Fix release pipeline to handle #1122

Since #1122, we do not treat outputs that were inputs as well in any
special way, meaning that the output folder will be empty unless we
copy the input to the output.

Fix the release pipeline to handle that.

Fixes: #1325

tekton/publish.yaml

@@ -87,13 +87,21 @@ spec:
 
       cat /workspace/go/src/github.com/tektoncd/pipeline/.ko.yaml
 
+  - name: link-input-bucket-to-output
+    image: busybox
+    command: ["cp"]
+    args:
+    - -r
+    - "/workspace/bucket"
+    - "/workspace/output/"
+
   - name: ensure-release-dirs-exist
     image: busybox
     command: ["mkdir"]
     args:
     - "-p"
-    - "/workspace/bucket/latest/"
-    - "/workspace/bucket/previous/"
+    - "/workspace/output/bucket/latest/"
+    - "/workspace/output/bucket/previous/"
 
   - name: run-ko
     # TODO(#639) we should be able to use the image built by an upstream Task here instead of hardcoding
@@ -123,14 +131,14 @@ spec:
       cd /workspace/go/src/github.com/tektoncd/pipeline
 
       # Publish images and create release.yaml
-      ko resolve --preserve-import-paths -f /workspace/go/src/github.com/tektoncd/pipeline/config/ > /workspace/bucket/latest/release.yaml
+      ko resolve --preserve-import-paths -f /workspace/go/src/github.com/tektoncd/pipeline/config/ > /workspace/output/bucket/latest/release.yaml
     volumeMounts:
       - name: gcp-secret
         mountPath: /secret
 
   - name: copy-to-tagged-bucket
     image: busybox
-    workingDir: "/workspace/bucket"
+    workingDir: "/workspace/output/bucket"
     command:
     - /bin/sh
     args:
@@ -139,8 +147,8 @@ spec:
       set -e
       set -x
 
-      mkdir -p /workspace/bucket/previous/$(inputs.params.versionTag)/
-      cp /workspace/bucket/latest/release.yaml /workspace/bucket/previous/$(inputs.params.versionTag)/release.yaml
+      mkdir -p /workspace/output/bucket/previous/$(inputs.params.versionTag)/
+      cp /workspace/output/bucket/latest/release.yaml /workspace/output/bucket/previous/$(inputs.params.versionTag)/release.yaml
 
   - name: tag-images
     image: google/cloud-sdk
@@ -168,7 +176,7 @@ spec:
         ${inputs.params.imageRegistry}/${inputs.params.pathToProject}/${outputs.resources.builtGcsFetcherImage.url}
       )
       # Parse the built images from the release.yaml generated by ko
-      BUILT_IMAGES=( $(/workspace/go/src/github.com/tektoncd/pipeline/tekton/koparse/koparse.py --path /workspace/bucket/latest/release.yaml --base ${inputs.params.imageRegistry}/${inputs.params.pathToProject} --images ${IMAGES[@]}) )
+      BUILT_IMAGES=( $(/workspace/go/src/github.com/tektoncd/pipeline/tekton/koparse/koparse.py --path /workspace/output/bucket/latest/release.yaml --base ${inputs.params.imageRegistry}/${inputs.params.pathToProject} --images ${IMAGES[@]}) )
 
       # Auth with account credentials
       gcloud auth activate-service-account --key-file=/secret/release.json