git --ancestry-path behavior with multiple negations

git_ancestry_path_with_multiple_negations.bash

#!/bin/bash

set -e

mkdir ancestry_path_test
cd ancestry_path_test
git init

git checkout -b root
echo "R1" > root_file
git add root_file
git commit -m "R1"
git tag R1

git checkout -b featureB R1
echo "B1" > featureB_file
git add featureB_file
git commit -m "B1"
git tag B1

git checkout -b featureA R1
echo "A1" > featureA_file
git add featureA_file
git commit -m "A1"
git tag A1

git checkout -b merge_branch
git merge --no-edit B1
git tag M1

git checkout root
echo "R2" >> root_file
git commit -m "R2" root_file
git tag R2

git checkout featureB
git merge --no-edit R2
git tag B2

git checkout featureA
git merge --no-edit R2
git tag A2

git checkout merge_branch
git merge B2 --no-edit
git tag MB2
git merge A2 --no-edit
git tag MA2

git checkout root
echo "R3" >> root_file
git commit -m "R3" root_file
git tag R3

git checkout featureB
git merge --no-edit R3
git tag B3

git checkout featureA
git merge --no-edit R3
git tag A3

git checkout merge_branch
git merge B3 --no-edit
git tag MB3
git merge A3 --no-edit
git tag MA3

gitk --all &

echo "--ancestry-path ^R2 merge_branch"
git rev-list --ancestry-path ^R2 merge_branch | xargs -i git tag --points-at '{}'
gitk --ancestry-path ^R2 merge_branch &

echo "--ancestry-path ^R2 ^featureB merge_branch"
git rev-list --ancestry-path ^R2 ^featureB merge_branch | xargs -i git tag --points-at '{}'
gitk --ancestry-path ^R2 ^featureB merge_branch &