Add the ability to set refs_prefix for the push

Normal branches all exist in refs/heads but some git workflows require
pushing to a different type of reference.

For example Gerrit Reviews are created/updated by pushing to a 'magic'
ref at `refs/for/<branch>`

Signed-off-by: Jamie Pate <jpate@fortinet.com>

README.md

@@ -330,6 +330,8 @@ pushed regardless of the upstream state.
   even if the `branch` differs from the `branch` specified in the source.
   To avoid this, you should use two resources of read-only and write-only.
 
+* `refs_prefix`: *Optional.* Allows pushing to refs other than heads. Defaults to `refs/heads`.
+
 ## Development
 
 ### Prerequisites

assets/out

@@ -39,6 +39,8 @@ only_tag=$(jq -r '.params.only_tag // false' <<< "$payload")
 annotation_file=$(jq -r '.params.annotate // ""' <<< "$payload")
 notes_file=$(jq -r '.params.notes // ""' <<< "$payload")
 override_branch=$(jq -r '.params.branch // ""' <<< "$payload")
+# useful for pushing to special ref types like refs/for in gerrit.
+refs_prefix=$(jq -r '.params.refs_prefix // "refs/heads"' <<< "$payload")
 
 configure_git_global "${git_config_payload}"
 
@@ -103,7 +105,7 @@ tag() {
 }
 
 push_src_and_tags() {
-  git push --tags push-target HEAD:refs/heads/$branch $forceflag
+  git push --tags push-target HEAD:$refs_prefix/$branch $forceflag
 }
 
 push_tags() {

test/helpers.sh

@@ -1238,3 +1238,16 @@ put_uri_with_config() {
     }
   }" | ${resource_dir}/out "$2" | tee /dev/stderr
 }
+
+put_uri_with_refs_prefix() {
+  jq -n "{
+    source: {
+      uri: $(echo $1 | jq -R .),
+      branch: \"master\"
+    },
+    params: {
+      repository: $(echo $3 | jq -R .),
+      refs_prefix: $(echo $4 | jq -R .),
+    }
+  }" | ${resource_dir}/out "$2" | tee /dev/stderr
+}

test/put.sh

@@ -585,6 +585,29 @@ it_will_fail_put_with_conflicting_tag_and_not_force_push() {
   test "$(git -C $repo1 rev-parse some-only-tag)" = $expected_ref
 }
 
+it_can_put_with_refs_prefix() {
+  local repo1=$(init_repo)
+
+  local src=$(mktemp -d $TMPDIR/put-src.XXXXXX)
+  local repo2=$src/repo
+  git clone $repo1 $repo2
+
+  local ref=$(make_commit $repo2)
+
+  # cannot push to repo while it's checked out to a branch
+  git -C $repo1 checkout refs/heads/master
+  set -x
+  put_uri_with_refs_prefix $repo1 $src repo refs/for | jq -e "
+    .version == {ref: $(echo $ref | jq -R .)}
+  "
+
+  # switch back to master
+  git -C $repo1 checkout refs/for/master
+
+  test -e $repo1/some-file
+  test "$(git -C $repo1 rev-parse HEAD)" = $ref
+}
+
 run it_can_put_to_url
 run it_can_put_to_url_with_branch
 run it_returns_branch_in_metadata
@@ -605,3 +628,4 @@ run it_will_fail_put_if_conflicts_and_not_force_push
 run it_can_put_and_force_the_push
 run it_can_put_to_url_with_only_tag_and_force_the_push
 run it_will_fail_put_with_conflicting_tag_and_not_force_push
+run it_can_put_with_refs_prefix