rehearse: enable rehearsing jobs using config from roe/release

Rehearsals work over in-repo configuration, but our config can be split
between two repos (openshift/release and r-o-e/release). A job in
openshift/release that uses a config for r-o-e/release will fail to be
rehearsed, because its ci-operator config will not be found. We can
solve this by checking out both repos and unifying them.

While it can be argued we should not have such cross-repo jobs, we will
definitely need to have jobs in r-o-e that use steps from a common
registry, and we'll need to rehearse such jobs when their steps change,
which can be solved with the same mechanism.

ci-operator/jobs/openshift/release/openshift-release-master-presubmits.yaml

@@ -482,6 +482,10 @@ presubmits:
  cluster: api.ci
  context: ci/prow/pj-rehearse
  decorate: true
+ extra_refs:
+ - base_ref: master
+ org: redhat-operator-ecosystem
+ repo: release
  name: pull-ci-openshift-release-master-pj-rehearse
  optional: true
  rerun_command: /test pj-rehearse
@@ -496,7 +500,7 @@ presubmits:
  - --metrics-output=$(ARTIFACTS)/rehearse-metrics.json
  - --rehearsal-limit=45
  command:
- - /bin/pj-rehearse
+ - ./hack/pj-rehearse.sh
  image: pj-rehearse:latest
  imagePullPolicy: Always
  name: ""

hack/pj-rehearse.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# This script runs the pj-rehearse tool after copying the content of the
+# redhat-operator-ecosystem/release repository to the working directory,
+# so that the content of that repository is considered in rehearsal decisions.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+echo "Copying redhat-operator-ecosystem/release content"
+cp -Rn ../../redhat-operator-ecosystem/release/ci-operator/config/* ./ci-operator/config/
+cp -Rn ../../redhat-operator-ecosystem/release/ci-operator/jobs/* ./ci-operator/jobs/
+
+echo "Running pj-rehearse"
+pj-rehearse "$@"