%nEND' "$revs" |
+       while read a b junk; do
+               case "$a" in
+                       git-subtree-mainline:) main="$b" ;;
+                       git-subtree-split:) sub="$b" ;;
+                       *)
+                               if [ -n "$main" -a -n "$sub" ]; then
+                                       debug "  Prior: $main -> $sub"
+                                       cache_set $main $sub
+                                       echo "^$main^ ^$sub^"
+                                       main=
+                                       sub=
+                               fi
+                               ;;
+               esac
+       done
+}
+
 copy_commit()
 {
        # We're doing to set some environment vars here, so
@@ -136,10 +159,11 @@ merge_msg()
        latest_old="$2"
        latest_new="$3"
        cat <<-EOF
-               Split changes from '$dir/' into commit '$latest_new'
+               Split '$dir/' into commit '$latest_new'
                
                git-subtree-dir: $dir
-               git-subtree-includes: $latest_old
+               git-subtree-mainline: $latest_old
+               git-subtree-split: $latest_new
        EOF
 }
 
@@ -148,12 +172,20 @@ cmd_split()
        debug "Splitting $dir..."
        cache_setup || exit $?
        
-       git rev-list --reverse --parents $revs -- "$dir" |
+       unrevs="$(find_existing_splits "$dir" "$revs")"
+       
+       git rev-list --reverse --parents $revs $unrevs -- "$dir" |
        while read rev parents; do
+               exists=$(cache_get $rev)
                newparents=$(cache_get $parents)
                debug
                debug "Processing commit: $rev / $newparents"
                
+               if [ -n "$exists" ]; then
+                       debug "  prior: $exists"
+                       continue
+               fi
+               
                git ls-tree $rev -- "$dir" |
                while read mode type tree name; do
                        assert [ "$name" = "$dir" ]