Okay, that was a little too aggressive.

Now we only prune out a commit if it has exactly one remaining parent and
that parent's tree is identical to ours.

But I also changed the test to create the initial "-s ours" merge in one
step instead of two, and that merge can be eliminated since one of its
parents doesn't affect the subdir at all, and is thus deleted.

diff --git a/git-subtree.sh b/git-subtree.sh
index 03107e2251c35e0f31e4e29ab9f0fb5515079ced..d42cc1a1643cfd03b797ddc101fdca52a4023026 100755 (executable)
--- a/git-subtree.sh
+++ b/git-subtree.sh
@@ -4,17 +4,21 @@
 #
 # Copyright (C) 2009 Avery Pennarun <apenwarr@gmail.com>
 #
+if [ $# -eq 0 ]; then
+    set -- -h
+fi
 OPTS_SPEC="\
-git subtree split [--rejoin] [--onto rev] <commit...> -- <path>
+git subtree split [options...] <commit...> -- <path>
 git subtree merge 
 
 git subtree does foo and bar!
 --
-h,help   show the help
-q        quiet
-v        verbose
-onto=    existing subtree revision to search for parent
-rejoin   merge the new branch back into HEAD
+h,help        show the help
+q             quiet
+v             verbose
+onto=         try connecting new tree to an existing one
+rejoin        merge the new branch back into HEAD
+ignore-joins  ignore prior --rejoin commits
 "
 eval $(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)
 . git-sh-setup
@@ -24,6 +28,7 @@ quiet=
 command=
 onto=
 rejoin=
+ignore_joins=
 
 debug()
 {
@@ -50,7 +55,11 @@ while [ $# -gt 0 ]; do
        case "$opt" in
                -q) quiet=1 ;;
                --onto) onto="$1"; shift ;;
+               --no-onto) onto= ;;
                --rejoin) rejoin=1 ;;
+               --no-rejoin) rejoin= ;;
+               --ignore-joins) ignore_joins=1 ;;
+               --no-ignore-joins) ignore_joins= ;;
                --) break ;;
        esac
 done
@@ -209,20 +218,25 @@ copy_or_skip()
        newparents="$3"
        assert [ -n "$tree" ]
 
-       p=""
+       identical=
+       p=
        for parent in $newparents; do
                ptree=$(toptree_for_commit $parent) || exit $?
                if [ "$ptree" = "$tree" ]; then
-                       # any identical parent means this commit is unnecessary
-                       echo $parent
-                       return 0
-               elif [ -n "$ptree" ]; then
-                       # an existing, non-identical parent is important
+                       # an identical parent could be used in place of this rev.
+                       identical="$parent"
+               fi
+               if [ -n "$ptree" ]; then
+                       parentmatch="$parentmatch$parent"
                        p="$p -p $parent"
                fi
        done
        
-       copy_commit $rev $tree "$p" || exit $?
+       if [ -n "$identical" -a "$parentmatch" = "$identical" ]; then
+               echo $identical
+       else
+               copy_commit $rev $tree "$p" || exit $?
+       fi
 }
 
 cmd_split()
@@ -241,7 +255,11 @@ cmd_split()
                done
        fi
        
-       unrevs="$(find_existing_splits "$dir" "$revs")"
+       if [ -n "$ignore_joins" ]; then
+               unrevs=
+       else
+               unrevs="$(find_existing_splits "$dir" "$revs")"
+       fi
        
        debug "git rev-list --reverse $revs $unrevs"
        git rev-list --reverse --parents $revs $unrevsx |

diff --git a/test.sh b/test.sh
index a8ed0dbc7d9b927ddb12d7e42c925ce12867a68d..39c4382f0df292b1969e73f6dd52007baf18e536 100755 (executable)
--- a/test.sh
+++ b/test.sh
@@ -35,7 +35,10 @@ git fetch ../subproj sub1
 git branch sub1 FETCH_HEAD
 git read-tree --prefix=subdir FETCH_HEAD
 git checkout subdir
-git commit -m 'initial-subdir-merge'
+tree=$(git write-tree)
+com=$(echo initial-subdir-merge | git commit-tree $tree -p HEAD -p FETCH_HEAD)
+git reset $com
+#git commit -m 'initial-subdir-merge'
 
 git merge -m 'merge -s -ours' -s ours FETCH_HEAD