Trim some extra merge commits that don't need to go into the split tree.

...and update test.sh to test for this.

git-subtree.sh

@@ -168,6 +168,7 @@ copy_commit()
 {
 	# We're doing to set some environment vars here, so
 	# do it in a subshell to get rid of them safely later
+	debug copy_commit "{$1}" "{$2}" "{$3}"
 	git log -1 --pretty=format:'%an%n%ae%n%ad%n%cn%n%ce%n%cd%n%s%n%n%b' "$1" |
 	(
 		read GIT_AUTHOR_NAME
@@ -258,19 +259,31 @@ copy_or_skip()
 
 	identical=
 	p=
+	gotparents=
 	for parent in $newparents; do
 		ptree=$(toptree_for_commit $parent) || exit $?
+		[ -z "$ptree" ] && continue
 		if [ "$ptree" = "$tree" ]; then
 			# an identical parent could be used in place of this rev.
 			identical="$parent"
 		fi
-		if [ -n "$ptree" ]; then
-			parentmatch="$parentmatch$parent"
+		
+		# sometimes both old parents map to the same newparent;
+		# eliminate duplicates
+		is_new=1
+		for gp in $gotparents; do
+			if [ "$gp" = "$parent" ]; then
+				is_new=
+				break
+			fi
+		done
+		if [ -n "$is_new" ]; then
+			gotparents="$gotparents $parent"
 			p="$p -p $parent"
 		fi
 	done
 	
-	if [ -n "$identical" -a "$parentmatch" = "$identical" ]; then
+	if [ -n "$identical" -a "$gotparents" = " $identical" ]; then
 		echo $identical
 	else
 		copy_commit $rev $tree "$p" || exit $?

test.sh

@@ -24,8 +24,8 @@ check()
 check_equal()
 {
 	echo
-	echo "check a:" "$1"
-	echo "      b:" "$2"
+	echo "check a:" "{$1}"
+	echo "      b:" "{$2}"
 	if [ "$1" = "$2" ]; then
 		return 0
 	else
@@ -100,17 +100,17 @@ git branch sub2 FETCH_HEAD
 git subtree merge --prefix=subdir FETCH_HEAD
 git branch pre-split
 
-split1=$(git subtree split --annotate='*' \
+spl1=$(git subtree split --annotate='*' \
 		--prefix subdir --onto FETCH_HEAD --rejoin)
-echo "split1={$split1}"
-git branch split1 "$split1"
+echo "spl1={$spl1}"
+git branch spl1 "$spl1"
 
 create subdir/main-sub8
 git commit -m 'main-sub8'
 
 cd ../subproj
-git fetch ../mainline split1
-git branch split1 FETCH_HEAD
+git fetch ../mainline spl1
+git branch spl1 FETCH_HEAD
 git merge FETCH_HEAD
 
 create sub9
@@ -123,14 +123,14 @@ git branch split2 "$split2"
 create subdir/main-sub10
 git commit -m 'main-sub10'
 
-split3=$(git subtree split --annotate='*' --prefix subdir --rejoin)
-git branch split3 "$split3"
+spl3=$(git subtree split --annotate='*' --prefix subdir --rejoin)
+git branch spl3 "$spl3"
 
 cd ../subproj
-git fetch ../mainline split3
-git branch split3 FETCH_HEAD
+git fetch ../mainline spl3
+git branch spl3 FETCH_HEAD
 git merge FETCH_HEAD
-git branch subproj-merge-split3
+git branch subproj-merge-spl3
 
 chkm="main4 main6"
 chkms="main-sub10 main-sub5 main-sub7 main-sub8"
@@ -147,9 +147,9 @@ allchanges=$(git log --name-only --pretty=format:'' | sort | fixnl)
 check_equal "$allchanges" "$chkms $chks"
 
 cd ../mainline
-git fetch ../subproj subproj-merge-split3
-git branch subproj-merge-split3 FETCH_HEAD
-git subtree pull --prefix=subdir ../subproj subproj-merge-split3
+git fetch ../subproj subproj-merge-spl3
+git branch subproj-merge-spl3 FETCH_HEAD
+git subtree pull --prefix=subdir ../subproj subproj-merge-spl3
 
 # make sure exactly the right set of files ends up in the mainline
 mainfiles=$(git ls-files | fixnl)
@@ -162,5 +162,12 @@ check_equal "$mainfiles" "$chkm $chkms_sub $chks_sub"
 allchanges=$(git log --name-only --pretty=format:'' | sort | fixnl)
 check_equal "$allchanges" "$chkm $chkms $chks $chkms_sub"
 
+# make sure the --rejoin commits never make it into subproj
+check_equal "$(git log --pretty=format:'%s' HEAD^2 | grep -i split)" ""
+
+# make sure no 'git subtree' tagged commits make it into subproj. (They're
+# meaningless to subproj since one side of the merge refers to the mainline)
+check_equal "$(git log --pretty=format:'%s%n%b' HEAD^2 | grep 'git-subtree.*:')" ""
+
 echo
 echo 'ok'