diff --git a/README.md b/README.md
index 46a825b..35e3475 100644
--- a/README.md
+++ b/README.md
@@ -267,6 +267,10 @@ correct key is provided set in `git_crypt_key`.
 
 * `describe_ref_options`: *Optional.* When populating `.git/describe_ref` use this options to call [`git describe`](https://git-scm.com/docs/git-describe). Defaults to `--always --dirty --broken`.
 
+* `all_branches`: *Optional.* If `true` the flag `--single-branch` will be excluded
+  and all branches will be fetched from the repository. If `false` or not specified,
+  only a single branch (either `source.branch` or the default branch) will be fetched.
+
 #### GPG signature verification
 
 If `commit_verification_keys` or `commit_verification_key_ids` is specified in
diff --git a/assets/in b/assets/in
index 96bea2b..6cc01ae 100755
--- a/assets/in
+++ b/assets/in
@@ -43,6 +43,7 @@ submodule_recursive=$(jq -r '(.params.submodule_recursive // true)' <<< "$payloa
 submodule_remote=$(jq -r '(.params.submodule_remote // false)' <<< "$payload")
 commit_verification_key_ids=$(jq -r '(.source.commit_verification_key_ids // [])[]' <<< "$payload")
 commit_verification_keys=$(jq -r '(.source.commit_verification_keys // [])[]' <<< "$payload")
+all_branches=$(jq -r '(.params.all_branches // false)' <<< "$payload")
 tag_filter=$(jq -r '.source.tag_filter // ""' <<< "$payload")
 tag_regex=$(jq -r '.source.tag_regex // ""' <<< "$payload")
 fetch_tags=$(jq -r '.params.fetch_tags' <<< "$payload")
@@ -94,7 +95,12 @@ if [ "$disable_git_lfs" == "true" ]; then
   export GIT_LFS_SKIP_SMUDGE=1
 fi
 
-git clone --single-branch $depthflag $uri $branchflag $destination $tagflag
+singlebranchflag="--single-branch"
+if [ "$all_branches" == "true" ]; then
+  singlebranchflag=""
+fi
+
+git clone $singlebranchflag $depthflag $uri $branchflag $destination $tagflag
 
 cd $destination
 
diff --git a/assets/out b/assets/out
index 54a882a..1ae415f 100755
--- a/assets/out
+++ b/assets/out
@@ -165,10 +165,10 @@ elif [ "$merge" = "true" ]; then
   while true; do
     echo "merging..."
 
-    git reset --hard $commit_to_push
+    git fetch push-target "refs/notes/*:refs/notes/*" $branch
 
-    git fetch push-target "refs/notes/*:refs/notes/*"
-    git pull --no-edit push-target $branch
+    git checkout push-target/$branch
+    git merge $commit_to_push
 
     result="0"
     push_with_result_check result
diff --git a/dockerfiles/ubuntu/Dockerfile b/dockerfiles/ubuntu/Dockerfile
index fee0c82..ff91d26 100644
--- a/dockerfiles/ubuntu/Dockerfile
+++ b/dockerfiles/ubuntu/Dockerfile
@@ -1,4 +1,4 @@
-ARG base_image=ubuntu:bionic
+ARG base_image=ubuntu:jammy
 
 FROM ${base_image} AS resource
 
diff --git a/test/get.sh b/test/get.sh
index dce6bca..15968ee 100755
--- a/test/get.sh
+++ b/test/get.sh
@@ -91,6 +91,19 @@ it_can_get_from_url_at_override_branch() {
   test "$(git -C $dest rev-parse HEAD)" = $ref
 }
 
+it_can_get_from_url_with_all_branches() {
+  local repo=$(init_repo)
+  local ref=$(make_commit $repo)
+  local dest=$TMPDIR/destination
+
+  get_uri_with_all_branches $repo "master" $dest | jq -e "
+    .version == {ref: $(echo $ref | jq -R .)}
+  "
+
+  git -C $dest show-ref --verify refs/remotes/origin/master
+  git -C $dest show-ref --verify refs/remotes/origin/bogus
+}
+
 it_omits_empty_branch_in_metadata() {
   local repo=$(init_repo)
   local ref1=$(make_commit_to_branch $repo branch-a)
@@ -894,6 +907,7 @@ run it_can_get_from_url_at_ref
 run it_can_get_from_url_at_branch
 run it_can_get_from_url_only_single_branch
 run it_can_get_from_url_at_override_branch
+run it_can_get_from_url_with_all_branches
 run it_omits_empty_branch_in_metadata
 run it_returns_branch_in_metadata
 run it_omits_empty_tags_in_metadata
diff --git a/test/helpers.sh b/test/helpers.sh
index 1ecb42c..79b1d19 100644
--- a/test/helpers.sh
+++ b/test/helpers.sh
@@ -726,6 +726,18 @@ get_uri_with_override_branch() {
   }" | ${resource_dir}/in "$4" | tee /dev/stderr
 }
 
+get_uri_with_all_branches() {
+  jq -n "{
+    source: {
+      uri: $(echo $1 | jq -R .),
+      branch: $(echo $2 | jq -R .),
+    },
+    params: {
+      all_branches: \"true\"
+    }
+  }" | ${resource_dir}/in "$3" | tee /dev/stderr
+}
+
 get_uri_with_git_crypt_key() {
   local git_crypt_key_path=$(git_crypt_fixture_key_path)
   local git_crypt_key_base64_encoded=$(cat $git_crypt_key_path | base64)
diff --git a/test/put.sh b/test/put.sh
index 850be6a..970cd9f 100755
--- a/test/put.sh
+++ b/test/put.sh
@@ -268,7 +268,7 @@ it_can_put_to_url_with_merge_commit() {
   local repo2=$src/repo
   git clone $repo1 $repo2
 
-  # make a commit that will require rebasing
+  # make a commit that will require merging
   local baseref=$(make_commit_to_file $repo1 some-other-file)
 
   local ref=$(make_commit $repo2)
@@ -296,6 +296,11 @@ it_can_put_to_url_with_merge_commit() {
   local latest_merge_ref=$(git -C $repo1 log -n 1 --merges --pretty=format:"%H")
 
   test $latest_merge_ref = $merged_ref
+
+  # confirm first parent correctly matches commit prior to merge
+  local first_parent_ref=$(git -C $repo1 log -n 1 HEAD^1 --pretty=format:"%H")
+
+  test $first_parent_ref = $baseref
 }
 
 it_chooses_the_unmerged_commit_ref() {